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diff --git a/.gitattributes b/.gitattributes new file mode 100644 index 0000000..6833f05 --- /dev/null +++ b/.gitattributes @@ -0,0 +1,3 @@ +* text=auto +*.txt text +*.md text diff --git a/29241-8.txt b/29241-8.txt new file mode 100644 index 0000000..9539673 --- /dev/null +++ b/29241-8.txt @@ -0,0 +1,4627 @@ +The Project Gutenberg EBook of Little Masterpieces of Science:, by Various + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Little Masterpieces of Science: + Invention and Discovery + +Author: Various + +Editor: George Iles + +Release Date: June 25, 2009 [EBook #29241] + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK LITTLE MASTERPIECES OF SCIENCE: *** + + + + +Produced by Sigal Alon, Marcia Brooks, Fox in the Stars +and the Online Distributed Proofreading Team at +http://www.pgdp.net + + + + + + + + + +LITTLE MASTERPIECES OF SCIENCE + +[Illustration: George Stephenson.] + + + + +Little Masterpieces +of Science + +Edited by George Iles + + + + +INVENTION AND DISCOVERY + + +_By_ + + +Benjamin Franklin Alexander Graham Bell +Michael Faraday Count Rumford +Joseph Henry George Stephenson + + +[Illustration] + + +NEW YORK + +DOUBLEDAY, PAGE & COMPANY + +1902 + + +Copyright, 1902, by Doubleday, Page & Co. + +Copyright, 1877, by George B. Prescott + +Copyright, 1896, by S. S. McClure Co. + +Copyright, 1900, by Doubleday, McClure & Co. + + + + +PREFACE + + +To a good many of us the inventor is the true hero for he multiplies the +working value of life. He performs an old task with new economy, as when +he devises a mowing-machine to oust the scythe; or he creates a service +wholly new, as when he bids a landscape depict itself on a photographic +plate. He, and his twin brother, the discoverer, have eyes to read a +lesson that Nature has held for ages under the undiscerning gaze of +other men. Where an ordinary observer sees, or thinks he sees, +diversity, a Franklin detects identity, as in the famous experiment here +recounted which proves lightning to be one and the same with a charge of +the Leyden jar. Of a later day than Franklin, advantaged therefor by new +knowledge and better opportunities for experiment, stood Faraday, the +founder of modern electric art. His work gave the world the dynamo and +motor, the transmission of giant powers, almost without toll, for two +hundred miles at a bound. It is, however, in the carriage of but +trifling quantities of motion, just enough for signals, that electricity +thus far has done its most telling work. Among the men who have created +the electric telegraph Joseph Henry has a commanding place. A short +account of what he did, told in his own words, is here presented. Then +follows a narrative of the difficult task of laying the first Atlantic +cables, a task long scouted as impossible: it is a story which proves +how much science may be indebted to unfaltering courage, to faith in +ultimate triumph. + +To give speech the wings of electricity, to enable friends in Denver and +New York to converse with one another, is a marvel which only +familiarity places beyond the pale of miracle. Shortly after he +perfected the telephone Professor Bell described the steps which led to +its construction. That recital is here reprinted. + +A recent wonder of electric art is its penetration by a photographic ray +of substances until now called opaque. Professor Röntgen's account of +how he wrought this feat forms one of the most stirring chapters in the +history of science. Next follows an account of the telegraph as it +dispenses with metallic conductors altogether, and trusts itself to that +weightless ether which brings to the eye the luminous wave. To this +succeeds a chapter which considers what electricity stands for as one of +the supreme resources of human wit, a resource transcending even flame +itself, bringing articulate speech and writing to new planes of facility +and usefulness. It is shown that the rapidity with which during a single +century electricity has been subdued for human service, illustrates that +progress has leaps as well as deliberate steps, so that at last a gulf, +all but infinite, divides man from his next of kin. + +At this point we pause to recall our debt to the physical philosophy +which underlies the calculations of the modern engineer. In such an +experiment as that of Count Rumford we observe how the corner-stone was +laid of the knowledge that heat is motion, and that motion under +whatever guise, as light, electricity, or what not, is equally beyond +creation or annihilation, however elusively it may glide from phase to +phase and vanish from view. In the mastery of Flame for the superseding +of muscle, of breeze and waterfall, the chief credit rests with James +Watt, the inventor of the steam engine. Beside him stands George +Stephenson, who devised the locomotive which by abridging space has +lengthened life and added to its highest pleasures. Our volume closes by +narrating the competition which decided that Stephenson's "Rocket" was +much superior to its rivals, and thus opened a new chapter in the +history of mankind. + +GEORGE ILES. + + + + +CONTENTS + + + FRANKLIN, BENJAMIN + + LIGHTNING IDENTIFIED WITH ELECTRICITY + + Franklin explains the action of the Leyden phial or jar. + Suggests lightning-rods. Sends a kite into the clouds during + a thunderstorm; through the kite-string obtains a spark + of lightning which throws into divergence the loose fibres + of the string, just as an ordinary electrical discharge + would do. 3 + + + FARADAY, MICHAEL + + PREPARING THE WAY FOR THE ELECTRIC DYNAMO AND MOTOR + + Notices the inductive effect in one coil when the circuit in + a concentric coil is completed or broken. Notices similar + effects when a wire bearing a current approaches another + wire or recedes from it. Rotates a galvanometer needle by + an electric pulse. Induces currents in coils when the magnetism + is varied in their iron or steel cores. Observes the lines + of magnetic force as iron filings are magnetized. A magnetic + bar moved in and out of a coil of wire excites electricity + therein,--mechanical motion is converted into electricity. + Generates a current by spinning a copper plate in a horizontal + plane. 7 + + + HENRY, JOSEPH + + INVENTION OF THE ELECTRIC TELEGRAPH + + Improves the electro-magnet of Sturgeon by insulating its + wire with silk thread, and by disposing the wire in several + coils instead of one. Experiments with a large electro-magnet + excited by nine distinct coils. Uses a battery so powerful + that electro-magnets are produced one hundred times more + energetic than those of Sturgeon. Arranges a telegraphic + circuit more than a mile long and at that distance sounds + a bell by means of an electro-magnet. 23 + + + ILES, GEORGE + + THE FIRST ATLANTIC CABLES + + Forerunners at New York and Dover. Gutta-percha the indispensable + insulator. Wire is used to sheathe the cables. Cyrus W. + Field's project for an Atlantic cable. The first cable fails. + 1858 so does the second cable 1865. A triumph of courage, + 1866. The highway smoothed for successors. Lessons of the + cable. 37 + + + BELL, ALEXANDER GRAHAM + + THE INVENTION OF THE TELEPHONE + + Indebted to his father's study of the vocal organs as they + form sounds. Examines the Helmholtz method for the analysis + and synthesis of vocal sounds. Suggests the electrical actuation + of tuning-forks and the electrical transmission of their + tones. Distinguishes intermittent, pulsatory and undulatory + currents. Devises as his first articulating telephone a harp + of steel rods thrown into vibration by electro-magnetism. + Exhibits optically the vibrations of sound, using a preparation + of a human ear: is struck by the efficiency of a slight + aural membrane. Attaches a bit of clock spring to a piece + of goldbeater's skin, speaks to it, an audible message is + received at a distant and similar device. This contrivance + improved is shown at the Centennial Exhibition, Philadelphia, + 1876. At first the same kind of instrument transmitted and + delivered, a message; soon two distinct instruments were + invented for transmitting and for receiving. Extremely small + magnets suffice. A single blade of grass forms a telephonic + circuit. 57 + + + DAM, H. J. W. + + PHOTOGRAPHING THE UNSEEN + + Röntgen indebted to the researches of Faraday, Clerk-Maxwell, + Hertz, Lodge and Lenard. The human optic nerve is affected + by a very small range in the waves that exist in the ether. + Beyond the visible spectrum of common light are vibrations + which have long been known as heat or as photographically + active. Crookes in a vacuous bulb produced soft light from + high tension electricity. Lenard found that rays from a + Crookes' tube passed through substances opaque to common + light. Röntgen extended these experiments and used the rays + photographically, taking pictures of the bones of the hand + through living flesh, and so on. 87 + + + ILES, GEORGE + + THE WIRELESS TELEGRAPH + + What may follow upon electric induction. Telegraphy to a + moving train. The Preece induction method; its limits. + Marconi's system. His precursors, Hertz, Onesti, Branly + and Lodge. The coherer and the vertical wire form the essence + of the apparatus. Wireless telegraphy at sea. 109 + + + ILES, GEORGE + + ELECTRICITY, WHAT ITS MASTERY MEANS: WITH A REVIEW AND A PROSPECT + + Electricity does all that fire ever did, does it better, + and performs uncounted services impossible to flame. Its + mastery means as great a forward stride as the subjugation + of fire. A minor invention or discovery simply adds to human + resources: a supreme conquest as of flame or electricity, + is a multiplier and lifts art and science to a new plane. + Growth is slow, flowering is rapid: progress at times is + so quick of pace as virtually to become a leap. The mastery + of electricity based on that of fire. Electricity vastly + wider of range than heat: it is energy in its most available + and desirable phase. The telegraph and the telephone contrasted + with the signal fire. Electricity as the servant of mechanic + and engineer. Household uses of the current. Electricity + as an agent of research now examines Nature in fresh aspects. + The investigator and the commercial exploiter render aid to + one another. Social benefits of electricity, in telegraphy, in + quick travel. The current should serve every city house. 125 + + + RUMFORD, COUNT (BENJAMIN THOMPSON) + + HEAT AND MOTION IDENTIFIED + + Observes that in boring a cannon much heat is generated: + the longer the boring lasts, the more heat is produced. He + argues that since heat without limit may be thus produced + by motion, heat must be motion. 155 + + + STEPHENSON, GEORGE + + THE "ROCKET" LOCOMOTIVE AND ITS VICTORY + + Shall it be a system of stationary engines or locomotives? + The two best practical engineers of the day are in favour + of stationary engines. A test of locomotives is, however, + proffered, and George Stephenson and his son, Robert, discuss + how they may best build an engine to win the first prize. + They adopt a steam blast to stimulate the draft of the furnace, + and raise steam quickly in a boiler having twenty-five small + fire-tubes of copper. The "Rocket" with a maximum speed of + twenty-nine miles an hour distances its rivals. With its + load of water its weight was but four and a quarter tons. 163 + + + + +INVENTION AND DISCOVERY + + + + +FRANKLIN IDENTIFIES LIGHTNING WITH ELECTRICITY + + [From Franklin's Works, edited in ten volumes by John Bigelow, Vol. + I, pages 276-281, copyright by G. P. Putnam's Sons, New York.] + + +Dr. Stuber, the author of the first continuation of Franklin's life, +gives this account of the electrical experiments of Franklin:-- + +"His observations he communicated, in a series of letters, to his friend +Collinson, the first of which is dated March 28, 1747. In these he shows +the power of points in drawing and throwing off the electrical matter, +which had hitherto escaped the notice of electricians. He also made the +grand discovery of a _plus_ and _minus_, or of a _positive_ and +_negative_ state of electricity. We give him the honour of this without +hesitation; although the English have claimed it for their countryman, +Dr. Watson. Watson's paper is dated January 21, 1748; Franklin's July +11, 1747, several months prior. Shortly after Franklin, from his +principles of the _plus_ and _minus_ state, explained in a satisfactory +manner the phenomena of the Leyden phial, first observed by Mr. Cuneus, +or by Professor Muschenbroeck, of Leyden, which had much perplexed +philosophers. He showed clearly that when charged the bottle contained +no more electricity than before, but that as much was taken from one +side as thrown on the other; and that to discharge it nothing was +necessary but to produce a communication between the two sides by which +the equilibrium might be restored, and that then no signs of electricity +would remain. He afterwards demonstrated by experiments that the +electricity did not reside in the coating as had been supposed, but in +the pores of the glass itself. After the phial was charged he removed +the coating, and found that upon applying a new coating the shock might +still be received. In the year 1749, he first suggested his idea of +explaining the phenomena of thunder gusts and of _aurora borealis_ upon +electric principles. He points out many particulars in which lightning +and electricity agree; and he adduces many facts, and reasonings from +facts, in support of his positions. + +"In the same year he conceived the astonishingly bold and grand idea of +ascertaining the truth of his doctrine by actually drawing down the +lightning, by means of sharp pointed iron rods raised into the regions +of the clouds. Even in this uncertain state his passion to be useful to +mankind displayed itself in a powerful manner. Admitting the identity of +electricity and lightning, and knowing the power of points in repelling +bodies charged with electricity, and in conducting fires silently and +imperceptibly, he suggested the idea of securing houses, ships and the +like from being damaged by lightning, by erecting pointed rods that +should rise some feet above the most elevated part, and descend some +feet into the ground or water. The effect of these he concluded would be +either to prevent a stroke by repelling the cloud beyond the striking +distance or by drawing off the electrical fire which it contained; or, +if they could not effect this they would at least conduct the electrical +matter to the earth without any injury to the building. + +"It was not until the summer of 1752 that he was enabled to complete his +grand and unparalleled discovery by experiment. The plan which he had +originally proposed was, to erect, on some high tower or elevated place, +a sentry-box from which should rise a pointed iron rod, insulated by +being fixed in a cake of resin. Electrified clouds passing over this +would, he conceived, impart to it a portion of their electricity which +would be rendered evident to the senses by sparks being emitted when a +key, the knuckle, or other conductor, was presented to it. Philadelphia +at this time afforded no opportunity of trying an experiment of this +kind. While Franklin was waiting for the erection of a spire, it +occurred to him that he might have more ready access to the region of +clouds by means of a common kite. He prepared one by fastening two cross +sticks to a silk handkerchief, which would not suffer so much from the +rain as paper. To the upright stick was affixed an iron point. The +string was, as usual, of hemp, except the lower end, which was silk. +Where the hempen string terminated, a key was fastened. With this +apparatus, on the appearance of a thundergust approaching, he went out +into the commons, accompanied by his son, to whom alone he communicated +his intentions, well knowing the ridicule which, too generally for the +interest of science, awaits unsuccessful experiments in philosophy. He +placed himself under a shed, to avoid the rain; his kite was raised, a +thunder-cloud passed over it, no sign of electricity appeared. He almost +despaired of success, when suddenly he observed the loose fibres of his +string to move towards an erect position. He now presented his knuckle +to the key and received a strong spark. How exquisite must his +sensations have been at this moment! On his experiment depended the fate +of his theory. If he succeeded, his name would rank high among those who +had improved science; if he failed, he must inevitably be subjected to +the derision of mankind, or, what is worse, their pity, as a +well-meaning man, but a weak, silly projector. The anxiety with which he +looked for the result of his experiment may easily be conceived. Doubts +and despair had begun to prevail, when the fact was ascertained, in so +clear a manner, that even the most incredulous could no longer withhold +their assent. Repeated sparks were drawn from the key, a phial was +charged, a shock given, and all the experiments made which are usually +performed with electricity." + + + + +FARADAY'S DISCOVERIES LEADING UP TO THE ELECTRIC DYNAMO AND MOTOR + + [Michael Faraday was for many years Professor of Natural Philosophy + at the Royal Institution, London, where his researches did more to + subdue electricity to the service of man than those of any other + physicist who ever lived. "Faraday as a Discoverer," by Professor + John Tyndall (his successor) depicts a mind of the rarest ability + and a character of the utmost charm. This biography is published by + D. Appleton & Co., New York: the extracts which follow are from the + third chapter.] + + +In 1831 we have Faraday at the climax of his intellectual strength, +forty years of age, stored with knowledge and full of original power. +Through reading, lecturing, and experimenting, he had become thoroughly +familiar with electrical science: he saw where light was needed and +expansion possible. The phenomena of ordinary electric induction +belonged, as it were, to the alphabet of his knowledge: he knew that +under ordinary circumstances the presence of an electrified body was +sufficient to excite, by induction, an unelectrified body. He knew that +the wire which carried an electric current was an electrified body, and +still that all attempts had failed to make it excite in other wires a +state similar to its own. + +What was the reason of this failure? Faraday never could work from the +experiments of others, however clearly described. He knew well that from +every experiment issues a kind of radiation, luminous, in different +degrees to different minds, and he hardly trusted himself to reason upon +an experiment that he had not seen. In the autumn of 1831 he began to +repeat the experiments with electric currents, which, up to that time, +had produced no positive result. And here, for the sake of younger +inquirers, if not for the sake of us all, it is worth while to dwell for +a moment on a power which Faraday possessed in an extraordinary degree. +He united vast strength with perfect flexibility. His momentum was that +of a river, which combines weight and directness with the ability to +yield to the flexures of its bed. The intentness of his vision in any +direction did not apparently diminish his power of perception in other +directions; and when he attacked a subject, expecting results, he had +the faculty of keeping his mind alert, so that results different from +those which he expected should not escape him through pre-occupation. + +He began his experiments "on the induction of electric currents" by +composing a helix of two insulated wires, which were wound side by side +round the same wooden cylinder. One of these wires he connected with a +voltaic battery of ten cells, and the other with a sensitive +galvanometer. When connection with the battery was made, and while the +current flowed, no effect whatever was observed at the galvanometer. +But he never accepted an experimental result, until he had applied to +it the utmost power at his command. He raised his battery from ten cells +to one hundred and twenty cells, but without avail. The current flowed +calmly through the battery wire without producing, during its flow, any +sensible result upon the galvanometer. + +"During its flow," and this was the time when an effect was +expected--but here Faraday's power of lateral vision, separating, as it +were from the line of expectation, came into play--he noticed that a +feeble movement of the needle always occurred at the moment when he made +contact with the battery; that the needle would afterwards return to its +former position and remain quietly there unaffected by the _flowing_ +current. At the moment, however, when the circuit was interrupted the +needle again moved, and in a direction opposed to that observed on the +completion of the circuit. + +This result, and others of a similar kind, led him to the conclusion +"that the battery current through the one wire did in reality induce a +similar current through the other; but that it continued for an instant +only, and partook more of the nature of the electric wave from a common +Leyden jar than of the current from a voltaic battery." The momentary +currents thus generated were called _induced currents_, while the +current which generated them was called the _inducing_ current. It was +immediately proved that the current generated at making the circuit was +always opposed in direction to its generator, while that developed on +the rupture of the circuit coincided in direction with the inducing +current. It appeared as if the current on its first rush through the +primary wire sought a purchase in the secondary one, and, by a kind of +kick, impelled backward through the latter an electric wave, which +subsided as soon as the primary current was fully established. + +Faraday, for a time, believed that the secondary wire, though quiescent +when the primary current had been once established, was not in its +natural condition, its return to that condition being declared by the +current observed at breaking the circuit. He called this hypothetical +state of the wire the _electro-tonic state_: he afterwards abandoned +this hypothesis, but seemed to return to it in after life. The term +electro-tonic is also preserved by Professor Du Bois Reymond to express +a certain electric condition of the nerves, and Professor Clerk Maxwell +has ably defined and illustrated the hypothesis in the Tenth Volume of +the "Transactions of the Cambridge Philosophical Society." + +The mere approach of a wire forming a closed curve to a second wire +through which a voltaic current flowed was then shown by Faraday to be +sufficient to arouse in the neutral wire an induced current, opposed in +direction to the inducing current; the withdrawal of the wire also +generated a current having the same direction as the inducing current; +those currents existed only during the time of approach or withdrawal, +and when neither the primary nor the secondary wire was in motion, no +matter how close their proximity might be, no induced current was +generated. + +Faraday has been called a purely inductive philosopher. A great deal of +nonsense is, I fear, uttered in this land of England about induction and +deduction. Some profess to befriend the one, some the other, while the +real vocation of an investigator, like Faraday, consists in the +incessant marriage of both. He was at this time full of the theory of +Ampère, and it cannot be doubted that numbers of his experiments were +executed merely to test his deductions from that theory. Starting from +the discovery of Oersted, the celebrated French philosopher had shown +that all the phenomena of magnetism then known might be reduced to the +mutual attractions and repulsions of electric currents. Magnetism had +been produced from electricity, and Faraday, who all his life long +entertained a strong belief in such reciprocal actions, now attempted to +effect the evolution of electricity from magnetism. Round a welded iron +ring he placed two distinct coils of covered wire, causing the coils to +occupy opposite halves of the ring. Connecting the ends of one of the +coils with a galvanometer, he found that the moment the ring was +magnetized, by sending a current through _the other coil_, the +galvanometer needle whirled round four or five times in succession. The +action, as before, was that of a pulse, which vanished immediately. On +interrupting the current, a whirl of the needle in the opposite +direction occurred. It was only during the time of magnetization or +demagnetization that these effects were produced. The induced currents +declared a _change_ of condition only, and they vanished the moment the +act of magnetization or demagnetization was complete. + +The effects obtained with the welded ring were also obtained with +straight bars of iron. Whether the bars were magnetized by the electric +current, or were excited by the contact of permanent steel magnets, +induced currents were always generated during the rise, and during the +subsidence of the magnetism. The use of iron was then abandoned, and the +same effects were obtained by merely thrusting a permanent steel magnet +into a coil of wire. A rush of electricity through the coil accompanied +the insertion of the magnet; an equal rush in the opposite direction +accompanied its withdrawal. The precision with which Faraday describes +these results, and the completeness with which he defined the boundaries +of his facts, are wonderful. The magnet, for example, must not be passed +quite through the coil, but only half through, for if passed wholly +through, the needle is stopped as by a blow, and then he shows how this +blow results from a reversal of the electric wave in the helix. He next +operated with the powerful permanent magnet of the Royal Society, and +obtained with it, in an exalted degree, all the foregoing phenomena. + +And now he turned the light of these discoveries upon the darkest +physical phenomenon of that day. Arago had discovered in 1824, that a +disk of non-magnetic metal had the power of bringing a vibrating +magnetic needle suspended over it rapidly to rest; and that on causing +the disk to rotate the magnetic needle rotated along with it. When both +were quiescent, there was not the slightest measurable attraction or +repulsion exerted between the needle and the disk; still when in motion +the disk was competent to drag after it, not only a light needle, but a +heavy magnet. The question had been probed and investigated with +admirable skill by both Arago and Ampère, and Poisson had published a +theoretic memoir on the subject; but no cause could be assigned for so +extraordinary an action. It had also been examined in this country by +two celebrated men, Mr. Babbage and Sir John Herschel; but it still +remained a mystery. Faraday always recommended the suspension of +judgment in cases of doubt. "I have always admired," he says, "the +prudence and philosophical reserve shown by M. Arago in resisting the +temptations to give a theory of the effect he had discovered, so long as +he could not devise one which was perfect in its application, and in +refusing to assent to the imperfect theories of others." Now, however, +the time for theory had come. Faraday saw mentally the rotating disk, +under the operation of the magnet, flooded with his induced currents, +and from the known laws of interaction between currents and magnets he +hoped to deduce the motion observed by Arago. That hope he realized, +showing by actual experiment that when his disk rotated currents passed +through it, their position and direction being such as must, in +accordance with the established laws of electro-magnetic action, produce +the observed rotation. + +Introducing the edge of his disk between the poles of the large +horseshoe magnet of the Royal Society, and connecting the axis and the +edge of the disk, each by a wire with a galvanometer, he obtained, when +the disk was turned round, a constant flow of electricity. The direction +of the current was determined by the direction of the motion, the +current being reversed when the rotation was reversed. He now states the +law which rules the production of currents in both disks and wires, and +in so doing uses, for the first time, a phrase which has since become +famous. When iron filings are scattered over a magnet, the particles of +iron arrange themselves in certain determined lines called magnetic +curves. In 1831, Faraday for the first time called these curves "lines +of magnetic force;" and he showed that to produce induced currents +neither approach to nor withdrawal from a magnetic source, or centre, or +pole, was essential, but that it was only necessary to cut appropriately +the lines of magnetic force. Faraday's first paper on Magneto-electric +Induction, which I have here endeavoured to condense, was read before +the Royal Society on the 24th of November, 1831. + +On January 12, 1832, he communicated to the Royal Society a second paper +on "Terrestrial Magneto-electric Induction," which was chosen as the +Bakerian Lecture for the year. He placed a bar of iron in a coil of +wire, and lifting the bar into the direction of the dipping needle, he +excited by this action a current in the coil. On reversing the bar, a +current in the opposite direction rushed through the wire. The same +effect was produced, when, on holding the helix in the line of dip, a +bar of iron was thrust into it. Here, however, the earth acted on the +coil through the intermediation of the bar of iron. He abandoned the bar +and simply set a copper-plate spinning in a horizontal plane; he knew +that the earth's lines of magnetic force then crossed the plate at an +angle of about 70°. When the plate spun round, the lines of force were +intersected and induced currents generated, which produced their proper +effect when carried from the plate to the galvanometer. "When the plate +was in the magnetic meridian, or in any other plane coinciding with the +magnetic dip, then its rotation produced no effect upon the +galvanometer." + +At the suggestion of a mind fruitful in suggestions of a profound and +philosophic character--I mean that of Sir John Herschel--Mr. Barlow, of +Woolwich, had experimented with a rotating iron shell. Mr. Christie had +also performed an elaborate series of experiments on a rotating iron +disk. Both of them had found that when in rotation the body exercised a +peculiar action upon the magnetic needle, deflecting it in a manner +which was not observed during quiescence; but neither of them was aware +at the time of the agent which produced this extraordinary deflection. +They ascribed it to some change in the magnetism of the iron shell and +disk. + +But Faraday at once saw that his induced currents must come into play +here, and he immediately obtained them from an iron disk. With a hollow +brass ball, moreover, he produced the effects obtained by Mr. Barlow. +Iron was in no way necessary: the only condition of success was that the +rotating body should be of a character to admit of the formation of +currents in its substance: it must, in other words, be a conductor of +electricity. The higher the conducting power the more copious were the +currents. He now passes from his little brass globe to the globe of the +earth. He plays like a magician with the earth's magnetism. He sees the +invisible lines along which its magnetic action is exerted and sweeping +his wand across these lines evokes this new power. Placing a simple loop +of wire round a magnetic needle he bends its upper portion to the west: +the north pole of the needle immediately swerves to the east: he bends +his loop to the east, and the north poles moves to the west. Suspending +a common bar magnet in a vertical position, he causes it to spin round +its own axis. Its pole being connected with one end of a galvanometer +wire, and its equator with the other end, electricity rushes round the +galvanometer from the rotating magnet. He remarks upon the "_singular +independence_" of the magnetism and the body of the magnet which carries +it. The steel behaves as if it were isolated from its own magnetism. + +And then his thoughts suddenly widen, and he asks himself whether the +rotating earth does not generate induced currents as it turns round its +axis from west to east. In his experiment with the twirling magnet the +galvanometer wire remained at rest; one portion of the circuit was in +motion _relatively_ to _another portion_. But in the case of the +twirling planet the galvanometer wire would necessarily be carried along +with the earth; there would be no relative motion. What must be the +consequence? Take the case of a telegraph wire with its two terminal +plates dipped into the earth, and suppose the wire to lie in the +magnetic meridian. The ground underneath the wire is influenced like the +wire itself by the earth's rotation; if a current from south to north be +generated in the wire, a similar current from south to north would be +generated in the earth under the wire; these currents would run against +the same terminal plates, and thus neutralize each other. + +This inference appears inevitable, but his profound vision perceived its +possible invalidity. He saw that it was at least possible that the +difference of conducting power between the earth and the wire might +give one an advantage over the other, and that thus a residual or +differential current might be obtained. He combined wires of different +materials, and caused them to act in opposition to each other, but found +the combination ineffectual. The more copious flow in the better +conductor was exactly counterbalanced by the resistance of the worst. +Still, though experiment was thus emphatic, he would clear his mind of +all discomfort by operating on the earth itself. He went to the round +lake near Kensington Palace, and stretched four hundred and eighty feet +of copper wire, north and south, over the lake, causing plates soldered +to the wire at its ends to dip into the water. The copper wire was +severed at the middle, and the severed ends connected with a +galvanometer. No effect whatever was observed. But though quiescent +water gave no effect, moving water might. He therefore worked at London +Bridge for three days during the ebb and flow of the tide, but without +any satisfactory result. Still he urges, "Theoretically it seems a +necessary consequence, that where water is flowing there electric +currents should be formed. If a line be imagined passing from Dover to +Calais through the sea, and returning through the land, beneath the +water, to Dover, it traces out a circuit of conducting matter one part +of which, when the water moves up or down the channel, is cutting the +magnetic curves of the earth, while the other is relatively at rest.... +There is every reason to believe that currents do run in the general +direction of the circuit described, either one way or the other, +according as the passage of the waters is up or down the channel." This +was written before the submarine cable was thought of, and he once +informed me that actual observation upon that cable had been found to be +in accordance with his theoretic deduction. + +Three years subsequent to the publication of these researches, that is +to say on January 29, 1835, Faraday read before the Royal Society a +paper "On the influence by induction of an electric current upon +itself." A shock and spark of a peculiar character had been observed by +a young man named William Jenkin, who must have been a youth of some +scientific promise, but who, as Faraday once informed me, was dissuaded +by his own father from having anything to do with science. The +investigation of the fact noticed by Mr. Jenkin led Faraday to the +discovery of the _extra current_, or the current _induced in the primary +wire itself_ at the moments of making and breaking contact, the +phenomena of which he described and illustrated in the beautiful and +exhaustive paper referred to. + +Seven and thirty years have passed since the discovery of +magneto-electricity; but, if we except the _extra current_, until quite +recently nothing of moment was added to the subject. Faraday entertained +the opinion that the discoverer of a great law or principle had a right +to the "spoils"--this was his term--arising from its illustration; and +guided by the principle he had discovered, his wonderful mind, aided by +his wonderful ten fingers, overran in a single autumn this vast domain, +and hardly left behind him the shred of a fact to be gathered by his +successors. + +And here the question may arise in some minds, What is the use of it +all? The answer is, that if man's intellectual nature thirsts for +knowledge then knowledge is useful because it satisfies this thirst. If +you demand practical ends, you must, I think, expand your definition of +the term practical, and make it include all that elevates and enlightens +the intellect, as well as all that ministers to the bodily health and +comfort of men. Still, if needed, an answer of another kind might be +given to the question "what is its use?" As far as electricity has been +applied for medical purposes, it has been almost exclusively Faraday's +electricity. You have noticed those lines of wire which cross the +streets of London. It is Faraday's currents that speed from place to +place through these wires. Approaching the point of Dungeness, the +mariner sees an unusually brilliant light, and from the noble lighthouse +of La Hève the same light flashes across the sea. These are Faraday's +sparks exalted by suitable machinery to sun-like splendour. At the +present moment the Board of Trade and the Brethren of the Trinity House, +as well as the Commissioners of Northern Lights, are contemplating the +introduction of the Magneto-electric Light at numerous points upon our +coasts; and future generations will be able to refer to those guiding +stars in answer to the question, what has been the practical use of the +labours of Faraday? But I would again emphatically say, that his work +needs no justification, and that if he had allowed his vision to be +disturbed by considerations regarding the practical use of his +discoveries, those discoveries would never have been made by him. "I +have rather," he writes in 1831, "been desirous of discovering new facts +and new relations dependent on magneto-electric induction, than of +exalting the force of those already obtained; being assured that the +latter would find their full development hereafter." + +In 1817, when lecturing before a private society in London on the +element chlorine, Faraday thus expresses himself with reference to this +question of utility. "Before leaving this subject, I will point out the +history of this substance as an answer to those who are in the habit of +saying to every new fact, 'What is its use?' Dr. Franklin says to such, +'What is the use of an infant?' The answer of the experimentalist is, +'Endeavour to make it useful.' When Scheele discovered this substance, +it appeared to have no use; it was in its infancy and useless state, but +having grown up to maturity, witness its powers, and see what endeavours +to make it useful have done." + + + + +PROFESSOR JOSEPH HENRY'S INVENTION OF THE ELECTRIC TELEGRAPH + + [In 1855 the Regents of the Smithsonian Institution, Washington, D. + C., at the instance of their secretary, Professor Joseph Henry, + took evidence with respect to his claims as inventor of the + electric telegraph. The essential paragraphs of Professor Henry's + statement are taken from the Proceedings of the Board of Regents of + the Smithsonian Institution, Washington, 1857.] + + +There are several forms of the electric telegraph; first, that in which +frictional electricity has been proposed to produce sparks and motion of +pith balls at a distance. + +Second, that in which galvanism has been employed to produce signals by +means of bubbles of gas from the decomposition of water. + +Third, that in which electro-magnetism is the motive power to produce +motion at a distance; and again, of the latter there are two kinds of +telegraphs, those in which the intelligence is indicated by the motion +of a magnetic needle, and those in which sounds and permanent signs are +made by the attraction of an electro-magnet. The latter is the class to +which Mr. Morse's invention belongs. The following is a brief exposition +of the several steps which led to this form of the telegraph. + +The first essential fact which rendered the electro-magnetic telegraph +possible was discovered by Oersted, in the winter of 1819-'20. It is +illustrated by figure 1, in which the magnetic needle is deflected by +the action of a current of galvanism transmitted through the wire A B. + +[Illustration: Fig. 1] + +The second fact of importance, discovered in 1820, by Arago and Davy, is +illustrated in Fig. 2. It consists in this, that while a current of +galvanism is passing through a copper wire A B, it is magnetic, it +attracts iron filings and not those of copper or brass, and is capable +of developing magnetism in soft iron. + +[Illustration: Fig. 2] + +The next important discovery, also made in 1820, by Ampère, was that two +wires through which galvanic currents are passing in the same direction +attract, and in the opposite direction, repel, each other. On this fact +Ampère founded his celebrated theory, that magnetism consists merely in +the attraction of electrical currents revolving at right angles to the +line joining the two poles of the magnet. The magnetization of a bar of +steel or iron, according to this theory consists in establishing within +the metal by induction a series of electrical currents, all revolving in +the same direction at right angles to the axis or length of the bar. + +[Illustration: Fig. 3] + +It was this theory which led Arago, as he states, to adopt the method of +magnetizing sewing needles and pieces of steel wire, shown in Fig. 3. +This method consists in transmitting a current of electricity through a +helix surrounding the needle or wire to be magnetised. For the purpose +of insulation the needle was enclosed in a glass tube, and the several +turns of the helix were at a distance from each other to insure the +passage of electricity through the whole length of the wire, or, in +other words, to prevent it from seeking a shorter passage by cutting +across from one spire to another. The helix employed by Arago obviously +approximates the arrangement required by the theory of Ampère, in order +to develop by induction the magnetism of the iron. By an attentive +perusal of the original account of the experiments of Arago, it will be +seen that, properly speaking, he made no electro-magnet, as has been +asserted by Morse and others; his experiments were confined to the +magnetism of iron filings, to sewing needles and pieces of steel wire of +the diameter of a millimetre, or of about the thickness of a small +knitting needle. + +[Illustration: Fig. 4] + +Mr. Sturgeon, in 1825, made an important step in advance of the +experiments of Arago, and produced what is properly known as the +electro-magnet. He bent a piece of iron _wire_ into the form of a +horseshoe, covered it with varnish to insulate it, and surrounded it +with a helix, of which the spires were at a distance. When a current of +galvanism was passed through the helix from a small battery of a single +cup the iron wire became magnetic, and continued so during the passage +of the current. When the current was interrupted the magnetism +disappeared, and thus was produced the first temporary soft iron +magnet. + +The electro-magnet of Sturgeon is shown in Fig. 4. By comparing Figs. 3 +and 4 it will be seen that the helix employed by Sturgeon was of the +same kind as that used by Arago; instead however, of a straight steel +wire inclosed in a tube of glass, the former employed a bent wire of +soft iron. The difference in the arrangement at first sight might appear +to be small, but the difference in the results produced was important, +since the temporary magnetism developed in the arrangement of Sturgeon +was sufficient to support a weight of several pounds, and an instrument +was thus produced of value in future research. + +[Illustration: Fig. 5] + +The next improvement was made by myself. After reading an account of the +galvanometer of Schweigger, the idea occurred to me that a much nearer +approximation to the requirements of the theory of Ampère could be +attained by insulating the conducting wire itself, instead of the rod to +be magnetized, and by covering the whole surface of the iron with a +series of coils in close contact. This was effected by insulating a long +wire with silk thread, and winding this around the rod of iron in close +coils from one end to the other. The same principle was extended by +employing a still longer insulated wire, and winding several strata of +this over the first, care being taken to insure the insulation between +each stratum by a covering of silk ribbon. By this arrangement the rod +was surrounded by a compound helix formed of a long wire of many coils, +instead of a single helix of a few coils, (Fig. 5). + +In the arrangement of Arago and Sturgeon the several turns of wire were +not precisely at right angles to the axis of the rod, as they should be, +to produce the effect required by the theory, but slightly oblique, and +therefore each tended to develop a separate magnetism not coincident +with the axis of the bar. But in winding the wire over itself, the +obliquity of the several turns compensated each other, and the resultant +action was at right angles to the bar. The arrangement then introduced +by myself was superior to those of Arago and Sturgeon, first in the +greater multiplicity of turns of wire, and second in the better +application of these turns to the development of magnetism. The power of +the instrument with the same amount of galvanic force, was by this +arrangement several times increased. + +The maximum effect, however, with this arrangement and a single battery +was not yet obtained. After a certain length of wire had been coiled +upon the iron, the power diminished with a further increase of the +number of turns. This was due to the increased resistance which the +longer wire offered to the conduction of electricity. Two methods of +improvement therefore suggested themselves. The first consisted, not in +increasing the length of the coil, but in using a number of separate +coils on the same piece of iron. By this arrangement the resistance to +the conduction of the electricity was diminished and a greater quantity +made to circulate around the iron from the same battery. The second +method of producing a similar result consisted in increasing the number +of elements of the battery, or, in other words, the projectile force of +the electricity, which enabled it to pass through an increased number of +turns of wire, and thus, by increasing the length of the wire, to +develop the maximum power of the iron. + +[Illustration: Fig. 6] + +To test these principles on a larger scale, the experimental magnet was +constructed, which is shown in Fig. 6. In this a number of compound +helices were placed on the same bar, their ends left projecting, and so +numbered that they could be all united into one long helix, or variously +combined in sets of lesser length. + +From a series of experiments with this and other magnets it was proved +that, in order to produce the greatest amount of magnetism from a +battery of a single cup, a number of helices is required; but when a +compound battery is used, then one long wire must be employed, making +many turns around the iron, the length of wire and consequently the +number of turns being commensurate with the projectile power of the +battery. + +In describing the results of my experiments, the terms _intensity_ and +_quantity_ magnets were introduced to avoid circumlocution, and were +intended to be used merely in a technical sense. By the _intensity_ +magnet I designated a piece of soft iron, so surrounded with wire that +its magnetic power could be called into operation by an _intensity_ +battery, and by a _quantity_ magnet, a piece of iron so surrounded by a +number of separate coils, that its magnetism could be fully developed by +a _quantity_ battery. + +I was the first to point out this connection of the two kinds of the +battery with the two forms of the magnet, in my paper in _Silliman's +Journal_, January, 1831, and clearly to state that when magnetism was to +be developed by means of a compound battery, one long coil was to be +employed, and when the maximum effect was to be produced by a single +battery, a number of single strands were to be used. + +These steps in the advance of electro-magnetism, though small, were such +as to interest and astonish the scientific world. With the same battery +used by Mr. Sturgeon, at least a hundred times more magnetism was +produced than could have been obtained by his experiment. The +developments were considered at the time of much importance in a +scientific point of view, and they subsequently furnished the means by +which magneto-electricity, the phenomena of dia-magnetism, and the +magnetic effects on polarized light were discovered. They gave rise to +the various forms of electro-magnetic machines which have since +exercised the ingenuity of inventors in every part of the world, and +were of immediate applicability in the introduction of the magnet to +telegraphic purposes. Neither the electro-magnet of Sturgeon nor any +electro-magnet ever made previous to my investigations was applicable to +transmitting power to a distance. + +The principles I have developed were properly appreciated by the +scientific mind of Dr. Gale, and applied by him to operate Mr. Morse's +machine at a distance. + +Previous to my investigations the means of developing magnetism in soft +iron were imperfectly understood. The electro-magnet made by Sturgeon, +and copied by Dana, of New York, was an imperfect quantity magnet, the +feeble power of which was developed by a single battery. It was entirely +inapplicable to a long circuit with an intensity battery, and no person +possessing the requisite scientific knowledge, would have attempted to +use it in that connection after reading my paper. + +In sending a message to a distance, two circuits are employed, the +first a long circuit through which the electricity is sent to the +distant station to bring into action the second, a short one, in which +is the local battery and magnet for working the machine. In order to +give projectile force sufficient to send the power to a distance, it is +necessary to use an intensity battery in the long circuit, and in +connection with this, at the distant station, a magnet surrounded with +many turns of one long wire must be employed to receive and multiply the +effect of the current enfeebled by its transmission through the long +conductor. In the local or short circuit either an intensity or a +quantity magnet may be employed. If the first be used, then with it a +compound battery will be required; and, therefore on account of the +increased resistance due to the greater quantity of acid, a less amount +of work will be performed by a given amount of material; and, +consequently, though this arrangement is practicable it is by no means +economical. In my original paper I state that the advantages of a +greater conducting power, from using several wires in the quantity +magnet, may, in a less degree, be obtained by substituting for them one +large wire; but in this case, on account of the greater obliquity of the +spires and other causes, the magnetic effect would be less. In +accordance with these principles, the receiving magnet, or that which is +introduced into the long circuit, consists of a horseshoe magnet +surrounded with many hundred turns of a single long wire, and is +operated with a battery of from twelve to twenty-four elements or more, +while in the local circuit it is customary to employ a battery of one or +two elements with a much thicker wire and fewer turns. + +It will, I think, be evident to the impartial reader that these were +improvements in the electro-magnet, which first rendered it adequate to +the transmission of mechanical power to a distance; and had I omitted +all allusion to the telegraph in my paper, the conscientious historian +of science would have awarded me some credit, however small might have +been the advance which I made. Arago and Sturgeon, in the accounts of +their experiments, make no mention of the telegraph, and yet their names +always have been and will be associated with the invention. I briefly, +however, called attention to the fact of the applicability of my +experiments to the construction of the telegraph; but not being familiar +with the history of the attempts made in regard to this invention, I +called it "Barlow's project," while I ought to have stated that Mr. +Barlow's investigation merely tended to disprove the possibility of a +telegraph. + +I did not refer exclusively to the needle telegraph when, in my paper, I +stated that the _magnetic_ action of a current from a trough is at least +not sensibly diminished by passing through a long wire. This is evident +from the fact that the immediate experiment from which this deduction +was made was by means of an electro-magnet and not by means of a needle +galvanometer. + +[Illustration: Fig. 7] + +At the conclusion of the series of experiments which I described in +_Silliman's Journal_, there were two applications of the electro-magnet +in my mind: one the production of a machine to be moved by +electro-magnetism, and the other the transmission of or calling into +action power at a distance. The first was carried into execution in the +construction of the machine described in _Silliman's Journal_, vol. xx, +1831, and for the purpose of experimenting in regard to the second, I +arranged around one of the upper rooms in the Albany Academy a wire of +more than a mile in length, through which I was enabled to make signals +by sounding a bell, (Fig. 7.) The mechanical arrangement for effecting +this object was simply a steel bar, permanently magnetized, of about ten +inches in length, supported on a pivot, and placed with its north end +between the two arms of a horseshoe magnet. When the latter was excited +by the current, the end of the bar thus placed was attracted by one arm +of the horseshoe, and repelled by the other, and was thus caused to move +in a horizontal plane and its further extremity to strike a bell +suitably adjusted. + +I also devised a method of breaking a circuit, and thereby causing a +large weight to fall. It was intended to illustrate the practicability +of calling into action a great power at a distance capable of producing +mechanical effects; but as a description of this was not printed, I do +not place it in the same category with the experiments of which I +published an account, or the facts which could be immediately deduced +from my papers in _Silliman's Journal_. + +From a careful investigation of the history of electro-magnetism in its +connection with the telegraph, the following facts may be established: + +1. Previous to my investigations the means of developing magnetism in +soft iron were imperfectly understood, and the electro-magnet which then +existed was inapplicable to the transmission of power to a distance. + +2. I was the first to prove by actual experiment that, in order to +develop magnetic power at a distance, a galvanic battery of intensity +must be employed to project the current through the long conductor, and +that a magnet surrounded by many turns of one long wire must be used to +receive this current. + +3. I was the first actually to magnetize a piece of iron at a distance, +and to call attention to the fact of the applicability of my experiments +to the telegraph. + +4. I was the first to actually sound a bell at a distance by means of +the electro-magnet. + +5. The principles I had developed were applied by Dr. Gale to render +Morse's machine effective at a distance. + + + + +THE FIRST ATLANTIC CABLES + +GEORGE ILES + + [From "Flame, Electricity and the Camera," copyright Doubleday, + Page & Co., New York.] + + +Electric telegraphy on land has put a vast distance between itself and +the mechanical signalling of Chappé, just as the scope and availability +of the French invention are in high contrast with the rude signal fires +of the primitive savage. As the first land telegraphs joined village to +village, and city to city, the crossing of water came in as a minor +incident; the wires were readily committed to the bridges which spanned +streams of moderate width. Where a river or inlet was unbridged, or a +channel was too wide for the roadway of the engineer, the question +arose, May we lay an electric wire under water? With an ordinary land +line, air serves as so good a non-conductor and insulator that as a rule +cheap iron may be employed for the wire instead of expensive copper. In +the quest for non-conductors suitable for immersion in rivers, channels, +and the sea, obstacles of a stubborn kind were confronted. To overcome +them demanded new materials, more refined instruments, and a complete +revision of electrical philosophy. + +As far back as 1795, Francisco Salva had recommended to the Academy of +Sciences, Barcelona, the covering of subaqueous wires by resin, which +is both impenetrable by water and a non-conductor of electricity. +Insulators, indeed, of one kind and another, were common enough, but +each of them was defective in some quality indispensable for success. +Neither glass nor porcelain is flexible, and therefore to lay a +continuous line of one or the other was out of the question. Resin and +pitch were even more faulty, because extremely brittle and friable. What +of such fibres as hemp or silk, if saturated with tar or some other good +non-conductor? For very short distances under still water they served +fairly well, but any exposure to a rocky beach with its chafing action, +any rub by a passing anchor, was fatal to them. What the copper wire +needed was a covering impervious to water, unchangeable in composition +by time, tough of texture, and non-conducting in the highest degree. +Fortunately all these properties are united in gutta-percha: they exist +in nothing else known to art. Gutta-percha is the hardened juice of a +large tree (_Isonandra gutta_) common in the Malay Archipelago; it is +tough and strong, easily moulded when moderately heated. In comparison +with copper it is but one 60,000,000,000,000,000,000th as conductive. As +without gutta-percha there could be no ocean telegraphy, it is worth +while recalling how it came within the purview of the electrical +engineer. + +In 1843 José d'Almeida, a Portuguese engineer, presented to the Royal +Asiatic Society, London, the first specimens of gutta-percha brought to +Europe. A few months later, Dr. W. Montgomerie, a surgeon, gave other +specimens to the Society of Arts, of London, which exhibited them; but +it was four years before the chief characteristic of the gum was +recognized. In 1847 Mr. S. T. Armstrong of New York, during a visit to +London, inspected a pound or two of gutta-percha, and found it to be +twice as good a non-conductor as glass. The next year, through his +instrumentality, a cable covered with this new insulator was laid +between New York and Jersey City; its success prompted Mr Armstrong to +suggest that a similarly protected cable be submerged between America +and Europe. Eighteen years of untiring effort, impeded by the errors +inevitable to the pioneer, stood between the proposal and its +fulfilment. In 1848 the Messrs. Siemens laid under water in the port of +Kiel a wire covered with seamless gutta-percha, such as, beginning with +1847, they had employed for subterranean conductors. This particular +wire was not used for telegraphy, but formed part of a submarine-mine +system. In 1849 Mr. C. V. Walker laid an experimental line in the +English Channel; he proved the possibility of signalling for two miles +through a wire covered with gutta-percha, and so prepared the way for a +venture which joined the shores of France and England. + +[Illustration: Fig. 58.--Calais-Dover cable, 1851] + +In 1850 a cable twenty-five miles in length was laid from Dover to +Calais, only to prove worthless from faulty insulation and the lack of +armour against dragging anchors and fretting rocks. In 1851 the +experiment was repeated with success. The conductor now was not a single +wire of copper, but four wires, wound spirally, so as to combine +strength with flexibility; these were covered with gutta-percha and +surrounded with tarred hemp. As a means of imparting additional +strength, ten iron wires were wound round the hemp--a feature which has +been copied in every subsequent cable (Fig. 58). The engineers were fast +learning the rigorous conditions of submarine telegraphy; in its +essentials the Dover-Calais line continues to be the type of deep-sea +cables to-day. The success of the wire laid across the British Channel +incited other ventures of the kind. Many of them, through careless +construction or unskilful laying, were utter failures. At last, in 1855, +a submarine line 171 miles in length gave excellent service, as it +united Varna with Constantinople; this was the greatest length of +satisfactory cable until the submergence of an Atlantic line. + +In 1854 Cyrus W. Field of New York opened a new chapter in electrical +enterprise as he resolved to lay a cable between Ireland and +Newfoundland, along the shortest line that joins Europe to America. He +chose Valentia and Heart's Content, a little more than 1,600 miles +apart, as his termini, and at once began to enlist the co-operation of +his friends. Although an unfaltering enthusiast when once his great idea +had possession of him, Mr. Field was a man of strong common sense. From +first to last he went upon well-ascertained facts; when he failed he did +so simply because other facts, which he could not possibly know, had to +be disclosed by costly experience. Messrs. Whitehouse and Bright, +electricians to his company, were instructed to begin a preliminary +series of experiments. They united a continuous stretch of wires laid +beneath land and water for a distance of 2,000 miles, and found that +through this extraordinary circuit they could transmit as many as four +signals per second. They inferred that an Atlantic cable would offer but +little more resistance, and would therefore be electrically workable and +commercially lucrative. + +In 1857 a cable was forthwith manufactured, divided in halves, and +stowed in the holds of the _Niagara_ of the United States navy, and the +_Agamemnon_ of the British fleet. The _Niagara_ sailed from Ireland; the +sister ship proceeded to Newfoundland, and was to meet her in mid-ocean. +When the _Niagara_ had run out 335 miles of her cable it snapped under +a sudden increase of strain at the paying-out machinery; all attempts at +recovery were unavailing, and the work for that year was abandoned. The +next year it was resumed, a liberal supply of new cable having been +manufactured to replace the lost section, and to meet any fresh +emergency that might arise. A new plan of voyages was adopted: the +vessels now sailed together to mid-sea, uniting there both portions of +the cable; then one ship steamed off to Ireland, the other to the +Newfoundland coast. Both reached their destinations on the same day, +August 5, 1858, and, feeble and irregular though it was, an electric +pulse for the first time now bore a message from hemisphere to +hemisphere. After 732 despatches had passed through the wire it became +silent forever. In one of these despatches from London, the War Office +countermanded the departure of two regiments about to leave Canada for +England, which saved an outlay of about $250,000. This widely quoted +fact demonstrated with telling effect the value of cable telegraphy. + +Now followed years of struggle which would have dismayed any less +resolute soul than Mr. Field. The Civil War had broken out, with its +perils to the Union, its alarms and anxieties for every American heart. +But while battleships and cruisers were patrolling the coast from Maine +to Florida, and regiments were marching through Washington on their way +to battle, there was no remission of effort on the part of the great +projector. + +Indeed, in the misunderstandings which grew out of the war, and that at +one time threatened international conflict, he plainly saw how a cable +would have been a peace-maker. A single word of explanation through its +wire, and angry feelings on both sides of the ocean would have been +allayed at the time of the _Trent_ affair. In this conviction he was +confirmed by the English press; the London _Times_ said: "We nearly went +to war with America because we had no telegraph across the Atlantic." In +1859 the British government had appointed a committee of eminent +engineers to inquire into the feasibility of an Atlantic telegraph, with +a view to ascertaining what was wanting for success, and with the +intention of adding to its original aid in case the enterprise were +revived. In July, 1863, this committee presented a report entirely +favourable in its terms, affirming "that a well-insulated cable, +properly protected, of suitable specific gravity, made with care, tested +under water throughout its progress with the best-known apparatus, and +paid into the ocean with the most improved machinery, possesses every +prospect of not only being successfully laid in the first instance, but +may reasonably be relied upon to continue for many years in an efficient +state for the transmission of signals." + +Taking his stand upon this endorsement, Mr. Field now addressed himself +to the task of raising the large sum needed to make and lay a new cable +which should be so much better than the old ones as to reward its owners +with triumph. He found his English friends willing to venture the +capital required, and without further delay the manufacture of a new +cable was taken in hand. In every detail the recommendations of the +Scientific Committee were carried out to the letter, so that the cable +of 1865 was incomparably superior to that of 1858. First, the central +copper wire, which was the nerve along which the lightning was to run, +was nearly three times larger than before. The old conductor was a +strand consisting of seven fine wires, six laid around one, and weighed +but 107 pounds to the mile. The new was composed of the same number of +wires, but weighed 300 pounds to the mile. It was made of the finest +copper obtainable. + +To secure insulation, this conductor was first embedded in Chatterton's +compound, a preparation impervious to water, and then covered with four +layers of gutta-percha, which were laid on alternately with four thin +layers of Chatterton's compound. The old cable had but three coatings of +gutta-percha, with nothing between. Its entire insulation weighed but +261 pounds to the mile, while that of the new weighed 400 pounds.[1] The +exterior wires, ten in number, were of Bessemer steel, each separately +wound in pitch-soaked hemp yarn, the shore ends specially protected by +thirty-six wires girdling the whole. Here was a combination of the +tenacity of steel with much of the flexibility of rope. The insulation +of the copper was so excellent as to exceed by a hundredfold that of the +core of 1858--which, faulty though it was, had, nevertheless, sufficed +for signals. So much inconvenience and risk had been encountered in +dividing the task of cable-laying between two ships that this time it +was decided to charter a single vessel, the _Great Eastern_, which, +fortunately, was large enough to accommodate the cable in an unbroken +length. Foilhommerum Bay, about six miles from Valentia, was selected as +the new Irish terminus by the company. Although the most anxious care +was exercised in every detail, yet, when 1,186 miles had been laid, the +cable parted in 11,000 feet of water, and although thrice it was +grappled and brought toward the surface, thrice it slipped off the +grappling hooks and escaped to the ocean floor. Mr. Field was obliged to +return to England and face as best he might the men whose capital lay at +the bottom of the sea--perchance as worthless as so much Atlantic ooze. +With heroic persistence he argued that all difficulties would yield to a +renewed attack. There must be redoubled precautions and vigilance never +for a moment relaxed. Everything that deep-sea telegraphy has since +accomplished was at that moment daylight clear to his prophetic view. +Never has there been a more signal example of the power of enthusiasm to +stir cold-blooded men of business; never has there been a more striking +illustration of how much science may depend for success upon the +intelligence and the courage of capital. Electricians might have gone on +perfecting exquisite apparatus for ocean telegraphy, or indicated the +weak points in the comparatively rude machinery which made and laid the +cable, yet their exertions would have been wasted if men of wealth had +not responded to Mr. Field's renewed appeal for help. Thrice these men +had invested largely, and thrice disaster had pursued their ventures; +nevertheless they had faith surviving all misfortunes for a fourth +attempt. + +In 1866 a new company was organized, for two objects: first, to recover +the cable lost the previous year and complete it to the American shore; +second, to lay another beside it in a parallel course. The _Great +Eastern_ was again put in commission, and remodelled in accordance with +the experience of her preceding voyage. This time the exterior wires of +the cable were of galvanized iron, the better to resist corrosion. The +paying-out machinery was reconstructed and greatly improved. On July 13, +1866, the huge steamer began running out her cable twenty-five miles +north of the line struck out during the expedition of 1865; she arrived +without mishap in Newfoundland on July 27, and electrical communication +was re-established between America and Europe. The steamer now returned +to the spot where she had lost the cable a few months before; after +eighteen days' search it was brought to the deck in good order. Union +was effected with the cable stowed in the tanks below, and the prow of +the vessel was once more turned to Newfoundland. On September 8th this +second cable was safely landed at Trinity Bay. Misfortunes now were at +an end; the courage of Mr. Field knew victory at last; the highest +honors of two continents were showered upon him. + + 'Tis not the grapes of Canaan that repay, + But the high faith that failed not by the way. + +[Illustration: Fig. 59.--Commercial cable, 1894] + +What at first was as much a daring adventure as a business enterprise +has now taken its place as a task no more out of the common than +building a steamship, or rearing a cantilever bridge. Given its price, +which will include too moderate a profit to betray any expectation of +failure, and a responsible firm will contract to lay a cable across the +Pacific itself. In the Atlantic lines the uniformly low temperature of +the ocean floor (about 4° C.), and the great pressure of the +superincumbent sea, co-operate in effecting an enormous enhancement both +in the insulation and in the carrying capacity of the wire. As an +example of recent work in ocean telegraphy let us glance at the cable +laid in 1894, by the Commercial Cable Company of New York. It unites +Cape Canso, on the northeastern coast of Nova Scotia, to Waterville, on +the southwestern coast of Ireland. The central portion of this cable +much resembles that of its predecessor in 1866. Its exterior armour of +steel wires is much more elaborate. The first part of Fig. 59 shows the +details of manufacture: the central copper core is covered with +gutta-percha, then with jute, upon which the steel wires are spirally +wound, followed by a strong outer covering. For the greatest depths at +sea, type _A_ is employed for a total length of 1,420 miles; the +diameter of this part of the cable is seven-eighths of an inch. As the +water lessens in depth the sheathing increases in size until the +diameter of the cable becomes one and one-sixteenth inches for 152 +miles, as type _B_. The cable now undergoes a third enlargement, and +then its fourth and last proportions are presented as it touches the +shore, for a distance of one and three-quarter miles, where type _C_ has +a diameter of two and one-half inches. The weights of material used in +this cable are: copper wire, 495 tons; gutta-percha, 315 tons; jute +yarn, 575 tons; steel wire, 3,000 tons; compound and tar, 1,075 tons; +total, 5,460 tons. The telegraph-ship _Faraday_, specially designed for +cable-laying, accomplished the work without mishap. + +Electrical science owes much to the Atlantic cables, in particular to +the first of them. At the very beginning it banished the idea that +electricity as it passes through metallic conductors has anything like +its velocity through free space. It was soon found, as Professor +Mendenhall says, "that it is no more correct to assign a definite +velocity to electricity than to a river. As the rate of flow of a river +is determined by the character of its bed, its gradient, and other +circumstances, so the velocity of an electric current is found to depend +on the conditions under which the flow takes place."[2] Mile for mile +the original Atlantic cable had twenty times the retarding effect of a +good aerial line; the best recent cables reduce this figure by nearly +one-half. + +In an extreme form, this slowing down reminds us of the obstruction of +light as it enters the atmosphere of the earth, of the further +impediment which the rays encounter if they pass from the air into the +sea. In the main the causes which hinder a pulse committed to a cable +are two: induction, and the electrostatic capacity of the wire, that is, +the capacity of the wire to take up a charge of its own, just as if it +were the metal of a Leyden jar. + +Let us first consider induction. As a current takes its way through the +copper core it induces in its surroundings a second and opposing +current. For this the remedy is one too costly to be applied. Were a +cable manufactured in a double line, as in the best telephonic circuits, +induction, with its retarding and quenching effects, would be +neutralized. Here the steel wire armour which encircles the cable plays +an unwelcome part. Induction is always proportioned to the conductivity +of the mass in which it appears; as steel is an excellent conductor, the +armour of an ocean cable, close as it is to the copper core, has induced +in it a current much stronger, and therefore more retarding, than if the +steel wire were absent. + +A word now as to the second difficulty in working beneath the sea--that +due to the absorbing power of the line itself. An Atlantic cable, like +any other extended conductor, is virtually a long, cylindrical Leyden +jar, the copper wire forming the inner coat, and its surroundings the +outer coat. Before a signal can be received at the distant terminus the +wire must first be charged. The effect is somewhat like transmitting a +signal through water which fills a rubber tube; first of all the tube +is distended, and its compression, or secondary effect, really transmits +the impulse. A remedy for this is a condenser formed of alternate sheets +of tin-foil and mica, _C_, connected with the battery, _B_, so as to +balance the electric charge of the cable wire (Fig. 60). In the first +Atlantic line an impulse demanded one-seventh of a second for its +journey. This was reduced when Mr. Whitehouse made the capital discovery +that the speed of a signal is increased threefold when the wire is +alternately connected with the zinc and copper poles of the battery. Sir +William Thomson ascertained that these successive pulses are most +effective when of proportioned lengths. He accordingly devised an +automatic transmitter which draws a duly perforated slip of paper under +a metallic spring connected with the cable. To-day 250 to 300 letters +are sent per minute instead of fifteen, as at first. + +[Illustration: Fig. 60.--Condenser] + +In many ways a deep-sea cable exaggerates in an instructive manner the +phenomena of telegraphy over long aerial lines. The two ends of a cable +may be in regions of widely diverse electrical potential, or pressure, +just as the readings of the barometer at these two places may differ +much. If a copper wire were allowed to offer itself as a gateless +conductor it would equalize these variations of potential with serious +injury to itself. Accordingly the rule is adopted of working the cable +not directly, as if it were a land line, but indirectly through +condensers. As the throb sent through such apparatus is but momentary, +the cable is in no risk from the strong currents which would course +through it if it were permitted to be an open channel. + +[Illustration: Fig. 61.--Reflecting galvanometer L, lamp; N, moving spot +of light reflected from mirror] + +A serious error in working the first cables was in supposing that they +required strong currents as in land lines of considerable length. The +very reverse is the fact. Mr. Charles Bright, in _Submarine Telegraphs_, +says: + +"Mr. Latimer Clark had the conductor of the 1865 and 1866 lines joined +together at the Newfoundland end, thus forming an unbroken length of +3,700 miles in circuit. He then placed some sulphuric acid in a very +small silver thimble, with a fragment of zinc weighing a grain or two. +By this primitive agency he succeeded in conveying signals through twice +the breadth of the Atlantic Ocean in little more than a second of time +after making contact. The deflections were not of a dubious character, +but full and strong, from which it was manifest than an even smaller +battery would suffice to produce somewhat similar effects." + +[Illustration: Fig. 62.--Siphon recorder] + +At first in operating the Atlantic cable a mirror galvanometer was +employed as a receiver. The principle of this receiver has often been +illustrated by a mischievous boy as, with a slight and almost +imperceptible motion of his hand, he has used a bit of looking-glass to +dart a ray of reflected sunlight across a wide street or a large room. +On the same plan, the extremely minute motion of a galvanometer, as it +receives the successive pulsations of a message, is magnified by a +weightless lever of light so that the words are easily read by an +operator (Fig. 61). This beautiful invention comes from the hands of Sir +William Thomson [now Lord Kelvin], who, more than any other electrician, +has made ocean telegraphy an established success. + +[Illustration: Fig. 63.--Siphon record. "Arrived yesterday"] + +In another receiver, also of his design, the siphon recorder, he began +by taking advantage of the fact, observed long before by Bose, that a +charge of electricity stimulates the flow of a liquid. In its original +form the ink-well into which the siphon dipped was insulated and charged +to a high voltage by an influence-machine; the ink, powerfully repelled, +was spurted from the siphon point to a moving strip of paper beneath +(Fig. 62). It was afterward found better to use a delicate mechanical +shaker which throws out the ink in minute drops as the cable current +gently sways the siphon back and forth (Fig. 63). + +Minute as the current is which suffices for cable telegraphy, it is +essential that the metallic circuit be not only unbroken, but unimpaired +throughout. No part of his duty has more severely taxed the resources of +the electrician than to discover the breaks and leaks in his ocean +cables. One of his methods is to pour electricity as it were, into a +broken wire, much as if it were a narrow tube, and estimate the length +of the wire (and consequently the distance from shore to the defect or +break) by the quantity of current required to fill it. + + +FOOTNOTES: + +[1] Henry M. Field, "History of the Atlantic Telegraph." New York: +Scribner, 1866. + +[2] "A Century of Electricity." Boston, Houghton, Mifflin & Co., 1887. + + + + +BELL'S TELEPHONIC RESEARCHES + + [From "Bell's Electric Speaking Telephones," by George B. Prescott, + copyright by D Appleton & Co., New York, 1884] + + +In a lecture delivered before the Society of Telegraph Engineers, in +London, October 31, 1877, Prof. A. G. Bell gave a history of his +researches in telephony, together with the experiments that he was led +to undertake in his endeavours to produce a practical system of multiple +telegraphy, and to realize also the transmission of articulate speech. +After the usual introduction, Professor Bell said in part: + +It is to-night my pleasure, as well as duty, to give you some account of +the telephonic researches in which I have been so long engaged. Many +years ago my attention was directed to the mechanism of speech by my +father, Alexander Melville Bell, of Edinburgh, who has made a life-long +study of the subject. Many of those present may recollect the invention +by my father of a means of representing, in a wonderfully accurate +manner, the positions of the vocal organs in forming sounds. Together we +carried on quite a number of experiments, seeking to discover the +correct mechanism of English and foreign elements of speech, and I +remember especially an investigation in which we were engaged +concerning the musical relations of vowel sounds. When vocal sounds are +whispered, each vowel seems to possess a particular pitch of its own, +and by whispering certain vowels in succession a musical scale can be +distinctly perceived. Our aim was to determine the natural pitch of each +vowel; but unexpected difficulties made their appearance, for many of +the vowels seemed to possess a double pitch--one due, probably, to the +resonance of the air in the mouth, and the other to the resonance of the +air contained in the cavity behind the tongue, comprehending the pharynx +and larynx. + +I hit upon an expedient for determining the pitch, which, at that time, +I thought to be original with myself. It consisted in vibrating a tuning +fork in front of the mouth while the positions of the vocal organs for +the various vowels were silently taken. It was found that each vowel +position caused the reinforcement of some particular fork or forks. + +I wrote an account of these researches to Mr. Alex. J. Ellis, of London. +In reply, he informed me that the experiments related had already been +performed by Helmholtz, and in a much more perfect manner than I had +done. Indeed, he said that Helmholtz had not only analyzed the vowel +sounds into their constituent musical elements, but had actually +performed the synthesis of them. + +He had succeeded in producing, artificially, certain of the vowel sounds +by causing tuning forks of different pitch to vibrate simultaneously by +means of an electric current. Mr. Ellis was kind enough to grant me an +interview for the purpose of explaining the apparatus employed by +Helmholtz in producing these extraordinary effects, and I spent the +greater part of a delightful day with him in investigating the subject. +At that time, however, I was too slightly acquainted with the laws of +electricity fully to understand the explanations given; but the +interview had the effect of arousing my interest in the subjects of +sound and electricity, and I did not rest until I had obtained +possession of a copy of Helmholtz's great work "The Theory of Tone," and +had attempted, in a crude and imperfect manner, it is true, to reproduce +his results. While reflecting upon the possibilities of the production +of sound by electrical means, it struck me that the principle of +vibrating a tuning fork by the intermittent attraction of an +electro-magnet might be applied to the electrical production of music. + +I imagined to myself a series of tuning forks of different pitches, +arranged to vibrate automatically in the manner shown by Helmholtz--each +fork interrupting, at every vibration, a voltaic current--and the +thought occurred, Why should not the depression of a key like that of a +piano direct the interrupted current from any one of these forks, +through a telegraph wire, to a series of electro-magnets operating the +strings of a piano or other musical instrument, in which case a person +might play the tuning fork piano in one place and the music be audible +from the electro-magnetic piano in a distant city. + +The more I reflected upon this arrangement the more feasible did it seem +to me; indeed, I saw no reason why the depression of a number of keys at +the tuning fork end of the circuit should not be followed by the audible +production of a full chord from the piano in the distant city, each +tuning fork affecting at the receiving end that string of the piano with +which it was in unison. At this time the interest which I felt in +electricity led me to study the various systems of telegraphy in use in +this country and in America. I was much struck with the simplicity of +the Morse alphabet, and with the fact that it could be read by sound. +Instead of having the dots and dashes recorded on paper, the operators +were in the habit of observing the duration of the click of the +instruments, and in this way were enabled to distinguish by ear the +various signals. + +It struck me that in a similar manner the duration of a musical note +might be made to represent the dot or dash of the telegraph code, so +that a person might operate one of the keys of the tuning fork piano +referred to above, and the duration of the sound proceeding from the +corresponding string of the distant piano be observed by an operator +stationed there. It seemed to me that in this way a number of distinct +telegraph messages might be sent simultaneously from the tuning fork +piano to the other end of the circuit by operators, each manipulating a +different key of the instrument. These messages would be read by +operators stationed at the distant piano, each receiving operator +listening for signals for a certain definite pitch, and ignoring all +others. In this way could be accomplished the simultaneous transmission +of a number of telegraphic messages along a single wire, the number +being limited only by the delicacy of the listener's ear. The idea of +increasing the carrying power of a telegraph wire in this way took +complete possession of my mind, and it was this practical end that I had +in view when I commenced my researches in electric telephony. + +[Illustration: Fig. 1] + +In the progress of science it is universally found that complexity leads +to simplicity, and in narrating the history of scientific research it is +often advisable to begin at the end. + +In glancing back over my own researches, I find it necessary to +designate, by distinct names, a variety of electrical currents by means +of which sounds can be produced, and I shall direct your attention to +several distinct species of what may be termed telephonic currents of +electricity. In order that the peculiarities of these currents may be +clearly understood, I shall project upon the screen a graphical +illustration of the different varieties. + +The graphical method of representing electrical currents shown in Fig. 1 +is the best means I have been able to devise of studying, in an accurate +manner, the effects produced by various forms of telephonic apparatus, +and it has led me to the conception of that peculiar species of +telephonic current, here designated as _undulatory_, which has rendered +feasible the artificial production of articulate speech by electrical +means. + +A horizontal line (_g g'_) is taken as the zero of current, and impulses +of positive electricity are represented above the zero line, and +negative impulses below it, or _vice versa_. + +The vertical thickness of any electrical impulse (_b_ or _d_), measured +from the zero line, indicates the intensity of the electrical current at +the point observed; and the horizontal extension of the electric line +(_b_ or _d_) indicates the duration of the impulse. + +Nine varieties of telephonic currents may be distinguished, but it will +only be necessary to show you six of these. The three primary varieties +designated as intermittent, pulsatory and undulatory, are represented in +lines 1, 2 and 3. + +Sub-varieties of these can be distinguished as direct or reversed +currents, according as the electrical impulses are all of one kind or +are alternately positive and negative. Direct currents may still +further be distinguished as positive or negative, according as the +impulses are of one kind or of the other. + +An intermittent current is characterized by the alternate presence and +absence of electricity upon the circuit. + +A pulsatory current results from sudden or instantaneous changes in the +intensity of a continuous current; and + +An undulatory current is a current of electricity, the intensity of +which varies in a manner proportional to the velocity of the motion of a +particle of air during the production of a sound: thus the curve +representing graphically the undulatory current for a simple musical +note is the curve expressive of a simple pendulous vibration--that is, a +sinusoidal curve. + +And here I may remark, that, although the conception of the undulatory +current of electricity is entirely original with myself, methods of +producing sound by means of intermittent and pulsatory currents have +long been known. For instance, it was long since discovered that an +electro-magnet gives forth a decided sound when it is suddenly +magnetized or demagnetized. When the circuit upon which it is placed is +rapidly made and broken, a succession of explosive noises proceeds from +the magnet. These sounds produce upon the ear the effect of a musical +note when the current is interrupted a sufficient number of times per +second.... + +[Illustration: Fig. 2] + +For several years my attention was almost exclusively directed to the +production of an instrument for making and breaking a voltaic circuit +with extreme rapidity, to take the place of the transmitting tuning fork +used in Helmholtz's researches. Without going into details, I shall +merely say that the great defects of this plan of multiple telegraphy +were found to consist, first, in the fact that the receiving operators +were required to possess a good musical ear in order to discriminate the +signals; and secondly, that the signals could only pass in one direction +along the line (so that two wires would be necessary in order to +complete communication in both directions). The first objection was got +over by employing the device which I term a "vibratory circuit breaker," +whereby musical signals can be automatically recorded.... + +I have formerly stated that Helmholtz was enabled to produce vowel +sounds artificially by combining musical tones of different pitches and +intensities. His apparatus is shown in Fig. 2. Tuning forks of different +pitch are placed between the poles of electro-magnets (_a1_, _a2_, &c.), +and are kept in continuous vibration by the action of an intermittent +current from the fork _b_. Resonators, 1, 2, 3, etc., are arranged so as +to reinforce the sounds in a greater or less degree, according as the +exterior orifices are enlarged or contracted. + +[Illustration: Fig. 3] + +Thus it will be seen that upon Helmholtz's plan the tuning forks +themselves produce tones of uniform intensity, the loudness being varied +by an external reinforcement; but it struck me that the same results +would be obtained, and in a much more perfect manner, by causing the +tuning forks themselves to vibrate with different degrees of amplitude. +I therefore devised the apparatus shown in Fig. 3, which was my first +form of articulating telephone. In this figure a harp of steel rods is +employed, attached to the poles of a permanent magnet, N. S. When any +one of the rods is thrown into vibration an undulatory current is +produced in the coils of the electro-magnet E, and the electro-magnet E' +attracts the rods of the harp H' with a varying force, throwing into +vibration that rod which is in unison with that vibrating at the other +end of the circuit. Not only so, but the amplitude of vibration in the +one will determine the amplitude of vibration in the other, for the +intensity of the induced current is determined by the amplitude of the +inducing vibration, and the amplitude of the vibration at the receiving +end depends upon the intensity of the attractive impulses. When we sing +into a piano, certain of the strings of the instrument are set in +vibration sympathetically by the action of the voice with different +degrees of amplitude, and a sound, which is an approximation to the +vowel uttered, is produced from the piano. Theory shows that, had the +piano a very much larger number of strings to the octave, the vowel +sounds would be perfectly reproduced. My idea of the action of the +apparatus, shown in Fig. 3, was this: Utter a sound in the neighbourhood +of the harp H, and certain of the rods would be thrown into vibration +with different amplitudes. At the other end of the circuit the +corresponding rods of the harp H would vibrate with their proper +relations of force, and the _timbre_ [characteristic quality] of the +sound would be reproduced. The expense of constructing such an apparatus +as that shown in figure 3 deterred me from making the attempt, and I +sought to simplify the apparatus before venturing to have it made. + +[Illustration: Fig. 4] + +[Illustration: Fig. 5] + +[Illustration: Fig. 6] + +I have before alluded to the invention by my father of a system of +physiological symbols for representing the action of the vocal organs, +and I had been invited by the Boston Board of Education to conduct a +series of experiments with the system in the Boston school for the deaf +and dumb. It is well known that deaf mutes are dumb merely because they +are deaf, and that there is no defect in their vocal organs to +incapacitate them from utterance. Hence it was thought that my father's +system of pictorial symbols, popularly known as visible speech, might +prove a means whereby we could teach the deaf and dumb to use their +vocal organs and to speak. The great success of these experiments urged +upon me the advisability of devising method of exhibiting the vibrations +of sound optically, for use in teaching the deaf and dumb. For some time +I carried on experiments with the manometric capsule of Köenig and with +the phonautograph of Léon Scott. The scientific apparatus in the +Institute of Technology in Boston was freely placed at my disposal for +these experiments, and it happened that at that time a student of the +Institute of Technology, Mr. Maurey, had invented an improvement upon +the phonautograph. He had succeeded in vibrating by the voice a stylus +of wood about a foot in length, which was attached to the membrane of +the phonautograph, and in this way he had been enabled to obtain +enlarged tracings upon a plane surface of smoked glass. With this +apparatus I succeeded in producing very beautiful tracings of the +vibrations of the air for vowel sounds. Some of these tracings are shown +in Fig. 4. I was much struck with this improved form of apparatus, and +it occurred to me that there was a remarkable likeness between the +manner in which this piece of wood was vibrated by the membrane of the +phonautograph and the manner in which the _ossiculo_ [small bones] of +the human ear were moved by the tympanic membrane. I determined +therefore, to construct a phonautograph modelled still more closely +upon the mechanism of the human ear, and for this purpose I sought the +assistance of a distinguished aurist in Boston, Dr. Clarence J. Blake. +He suggested the use of the human ear itself as a phonautograph, instead +of making an artificial imitation of it. The idea was novel and struck +me accordingly, and I requested my friend to prepare a specimen for me, +which he did. The apparatus, as finally constructed, is shown in Fig. 5. +The _stapes_ [inmost of the three auditory ossicles] was removed and a +pointed piece of hay about an inch in length was attached to the end of +the incus [the middle of the three auditory ossicles]. Upon moistening +the membrana tympani [membrane of the ear drum] and the ossiculæ with a +mixture of glycerine and water the necessary mobility of the parts was +obtained, and upon singing into the external artificial ear the piece of +hay was thrown into vibration, and tracings were obtained upon a plane +surface of smoked glass passed rapidly underneath. While engaged in +these experiments I was struck with the remarkable disproportion in +weight between the membrane and the bones that were vibrated by it. It +occurred to me that if a membrane as thin as tissue paper could control +the vibration of bones that were, compared to it, of immense size and +weight, why should not a larger and thicker membrane be able to vibrate +a piece of iron in front of an electro-magnet, in which case the +complication of steel rods shown in my first form of telephone, Fig. 3, +could be done away with, and a simple piece of iron attached to a +membrane be placed at either end of the telegraphic circuit. + +Figure 6 shows the form of apparatus that I was then employing for +producing undulatory currents of electricity for the purpose of multiple +telegraphy. A steel reed, A, was clamped firmly by one extremity to the +uncovered leg _h_ of an electro-magnet E, and the free end of the reed +projected above the covered leg. When the reed A was vibrated in any +mechanical way the battery current was thrown into waves, and electrical +undulations traversed the circuit B E W E', throwing into vibration the +corresponding reed A' at the other end of the circuit. I immediately +proceeded to put my new idea to the test of practical experiment, and +for this purpose I attached the reed A (Fig. 7) loosely by one extremity +to the uncovered pole _h_ of the magnet, and fastened the other +extremity to the centre of a stretched membrane of goldbeaters' skin +_n_. I presumed that upon speaking in the neighbourhood of the membrane +_n_ it would be thrown into vibration and cause the steel reed A to move +in a similar manner, occasioning undulations in the electrical current +that would correspond to the changes in the density of the air during +the production of the sound; and I further thought that the change of +the density of the current at the receiving end would cause the magnet +there to attract the reed A' in such a manner that it should copy the +motion of the reed A, in which case its movements would occasion a sound +from the membrane _n'_ similar in _timbre_ to that which had occasioned +the original vibration. + +[Illustration: Fig. 7] + +[Illustration: Fig. 8] + +The results, however, were unsatisfactory and discouraging. My friend, +Mr. Thomas A. Watson, who assisted me in this first experiment, declared +that he heard a faint sound proceed from the telephone at his end of the +circuit, but I was unable to verify his assertion. After many +experiments, attended by the same only partially successful results, I +determined to reduce the size and weight of the spring as much as +possible. For this purpose I glued a piece of clock spring about the +size and shape of my thumb nail, firmly to the centre of the diaphragm, +and had a similar instrument at the other end (Fig. 8); we were then +enabled to obtain distinctly audible effects. I remember an experiment +made with this telephone, which at the time gave me great satisfaction +and delight. One of the telephones was placed in my lecture room in the +Boston University, and the other in the basement of the adjoining +building. One of my students repaired to the distant telephone to +observe the effects of articulate speech, while I uttered the sentence, +"Do you understand what I say?" into the telephone placed in the lecture +hall. To my delight an answer was returned through the instrument +itself, articulate sounds proceeded from the steel spring attached to +the membrane, and I heard the sentence, "Yes, I understand you +perfectly." It is a mistake, however, to suppose that the articulation +was by any means perfect, and expectancy no doubt had a great deal to do +with my recognition of the sentence; still, the articulation was there, +and I recognized the fact that the indistinctness was entirely due to +the imperfection of the instrument. I will not trouble you by detailing +the various stages through which the apparatus passed, but shall merely +say that after a time I produced the form of instrument shown in Fig. 9, +which served very well as a receiving telephone. In this condition my +invention was, in 1876, exhibited at the Centennial Exhibition in +Philadelphia. The telephone shown in Fig. 8 was used as a transmitting +instrument, and that in Fig. 9 as a receiver, so that vocal +communication was only established in one direction.... + +[Illustration: Fig. 9] + +The articulation produced from the instrument shown in Fig. 9 was +remarkably distinct, but its great defect consisted in the fact that it +could not be used as a transmitting instrument, and thus two telephones +were required at each station, one for transmitting and one for +receiving spoken messages. + +[Illustration: Fig. 10] + +It was determined to vary the construction of the telephone shown in +Fig. 8, and I sought, by changing the size and tension of the membrane, +the diameter and thickness of the steel spring, the size and power of +the magnet, and the coils of insulated wire around their poles, to +discover empirically the exact effect of each element of the +combination, and thus to deduce a more perfect form of apparatus. It was +found that a marked increase in the loudness of the sounds resulted from +shortening the length of the coils of wire, and by enlarging the iron +diaphragm which was glued to the membrane. In the latter case, also, the +distinctness of the articulation was improved. Finally, the membrane of +goldbeaters' skin was discarded entirely, and a simple iron plate was +used instead, and at once intelligible articulation was obtained. The +new form of instrument is that shown in Fig. 10, and, as had been long +anticipated, it was proved that the only use of the battery was to +magnetize the iron core, for the effects were equally audible when the +battery was omitted and a rod of magnetized steel substituted for the +iron core of the magnet. + +[Illustration: Fig. 11] + +It was my original intention, as shown in Fig. 3, and it was always +claimed by me, that the final form of telephone would be operated by +permanent magnets in place of batteries, and numerous experiments had +been carried on by Mr. Watson and myself privately for the purpose of +producing this effect. + +At the time the instruments were first exhibited in public the results +obtained with permanent magnets were not nearly so striking as when a +voltaic battery was employed, wherefore we thought it best to exhibit +only the latter form of instrument. + +The interest excited by the first published accounts of the operation of +the telephone led many persons to investigate the subject, and I doubt +not that numbers of experimenters have independently discovered that +permanent magnets might be employed instead of voltaic batteries. +Indeed, one gentleman, Professor Dolbear, of Tufts College, not only +claims to have discovered the magneto-electric telephone, but, I +understand, charges me with having obtained the idea from him through +the medium of a mutual friend. + +A still more powerful form of apparatus was constructed by using a +powerful compound horseshoe magnet in place of the straight rod which +had been previously used (see Fig. 11). Indeed, the sounds produced by +means of this instrument were of sufficient loudness to be faintly +audible to a large audience, and in this condition the instrument was +exhibited in the Essex Institute, in Salem, Massachusetts, on the 12th +of February, 1877, on which occasion a short speech shouted into a +similar telephone in Boston sixteen miles away, was heard by the +audience in Salem. The tones of the speaker's voice were distinctly +audible to an audience of six hundred people, but the articulation was +only distinct at a distance of about six feet. On the same occasion, +also, a report of the lecture was transmitted by word of mouth from +Salem to Boston, and published in the papers the next morning. + +From the form of telephone shown in Fig. 10 to the present form of the +instrument (Fig. 12) is but a step. It is, in fact, the arrangement of +Fig. 10 in a portable form, the magnet F. H. being placed inside the +handle and a more convenient form of mouthpiece provided.... + +It was always my belief that a certain ratio would be found between the +several parts of a telephone, and that the size of the instrument was +immaterial; but Professor Peirce was the first to demonstrate the +extreme smallness of the magnets which might be employed. And here, in +order to show the parallel lines in which we were working, I may mention +the fact that two or three days after I had constructed a telephone of +the portable form (Fig. 12), containing the magnet inside the handle, +Dr. Channing was kind enough to send me a pair of telephones of a +similar pattern, which had been invented by experimenters at Providence. +The convenient form of the mouthpiece shown in Fig. 12, now adopted by +me, was invented solely by my friend, Professor Peirce. I must also +express my obligations to my friend and associate, Mr. Thomas A. Watson, +of Salem, Massachusetts, who has for two years past given me his +personal assistance in carrying on my researches. + +In pursuing my investigations I have ever had one end in view--the +practical improvement of electric telegraphy--but I have come across +many facts which, while having no direct bearing upon the subject of +telegraphy, may yet possess an interest for you. + +For instance, I have found that a musical tone proceeds from a piece of +plumbago or retort carbon when an intermittent current of electricity is +passed through it, and I have observed the most curious audible effects +produced by the passage of reversed intermittent currents through the +human body. A breaker was placed in circuit with the primary wires of an +induction coil, and the fine wires were connected with two strips of +brass. One of these strips was held closely against the ear, and a loud +sound proceeded from it whenever the other slip was touched with the +other hand. The strips of brass were next held one in each hand. The +induced currents occasioned a muscular tremor in the fingers. Upon +placing my forefinger to my ear a loud crackling noise was audible, +seemingly proceeding from the finger itself. A friend who was present +placed my finger to his ear, but heard nothing. I requested him to hold +the strips himself. He was then distinctly conscious of a noise (which I +was unable to perceive) proceeding from his finger. In this case a +portion of the induced current passed through the head of the observer +when he placed his ear against his own finger, and it is possible that +the sound was occasioned by a vibration of the surfaces of the ear and +finger in contact. + +When two persons receive a shock from a Ruhmkorff's coil by clasping +hands, each taking hold of one wire of the coil with the free hand, a +sound proceeds from the clasped hands. The effect is not produced when +the hands are moist. When either of the two touches the body of the +other a loud sound comes from the parts in contact. When the arm of one +is placed against the arm of the other, the noise produced can be heard +at a distance of several feet. In all these cases a slight shock is +experienced so long as the contact is preserved. The introduction of a +piece of paper between the parts in contact does not materially +interfere with the production of the sounds, but the unpleasant effects +of the shock are avoided. + +[Illustration: Fig. 12] + +When an intermittent current from a Ruhmkorff's coil is passed through +the arms a musical note can be perceived when the ear is closely applied +to the arm of the person experimented upon. The sound seems to proceed +from the muscles of the fore-arm and from the biceps muscle. Mr. Elisha +Gray has also produced audible effects by the passage of electricity +through the human body. + +An extremely loud musical note is occasioned by the spark of a +Ruhmkorff's coil when the primary circuit is made and broken with +sufficient rapidity. When two breakers of different pitch are caused +simultaneously to open and close the primary circuit a double tone +proceeds from the spark. + +A curious discovery, which may be of interest to you, has been made by +Professor Blake. He constructed a telephone in which a rod of soft iron, +about six feet in length, was used instead of a permanent magnet. A +friend sang a continuous musical tone into the mouthpiece of a +telephone, like that shown in Fig. 12, which was connected with the soft +iron instrument alluded to above. It was found that the loudness of the +sound produced in this telephone varied with the direction in which the +iron rod was held, and that the maximum effect was produced when the rod +was in the position of the dipping needle. This curious discovery of +Professor Blake has been verified by myself. + +When a telephone is placed in circuit with a telegraph line the +telephone is found seemingly to emit sounds on its own account. The most +extraordinary noises are often produced, the causes of which are at +present very obscure. One class of sounds is produced by the inductive +influence of neighbouring wires and by leakage from them, the signals of +the Morse alphabet passing over neighbouring wires being audible in the +telephone, and another class can be traced to earth currents upon the +wire, a curious modification of this sound revealing the presence of +defective joints in the wire. + +Professor Blake informs me that he has been able to use the railroad +track for conversational purposes in place of a telegraph wire, and he +further states that when only one telephone was connected with the track +the sounds of Morse operating were distinctly audible in the telephone, +although the nearest telegraph wires were at least fifty feet distant. + +Professor Peirce has observed the most singular sounds produced from a +telephone in connection with a telegraph wire during the aurora +borealis, and I have just heard of a curious phenomenon lately observed +by Dr. Channing. In the city of Providence, Rhode Island, there is an +over-house wire about one mile in extent with a telephone at either end. +On one occasion the sound of music and singing was faintly audible in +one of the telephones. It seemed as if some one were practising vocal +music with a pianoforte accompaniment. The natural supposition was that +experiments were being made with the telephone at the other end of the +circuit, but upon inquiry this proved not to have been the case. +Attention having thus been directed to the phenomenon, a watch was kept +upon the instruments, and upon a subsequent occasion the same fact was +observed at both ends of the line by Dr. Channing and his friends. It +was proved that the sounds continued for about two hours, and usually +commenced about the same time. A searching examination of the line +disclosed nothing abnormal in its condition, and I am unable to give you +any explanation of this curious phenomenon. Dr. Channing has, however, +addressed a letter upon the subject to the editor of one of the +Providence papers, giving the names of such songs as were recognized, +and full details of the observations, in the hope that publicity may +lead to the discovery of the performer, and thus afford a solution of +the mystery. + +My friend, Mr. Frederick A. Gower, communicated to me a curious +observation made by him regarding the slight earth connection required +to establish a circuit for the telephone, and together we carried on a +series of experiments with rather startling results. We took a couple of +telephones and an insulated wire about 100 yards in length into a +garden, and were enabled to carry on conversation with the greatest ease +when we held in our hands what should have been the earth wire, so that +the connection with the ground was formed at either end through our +bodies, our feet being clothed with cotton socks and leather boots. The +day was fine, and the grass upon which we stood was seemingly perfectly +dry. Upon standing upon a gravel walk the vocal sounds, though much +diminished, were still perfectly intelligible, and the same result +occurred when standing upon a brick wall one foot in height, but no +sound was audible when one of us stood upon a block of freestone. + +One experiment which we made is so very interesting that I must speak of +it in detail. Mr. Gower made earth connection at his end of the line by +standing upon a grass plot, whilst at the other end of the line I stood +upon a wooden board. I requested Mr. Gower to sing a continuous musical +note, and to my surprise the sound was very distinctly audible from the +telephone in my hand. Upon examining my feet I discovered that a single +blade of grass was bent over the edge of the board, and that my foot +touched it. The removal of this blade of grass was followed by the +cessation of the sound from the telephone, and I found that the moment I +touched with the toe of my boot a blade of grass or the petal of a daisy +the sound was again audible. + +The question will naturally arise, Through what length of wire can the +telephone be used? In reply to this I may say that the maximum amount of +resistance through which the undulatory current will pass, and yet +retain sufficient force to produce an audible sound at the distant end, +has yet to be determined; no difficulty has, however, been experienced +in laboratory experiments in conversing through a resistance of 60,000 +ohms, which has been the maximum at my disposal. On one occasion, not +having a rheostat [for producing resistance] at hand, I passed the +current through the bodies of sixteen persons, who stood hand in hand. +The longest length of real telegraph line through which I have attempted +to converse has been about 250 miles. On this occasion no difficulty was +experienced so long as parallel lines were not in operation. Sunday was +chosen as the day on which it was probable other circuits would be at +rest. Conversation was carried on between myself, in New York, and Mr. +Thomas A. Watson, in Boston, until the opening of business upon the +other wires. When this happened the vocal sounds were very much +diminished, but still audible. It seemed, indeed, like talking through a +storm. Conversation, though possible, could be carried on with +difficulty, owing to the distracting nature of the interfering currents. + +I am informed by my friend Mr. Preece that conversation has been +successfully carried on through a submarine cable, sixty miles in +length, extending from Dartmouth to the Island of Guernsey, by means of +hand telephones. + + + + +PHOTOGRAPHING THE UNSEEN: THE ROENTGEN RAY + +H. J. W. DAM + + [By permission from _McClure's Magazine_, April, 1896, copyright by + S. S. McClure, Limited.] + + +In all the history of scientific discovery there has never been, +perhaps, so general, rapid, and dramatic an effect wrought on the +scientific centres of Europe as has followed, in the past four weeks, +upon an announcement made to the Würzburg Physico-Medical Society, at +their December [1895] meeting, by Professor William Konrad Röntgen, +professor of physics at the Royal University of Würzburg. The first news +which reached London was by telegraph from Vienna to the effect that a +Professor Röntgen, until then the possessor of only a local fame in the +town mentioned, had discovered a new kind of light, which penetrated and +photographed through everything. This news was received with a mild +interest, some amusement, and much incredulity; and a week passed. Then, +by mail and telegraph, came daily clear indications of the stir which +the discovery was making in all the great line of universities between +Vienna and Berlin. Then Röntgen's own report arrived, so cool, so +business-like, and so truly scientific in character, that it left no +doubt either of the truth or of the great importance of the preceding +reports. To-day, four weeks after the announcement, Röntgen's name is +apparently in every scientific publication issued this week in Europe; +and accounts of his experiments, of the experiments of others following +his method, and of theories as to the strange new force which he has +been the first to observe, fill pages of every scientific journal that +comes to hand. And before the necessary time elapses for this article to +attain publication in America, it is in all ways probable that the +laboratories and lecture-rooms of the United States will also be giving +full evidence of this contagious arousal of interest over a discovery so +strange that its importance cannot yet be measured, its utility be even +prophesied, or its ultimate effect upon long established scientific +beliefs be even vaguely foretold. + +The Röntgen rays are certain invisible rays resembling, in many +respects, rays of light, which are set free when a high-pressure +electric current is discharged through a vacuum tube. A vacuum tube is a +glass tube from which all the air, down to one-millionth of an +atmosphere, has been exhausted after the insertion of a platinum wire in +either end of the tube for connection with the two poles of a battery or +induction coil. When the discharge is sent through the tube, there +proceeds from the anode--that is, the wire which is connected with the +positive pole of the battery--certain bands of light, varying in colour +with the colour of the glass. But these are insignificant in comparison +with the brilliant glow which shoots from the cathode, or negative wire. +This glow excites brilliant phosphorescence in glass and many +substances, and these "cathode rays," as they are called, were observed +and studied by Hertz; and more deeply by his assistant, Professor +Lenard, Lenard having, in 1894, reported that the cathode rays would +penetrate thin films of aluminum, wood, and other substances, and +produce photographic results beyond. It was left, however, for Professor +Röntgen to discover that during the discharge quite other rays are set +free, which differ greatly from those described by Lenard as cathode +rays. The most marked difference between the two is the fact that +Röntgen rays are not deflected by a magnet, indicating a very essential +difference, while their range and penetrative power are incomparably +greater. In fact, all those qualities which have lent a sensational +character to the discovery of Röntgen's rays were mainly absent from +those of Lenard, to the end that, although Röntgen has not been working +in an entirely new field, he has by common accord been freely granted +all the honors of a great discovery. + +Exactly what kind of a force Professor Röntgen has discovered he does +not know. As will be seen below, he declines to call it a new kind of +light, or a new form of electricity. He has given it the name of the X +rays. Others speak of it as the Röntgen rays. Thus far its results only, +and not its essence, are known. In the terminology of science it is +generally called "a new mode of motion," or, in other words, a new +force. As to whether it is or not actually a force new to science, or +one of the known forces masquerading under strange conditions, weighty +authorities are already arguing. More than one eminent scientist has +already affected to see in it a key to the great mystery of the law of +gravity. All who have expressed themselves in print have admitted, with +more or less frankness, that, in view of Röntgen's discovery, science +must forthwith revise, possibly to a revolutionary degree, the long +accepted theories concerning the phenomena of light and sound. That the +X rays, in their mode of action, combine a strange resemblance to both +sound and light vibrations, and are destined to materially affect, if +they do not greatly alter, our views of both phenomena, is already +certain; and beyond this is the opening into a new and unknown field of +physical knowledge, concerning which speculation is already eager, and +experimental investigation already in hand, in London, Paris, Berlin, +and, perhaps, to a greater or less extent, in every well-equipped +physical laboratory in Europe. + +This is the present scientific aspect of the discovery. But, unlike most +epoch-making results from laboratories, this discovery is one which, to +a very unusual degree, is within the grasp of the popular and +non-technical imagination. Among the other kinds of matter which these +rays penetrate with ease is human flesh. That a new photography has +suddenly arisen which can photograph the bones, and, before long, the +organs of the human body; that a light has been found which can +penetrate, so as to make a photographic record, through everything from +a purse or a pocket to the walls of a room or a house, is news which +cannot fail to startle everybody. That the eye of the physician or +surgeon, long baffled by the skin, and vainly seeking to penetrate the +unfortunate darkness of the human body, is now to be supplemented by a +camera, making all the parts of the human body as visible, in a way, as +the exterior, appears certainly to be a greater blessing to humanity +than even the Listerian antiseptic system of surgery; and its benefits +must inevitably be greater than those conferred by Lister, great as the +latter have been. Already, in the few weeks since Röntgen's +announcement, the results of surgical operations under the new system +are growing voluminous. In Berlin, not only new bone fractures are being +immediately photographed, but joined fractures, as well, in order to +examine the results of recent surgical work. In Vienna, imbedded bullets +are being photographed, instead of being probed for, and extracted with +comparative ease. In London, a wounded sailor, completely paralyzed, +whose injury was a mystery, has been saved by the photographing of an +object imbedded in the spine, which, upon extraction, proved to be a +small knife-blade. Operations for malformations, hitherto obscure, but +now clearly revealed by the new photography, are already becoming +common, and are being reported from all directions. Professor Czermark +of Graz has photographed the living skull, denuded of flesh and hair, +and has begun the adaptation of the new photography to brain study. The +relation of the new rays to thought rays is being eagerly discussed in +what may be called the non-exact circles and journals; and all that +numerous group of inquirers into the occult, the believers in +clairvoyance, spiritualism, telepathy, and kindred orders of alleged +phenomena, are confident of finding in the new force long-sought facts +in proof of their claims. Professor Neusser in Vienna has photographed +gallstones in the liver of one patient (the stone showing snow-white in +the negative), and a stone in the bladder of another patient. His +results so far induce him to announce that all the organs of the human +body can, and will, shortly, be photographed. Lannelongue of Paris has +exhibited to the Academy of Science photographs of bones showing +inherited tuberculosis which had not otherwise revealed itself. Berlin +has already formed a society of forty for the immediate prosecution of +researches into both the character of the new force and its +physiological possibilities. In the next few weeks these strange +announcements will be trebled or quadrupled, giving the best evidence +from all quarters of the great future that awaits the Röntgen rays, and +the startling impetus to the universal search for knowledge that has +come at the close of the nineteenth century from the modest little +laboratory in the Pleicher Ring at Würzburg. + +The Physical Institute, Professor Röntgen's particular domain, is a +modest building of two stories and basement, the upper story +constituting his private residence, and the remainder of the building +being given over to lecture rooms, laboratories, and their attendant +offices. At the door I was met by an old serving-man of the idolatrous +order, whose pain was apparent when I asked for "Professor" Röntgen, and +he gently corrected me with "Herr Doctor Röntgen." As it was evident, +however, that we referred to the same person, he conducted me along a +wide, bare hall, running the length of the building, with blackboards +and charts on the walls. At the end he showed me into a small room on +the right. This contained a large table desk, and a small table by the +window, covered by photographs, while the walls held rows of shelves +laden with laboratory and other records. An open door led into a +somewhat larger room, perhaps twenty feet by fifteen, and I found myself +gazing into a laboratory which was the scene of the discovery--a +laboratory which, though in all ways modest, is destined to be +enduringly historical. + +There was a wide table shelf running along the farther side, in front of +the two windows, which were high, and gave plenty of light. In the +centre was a stove; on the left, a small cabinet whose shelves held the +small objects which the professor had been using. There was a table in +the left-hand corner; and another small table--the one on which living +bones were first photographed--was near the stove, and a Ruhmkorff coil +was on the right. The lesson of the laboratory was eloquent. Compared, +for instance, with the elaborate, expensive, and complete apparatus of, +say, the University of London, or of any of the great American +universities, it was bare and unassuming to a degree. It mutely said +that in the great march of science it is the genius of man, and not the +perfection of appliances, that breaks new ground in the great territory +of the unknown. It also caused one to wonder at and endeavour to imagine +the great things which are to be done through elaborate appliances with +the Röntgen rays--a field in which the United States, with its foremost +genius in invention, will very possibly, if not probably, take the +lead--when the discoverer himself had done so much with so little. +Already, in a few weeks, a skilled London operator, Mr. A. A. C. +Swinton, has reduced the necessary time of exposure for Röntgen +photographs from fifteen minutes to four. He used, however, a Tesla oil +coil, discharged by twelve half-gallon Leyden jars, with an alternating +current of twenty thousand volts' pressure. Here were no oil coils, +Leyden jars, or specially elaborate and expensive machines. There were +only a Ruhmkorff coil and Crookes (vacuum) tube and the man himself. + +Professor Röntgen entered hurriedly, something like an amiable gust of +wind. He is a tall, slender, and loose-limbed man, whose whole +appearance bespeaks enthusiasm and energy. He wore a dark blue sack +suit, and his long, dark hair stood straight up from his forehead, as if +he were permanently electrified by his own enthusiasm. His voice is full +and deep, he speaks rapidly, and, altogether, he seems clearly a man +who, once upon the track of a mystery which appealed to him, would +pursue it with unremitting vigor. His eyes are kind, quick, and +penetrating; and there is no doubt that he much prefers gazing at a +Crookes tube to beholding a visitor, visitors at present robbing him of +much valued time. The meeting was by appointment, however, and his +greeting was cordial and hearty. In addition to his own language he +speaks French well and English scientifically, which is different from +speaking it popularly. These three tongues being more or less within the +equipment of his visitor, the conversation proceeded on an international +or polyglot basis, so to speak, varying at necessity's demand. + +It transpired in the course of inquiry, that the professor is a married +man and fifty years of age, though his eyes have the enthusiasm of +twenty-five. He was born near Zurich, and educated there, and completed +his studies and took his degree at Utrecht. He has been at Würzburg +about seven years, and had made no discoveries which he considered of +great importance prior to the one under consideration. These details +were given under good-natured protest, he failing to understand why his +personality should interest the public. He declined to admire himself or +his results in any degree, and laughed at the idea of being famous. The +professor is too deeply interested in science to waste any time in +thinking about himself. His emperor had feasted, flattered, and +decorated him, and he was loyally grateful. It was evident, however, +that fame and applause had small attractions for him, compared to the +mysteries still hidden in the vacuum tubes of the other room. + +"Now, then," said he, smiling, and with some impatience, when the +preliminary questions at which he chafed were over, "you have come to +see the invisible rays." + +"Is the invisible visible?" + +"Not to the eye; but its results are. Come in here." + +[Illustration: BONES OF A HUMAN FOOT PHOTOGRAPHED THROUGH THE FLESH + +From a photograph by A. A. C. Swinton, Victoria Street, London. +Exposure, fifty-five seconds] + +He led the way to the other square room mentioned, and indicated the +induction coil with which his researches were made, an ordinary +Ruhmkorff coil, with a spark of from four to six inches, charged by a +current of twenty amperes. Two wires led from the coil, through an open +door, into a smaller room on the right. In this room was a small table +carrying a Crookes tube connected with the coil. The most striking +object in the room, however, was a huge and mysterious tin box about +seven feet high and four feet square. It stood on end, like a huge +packing case, its side being perhaps five inches from the Crookes tube. + +The professor explained the mystery of the tin box, to the effect that +it was a device of his own for obtaining a portable dark-room. When he +began his investigations he used the whole room, as was shown by the +heavy blinds and curtains so arranged as to exclude the entrance of all +interfering light from the windows. In the side of the tin box, at the +point immediately against the tube, was a circular sheet of aluminum one +millimetre in thickness, and perhaps eighteen inches in diameter, +soldered to the surrounding tin. To study his rays the professor had +only to turn on the current, enter the box, close the door, and in +perfect darkness inspect only such light or light effects as he had a +right to consider his own, hiding his light, in fact, not under the +Biblical bushel, but in a more commodious box. + +"Step inside," said he, opening the door, which was on the side of the +box farthest from the tube. I immediately did so, not altogether certain +whether my skeleton was to be photographed for general inspection, or my +secret thoughts held up to light on a glass plate. "You will find a +sheet of barium paper on the shelf," he added, and then went away to the +coil. The door was closed, and the interior of the box became black +darkness. The first thing I found was a wooden stool, on which I +resolved to sit. Then I found the shelf on the side next the tube, and +then the sheet of paper prepared with barium platinocyanide. I was thus +being shown the first phenomenon which attracted the discoverer's +attention and led to his discovery, namely, the passage of rays, +themselves wholly invisible, whose presence was only indicated by the +effect they produced on a piece of sensitized photographic paper. + +A moment later, the black darkness was penetrated by the rapid snapping +sound of the high-pressure current in action, and I knew that the tube +outside was glowing. I held the sheet vertically on the shelf, perhaps +four inches from the plate. There was no change, however, and nothing +was visible. + +"Do you see anything?" he called. + +"No." + +"The tension is not high enough;" and he proceeded to increase the +pressure by operating an apparatus of mercury in long vertical tubes +acted upon automatically by a weight lever which stood near the coil. In +a few moments the sound of the discharge again began, and then I made my +first acquaintance with the Röntgen rays. + +The moment the current passed, the paper began to glow. A yellowish +green light spread all over its surface in clouds, waves and flashes. +The yellow-green luminescence, all the stranger and stronger in the +darkness, trembled, wavered, and floated over the paper, in rhythm with +the snapping of the discharge. Through the metal plate, the paper, +myself, and the tin box, the invisible rays were flying, with an effect +strange, interesting and uncanny. The metal plate seemed to offer no +appreciable resistance to the flying force, and the light was as rich +and full as if nothing lay between the paper and the tube. + +"Put the book up," said the professor. + +I felt upon the shelf, in the darkness, a heavy book, two inches in +thickness, and placed this against the plate. It made no difference. The +rays flew through the metal and the book as if neither had been there, +and the waves of light, rolling cloud-like over the paper, showed no +change in brightness. It was a clear, material illustration of the ease +with which paper and wood are penetrated. And then I laid book and paper +down, and put my eyes against the rays. All was blackness, and I neither +saw nor felt anything. The discharge was in full force, and the rays +were flying through my head, and, for all I knew, through the side of +the box behind me. But they were invisible and impalpable. They gave no +sensation whatever. Whatever the mysterious rays may be, they are not to +be seen, and are to be judged only by their works. + +I was loath to leave this historical tin box, but time pressed. I +thanked the professor, who was happy in the reality of his discovery and +the music of his sparks. Then I said: "Where did you first photograph +living bones?" + +"Here," he said, leading the way into the room where the coil stood. He +pointed to a table on which was another--the latter a small +short-legged wooden one with more the shape and size of a wooden seat. +It was two feet square and painted coal black. I viewed it with +interest. I would have bought it, for the little table on which light +was first sent through the human body will some day be a great +historical curiosity; but it was not for sale. A photograph of it would +have been a consolation, but for several reasons one was not to be had +at present. However, the historical table was there, and was duly +inspected. + +"How did you take the first hand photograph?" I asked. + +The professor went over to a shelf by the window, where lay a number of +prepared glass plates, closely wrapped in black paper. He put a Crookes +tube underneath the table, a few inches from the under side of its top. +Then he laid his hand flat on the top of the table, and placed the glass +plate loosely on his hand. + +"You ought to have your portrait painted in that attitude," I suggested. + +"No, that is nonsense," said he, smiling. + +"Or be photographed." This suggestion was made with a deeply hidden +purpose. + +The rays from the Röntgen eyes instantly penetrated the deeply hidden +purpose. "Oh, no," said he; "I can't let you make pictures of me. I am +too busy." Clearly the professor was entirely too modest to gratify the +wishes of the curious world. + +"Now, Professor," said I, "will you tell me the history of the +discovery?" + +"There is no history," he said. "I have been for a long time interested +in the problem of the cathode rays from a vacuum tube as studied by +Hertz and Lenard. I had followed their and other researches with great +interest, and determined, as soon as I had the time, to make some +researches of my own. This time I found at the close of last October. I +had been at work for some days when I discovered something new." + +"What was the date?" + +"The eighth of November." + +"And what was the discovery?" + +"I was working with a Crookes tube covered by a shield of black +cardboard. A piece of barium platinocyanide paper lay on the bench +there. I had been passing a current through the tube, and I noticed a +peculiar black line across the paper." + +"What of that?" + +"The effect was one which could only be produced, in ordinary parlance, +by the passage of light. No light could come from the tube, because the +shield which covered it was impervious to any light known, even that of +the electric arc." + +"And what did you think?" + +"I did not think; I investigated. I assumed that the effect must have +come from the tube, since its character indicated that it could come +from nowhere else. I tested it. In a few minutes there was no doubt +about it. Rays were coming from the tube which had a luminescent effect +upon the paper. I tried it successfully at greater and greater +distances, even at two metres. It seemed at first a new kind of +invisible light. It was clearly something new, something unrecorded." + +"Is it light?" + +"No." + +"Is it electricity?" + +"Not in any known form." + +"What is it?" + +"I don't know." + +And the discoverer of the X rays thus stated as calmly his ignorance of +their essence as has everybody else who has written on the phenomena +thus far. + +"Having discovered the existence of a new kind of rays, I of course +began to investigate what they would do." He took up a series of +cabinet-sized photographs. "It soon appeared from tests that the rays +had penetrative powers to a degree hitherto unknown. They penetrated +paper, wood, and cloth with ease; and the thickness of the substance +made no perceptible difference, within reasonable limits." He showed +photographs of a box of laboratory weights of platinum, aluminum, and +brass, they and the brass hinges all having been photographed from a +closed box, without any indication of the box. Also a photograph of a +coil of fine wire, wound on a wooden spool, the wire having been +photographed, and the wood omitted. "The rays," he continued, "passed +through all the metals tested, with a facility varying, roughly +speaking, with the density of the metal. These phenomena I have +discussed carefully in my report to the Würzburg society, and you will +find all the technical results therein stated." He showed a photograph +of a small sheet of zinc. This was composed of smaller plates soldered +laterally with solders of different metallic proportions. The differing +lines of shadow, caused by the difference in the solders, were visible +evidence that a new means of detecting flaws and chemical variations in +metals had been found. A photograph of a compass showed the needle and +dial taken through the closed brass cover. The markings of the dial were +in red metallic paint, and thus interfered with the rays, and were +reproduced. "Since the rays had this great penetrative power, it seemed +natural that they should penetrate flesh, and so it proved in +photographing the hand, as I showed you." + +A detailed discussion of the characteristics of his rays the professor +considered unprofitable and unnecessary. He believes, though, that these +mysterious radiations are not light, because their behaviour is +essentially different from that of light rays, even those light rays +which are themselves invisible. The Röntgen rays cannot be reflected by +reflecting surfaces, concentrated by lenses, or refracted or diffracted. +They produce photographic action on a sensitive film, but their action +is weak as yet, and herein lies the first important field of their +development. The professor's exposures were comparatively long--an +average of fifteen minutes in easily penetrable media, and half an hour +or more in photographing the bones of the hand. Concerning vacuum tubes, +he said that he preferred the Hittorf, because it had the most perfect +vacuum, the highest degree of air exhaustion being the consummation most +desirable. In answer to a question, "What of the future?" he said: + +"I am not a prophet, and I am opposed to prophesying. I am pursuing my +investigations, and as fast as my results are verified I shall make them +public." + +"Do you think the rays can be so modified as to photograph the organs of +the human body?" + +In answer he took up the photograph of the box of weights. "Here are +already modifications," he said, indicating the various degrees of +shadow produced by the aluminum, platinum, and brass weights, the brass +hinges, and even the metallic stamped lettering on the cover of the box, +which was faintly perceptible. + +"But Professor Neusser has already announced that the photographing of +the various organs is possible." + +"We shall see what we shall see," he said. "We have the start now; the +development will follow in time." + +"You know the apparatus for introducing the electric light into the +stomach?" + +"Yes." + +"Do you think that this electric light will become a vacuum tube for +photographing, from the stomach, any part of the abdomen or thorax?" + +The idea of swallowing a Crookes tube, and sending a high frequency +current down into one's stomach, seemed to him exceedingly funny. "When +I have done it, I will tell you," he said, smiling, resolute in abiding +by results. + +"There is much to do, and I am busy, very busy," he said in conclusion. +He extended his hand in farewell, his eyes already wandering toward his +work in the inside room. And his visitor promptly left him; the words, +"I am busy," said in all sincerity, seeming to describe in a single +phrase the essence of his character and the watchword of a very unusual +man. + +Returning by way of Berlin, I called upon Herr Spies of the Urania, +whose photographs after the Röntgen method were the first made public, +and have been the best seen thus far. In speaking of the discovery he +said: + +"I applied it, as soon as the penetration of flesh was apparent, to the +photograph of a man's hand. Something in it had pained him for years, +and the photograph at once exhibited a small foreign object, as you can +see;" and he exhibited a copy of the photograph in question. "The speck +there is a small piece of glass, which was immediately extracted, and +which, in all probability, would have otherwise remained in the man's +hand to the end of his days." All of which indicates that the needle +which has pursued its travels in so many persons, through so many years, +will be suppressed by the camera. + +"My next object is to photograph the bones of the entire leg," continued +Herr Spies. "I anticipate no difficulty, though it requires some thought +in manipulation." + +It will be seen that the Röntgen rays and their marvellous practical +possibilities are still in their infancy. The first successful +modification of the action of the rays so that the varying densities of +bodily organs will enable them to be photographed will bring all such +morbid growths as tumours and cancers into the photographic field, to +say nothing of vital organs which may be abnormally developed or +degenerate. How much this means to medical and surgical practice it +requires little imagination to conceive. Diagnosis, long a painfully +uncertain science, has received an unexpected and wonderful assistant; +and how greatly the world will benefit thereby, how much pain will be +saved, only the future can determine. In science a new door has been +opened where none was known to exist, and a side-light on phenomena has +appeared, of which the results may prove as penetrating and astonishing +as the Röntgen rays themselves. The most agreeable feature of the +discovery is the opportunity it gives for other hands to help; and the +work of these hands will add many new words to the dictionaries, many +new facts to science, and, in the years long ahead of us, fill many more +volumes than there are paragraphs in this brief and imperfect account. + + + + +THE WIRELESS TELEGRAPH + +GEORGE ILES + + [From "Flame, Electricity and the Camera," copyright by Doubleday, + Page & Co., New York.] + + +In a series of experiments interesting enough but barren of utility, the +water of a canal, river, or bay has often served as a conductor for the +telegraph. Among the electricians who have thus impressed water into +their service was Professor Morse. In 1842 he sent a few signals across +the channel from Castle Garden, New York, to Governor's Island, a +distance of a mile. With much better results, he sent messages, later in +the same year, from one side of the canal at Washington to the other, a +distance of eighty feet, employing large copper plates at each terminal. +The enormous current required to overcome the resistance of water has +barred this method from practical adoption. + +We pass, therefore, to electrical communication as effected by +induction--the influence which one conductor exerts on another through +an intervening insulator. At the outset we shall do well to bear in mind +that magnetic phenomena, which are so closely akin to electrical, are +always inductive. To observe a common example of magnetic induction, we +have only to move a horseshoe magnet in the vicinity of a compass +needle, which will instantly sway about as if blown hither and thither +by a sharp draught of air. This action takes place if a slate, a pane of +glass, or a shingle is interposed between the needle and its perturber. +There is no known insulator for magnetism, and an induction of this kind +exerts itself perceptibly for many yards when large masses of iron are +polarised, so that the derangement of compasses at sea from moving iron +objects aboard ship, or from ferric ores underlying a sea-coast, is a +constant peril to the mariner. + +Electrical conductors behave much like magnetic masses. A current +conveyed by a conductor induces a counter-current in all surrounding +bodies, and in a degree proportioned to their conductive power. This +effect is, of course, greatest upon the bodies nearest at hand, and we +have already remarked its serious retarding effect in ocean telegraphy. +When the original current is of high intensity, it can induce a +perceptible current in another wire at a distance of several miles. In +1842 Henry remarked that electric waves had this quality, but in that +early day of electrical interpretation the full significance of the fact +eluded him. In the top room of his house he produced a spark an inch +long, which induced currents in wires stretched in his cellar, through +two thick floors and two rooms which came between. Induction of this +sort causes the annoyance, familiar in single telephonic circuits, of +being obliged to overhear other subscribers, whose wires are often far +away from our own. + +The first practical use of induced currents in telegraphy was when Mr. +Edison, in 1885, enabled the trains on a line of the Staten Island +Railroad to be kept in constant communication with a telegraphic wire, +suspended in the ordinary way beside the track. The roof of a car was of +insulated metal, and every tap of an operator's key within the walls +electrified the roof just long enough to induce a brief pulse through +the telegraphic circuit. In sending a message to the car this wire was, +moment by moment, electrified, inducing a response first in the car +roof, and next in the "sounder" beneath it. This remarkable apparatus, +afterward used on the Lehigh Valley Railroad, was discontinued from lack +of commercial support, although it would seem to be advantageous to +maintain such a service on other than commercial grounds. In case of +chance obstructions on the track, or other peril, to be able to +communicate at any moment with a train as it speeds along might mean +safety instead of disaster. The chief item in the cost of this system is +the large outlay for a special telegraphic wire. + +The next electrician to employ induced currents in telegraphy was Mr. +(now Sir) William H. Preece, the engineer then at the head of the +British telegraph system. Let one example of his work be cited. In 1896 +a cable was laid between Lavernock, near Cardiff, on the Bristol +Channel, and Flat Holme, an island three and a third miles off. As the +channel at this point is a much-frequented route and anchor ground, the +cable was broken again and again. As a substitute for it Mr. Preece, in +1898, strung wires along the opposite shores, and found that an electric +pulse sent through one wire instantly made itself heard in a telephone +connected with the other. It would seem that in this etheric form of +telegraphy the two opposite lines of wire must be each as long as the +distance which separates them; therefore, to communicate across the +English Channel from Dover to Calais would require a line along each +coast at least twenty miles in length. Where such lines exist for +ordinary telegraphy, they might easily lend themselves to the Preece +system of signalling in case a submarine cable were to part. + +Marconi, adopting electrostatic instead of electro-magnetic waves, has +won striking results. Let us note the chief of his forerunners, as they +prepared the way for him. In 1864 Maxwell observed that electricity and +light have the same velocity, 186,400 miles a second, and he formulated +the theory that electricity propagates itself in waves which differ from +those of light only in being longer. This was proved to be true by +Hertz, who in 1888 showed that where alternating currents of very high +frequency were set up in an open circuit, the energy might be conveyed +entirely away from the circuit into the surrounding space as electric +waves. His detector was a nearly closed circle of wire, the ends being +soldered to metal balls almost in contact. With this simple apparatus he +demonstrated that electric waves move with the speed of light, and that +they can be reflected and refracted precisely as if they formed a +visible beam. At a certain intensity of strain the air insulation broke +down, and the air became a conductor. This phenomenon of passing quite +suddenly from a non-conductive to a conductive state is, as we shall +duly see, also to be noted when air or other gases are exposed to the X +ray. + +Now for the effect of electric waves such as Hertz produced, when they +impinge upon substances reduced to powder or filings. Conductors, such +as the metals, are of inestimable service to the electrician; of equal +value are non-conductors, such as glass and gutta-percha, as they +strictly fence in an electric stream. A third and remarkable vista opens +to experiment when it deals with substances which, in their normal +state, are non-conductive, but which, agitated by an electric wave, +instantly become conductive in a high degree. As long ago as 1866 Mr. S. +A. Varley noticed that black lead, reduced to a loose dust, effectually +intercepted a current from fifty Daniell cells, although the battery +poles were very near each other. When he increased the electric tension +four- to six-fold, the black-lead particles at once compacted themselves +so as to form a bridge of excellent conductivity. On this principle he +invented a lightning-protector for electrical instruments, the incoming +flash causing a tiny heap of carbon dust to provide it with a path +through which it could safely pass to the earth. Professor Temistocle +Calzecchi Onesti of Fermo, in 1885, in an independent series of +researches, discovered that a mass of powdered copper is a non-conductor +until an electric wave beats upon it; then, in an instant, the mass +resolves itself into a conductor almost as efficient as if it were a +stout, unbroken wire. Professor Edouard Branly of Paris, in 1891, on +this principle devised a coherer, which passed from resistance to +invitation when subjected to an electric impulse from afar. He enhanced +the value of his device by the vital discovery that the conductivity +bestowed upon filings by electric discharges could be destroyed by +simply shaking or tapping them apart. + +In a homely way the principle of the coherer is often illustrated in +ordinary telegraphic practice. An operator notices that his instrument +is not working well, and he suspects that at some point in his circuit +there is a defective contact. A little dirt, or oxide, or dampness, has +come in between two metallic surfaces; to be sure, they still touch each +other, but not in the firm and perfect way demanded for his work. +Accordingly he sends a powerful current abruptly into the line, which +clears its path thoroughly, brushes aside dirt, oxide, or moisture, and +the circuit once more is as it should be. In all likelihood, the coherer +is acted upon in the same way. Among the physicists who studied it in +its original form was Dr. Oliver J. Lodge. He improved it so much that, +in 1894, at the Royal Institution in London, he was able to show it as +an electric eye that registered the impact of invisible rays at a +distance of more than forty yards. He made bold to say that this +distance might be raised to half a mile. + +As early as 1879 Professor D. E. Hughes began a series of experiments in +wireless telegraphy, on much the lines which in other hands have now +reached commercial as well as scientific success. Professor Hughes was +the inventor of the microphone, and that instrument, he declared, +affords an unrivalled means of receiving wireless messages, since it +requires no tapping to restore its non-conductivity. In his researches +this investigator was convinced that his signals were propagated, not by +electro-magnetic induction, but by aerial electric waves spreading out +from an electric spark. Early in 1880 he showed his apparatus to +Professor Stokes, who observed its operation carefully. His dictum was +that he saw nothing which could not be explained by known +electro-magnetic effects. This erroneous judgment so discouraged +Professor Hughes that he desisted from following up his experiments, and +thus, in all probability, the birth of the wireless telegraph was for +several years delayed.[3] + +[Illustration: Fig. 71.--Marconi coherer, enlarged view] + +The coherer, as improved by Marconi, is a glass tube about one and +one-half inches long and about one-twelfth of an inch in internal +diameter. The electrodes are inserted in this tube so as almost to +touch; between them is about one-thirtieth of an inch filled with a +pinch of the responsive mixture which forms the pivot of the whole +contrivance. This mixture is 90 per cent. nickel filings, 10 per cent. +hard silver filings, and a mere trace of mercury; the tube is exhausted +of air to within one ten-thousandth part (Fig. 71). How does this trifle +of metallic dust manage loudly to utter its signals through a +telegraphic sounder, or forcibly indent them upon a moving strip of +paper? Not directly, but indirectly, as the very last refinement of +initiation. Let us imagine an ordinary telegraphic battery strong enough +loudly to tick out a message. Be it ever so strong it remains silent +until its circuit is completed, and for that completion the merest touch +suffices. Now the thread of dust in the coherer forms part of such a +telegraphic circuit: as loose dust it is an effectual bar and obstacle, +under the influence of electric waves from afar it changes instantly to +a coherent metallic link which at once completes the circuit and +delivers the message. + +An electric impulse, almost too attenuated for computation, is here able +to effect such a change in a pinch of dust that it becomes a free avenue +instead of a barricade. Through that avenue a powerful blow from a local +store of energy makes itself heard and felt. No device of the trigger +class is comparable with this in delicacy. An instant after a signal has +taken its way through the coherer a small hammer strikes the tiny tube, +jarring its particles asunder, so that they resume their normal state of +high resistance. We may well be astonished at the sensitiveness of the +metallic filings to an electric wave originating many miles away, but +let us remember how clearly the eye can see a bright lamp at the same +distance as it sheds a sister beam. Thus far no substance has been +discovered with a mechanical responsiveness to so feeble a ray of light; +in the world of nature and art the coherer stands alone. The electric +waves employed by Marconi are about four feet long, or have a frequency +of about 250,000,000 per second. Such undulations pass readily through +brick or stone walls, through common roofs and floors--indeed, through +all substances which are non-conductive to electric waves of ordinary +length. Were the energy of a Marconi sending-instrument applied to an +arc-lamp, it would generate a beam of a thousand candle-power. We have +thus a means of comparing the sensitiveness of the retina to light with +the responsiveness of the Marconi coherer to electric waves, after both +radiations have undergone a journey of miles. + +An essential feature of this method of etheric telegraphy, due to +Marconi himself, is the suspension of a perpendicular wire at each +terminus, its length twenty feet for stations a mile apart, forty feet +for four miles, and so on, the telegraphic distance increasing as the +square of the length of suspended wire. In the Kingstown regatta, July, +1898, Marconi sent from a yacht under full steam a report to the shore +without the loss of a moment from start to finish. This feat was +repeated during the protracted contest between the _Columbia_ and the +_Shamrock_ yachts in New York Bay, October, 1899. On March 28, 1899, +Marconi signals put Wimereux, two miles north of Boulogne, in +communication with the South Foreland Lighthouse, thirty-two miles +off.[4] In August, 1899, during the manoeuvres of the British navy, +similar messages were sent as far as eighty miles. It was clearly +demonstrated that a new power had been placed in the hands of a naval +commander. "A touch on a button in a flagship is all that is now needed +to initiate every tactical evolution in a fleet, and insure an almost +automatic precision in the resulting movements of the ships. The +flashing lantern is superseded at night, flags and the semaphore by day, +or, if these are retained, it is for services purely auxiliary. The +hideous and bewildering shrieks of the steam-siren need no longer be +heard in a fog, and the uncertain system of gun signals will soon become +a thing of the past." The interest of the naval and military strategist +in the Marconi apparatus extends far beyond its communication of +intelligence. Any electrical appliance whatever may be set in motion by +the same wave that actuates a telegraphic sounder. A fuse may be +ignited, or a motor started and directed, by apparatus connected with +the coherer, for all its minuteness. Mr. Walter Jamieson and Mr. John +Trotter have devised means for the direction of torpedoes by ether +waves, such as those set at work in the wireless telegraph. Two rods +projecting above the surface of the water receive the waves, and are in +circuit with a coherer and a relay. At the will of the distant operator +a hollow wire coil bearing a current draws in an iron core either to the +right or to the left, moving the helm accordingly. + +As the news of the success of the Marconi telegraph made its way to the +London Stock Exchange there was a fall in the shares of cable companies. +The fear of rivalry from the new invention was baseless. As but fifteen +words a minute are transmissible by the Marconi system, it evidently +does not compete with a cable, such as that between France and England, +which can transmit 2,500 words a minute without difficulty. The Marconi +telegraph comes less as a competitor to old systems than as a mode of +communication which creates a field of its own. We have seen what it may +accomplish in war, far outdoing any feat possible to other apparatus, +acoustic, luminous, or electrical. In quite as striking fashion does it +break new ground in the service of commerce and trade. It enables +lighthouses continually to spell their names, so that receivers aboard +ship may give the steersmen their bearings even in storm and fog. In the +crowded condition of the steamship "lanes" which cross the Atlantic, a +priceless security against collision is afforded the man at the helm. +On November 15, 1899, Marconi telegraphed from the American liner _St. +Paul_ to the Needles, sixty-six nautical miles away. On December 11 and +12, 1901, he received wireless signals near St. John's, Newfoundland, +sent from Poldhu, Cornwall, England, or a distance of 1,800 miles,--a +feat which astonished the world. In many cases the telegraphic business +to an island is too small to warrant the laying of a cable; hence we +find that Trinidad and Tobago are to be joined by the wireless system, +as also five islands of the Hawaiian group, eight to sixty-one miles +apart. + +A weak point in the first Marconi apparatus was that anybody within the +working radius of the sending-instrument could read its messages. To +modify this objection secret codes were at times employed, as in +commerce and diplomacy. A complete deliverance from this difficulty is +promised in attuning a transmitter and a receiver to the same note, so +that one receiver, and no other, shall respond to a particular frequency +of impulses. The experiments which indicate success in this vital +particular have been conducted by Professor Lodge. + +When electricians, twenty years ago, committed energy to a wire and thus +enabled it to go round a corner, they felt that they had done well. The +Hertz waves sent abroad by Marconi ask no wire, as they find their way, +not round a corner, but through a corner. On May 1, 1899, a party of +French officers on board the _Ibis_ at Sangatte, near Calais, spoke to +Wimereux by means of a Marconi apparatus, with Cape Grisnez, a lofty +promontory, intervening. In ascertaining how much the earth and the sea +may obstruct the waves of Hertz there is a broad and fruitful field for +investigation. "It may be," says Professor John Trowbridge, "that such +long electrical waves roll around the surface of such obstructions very +much as waves of sound and of water would do." + +[Illustration: Fig. 73--Discontinuous electric waves] + +[Illustration: Fig. 74--Wehnelt interrupter] + +It is singular how discoveries sometimes arrive abreast of each other so +as to render mutual aid, or supply a pressing want almost as soon as it +is felt. The coherer in its present form is actuated by waves of +comparatively low frequency, which rise from zero to full height in +extremely brief periods, and are separated by periods decidedly longer +(Fig. 73). What is needed is a plan by which the waves may flow either +continuously or so near together that they may lend themselves to +attuning. Dr. Wehnelt, by an extraordinary discovery, may, in all +likelihood, provide the lacking device in the form of his interrupter, +which breaks an electric circuit as often as two thousand times a +second. The means for this amazing performance are simplicity itself +(Fig. 74). A jar, _a_, containing a solution of sulphuric acid has two +electrodes immersed in it; one of them is a lead plate of large surface, +_b_; the other is a small platinum wire which protrudes from a glass +tube, _d_. A current passing through the cell between the two metals at +_c_ is interrupted, in ordinary cases five hundred times a second, and +in extreme cases four times as often, by bubbles of gas given off from +the wire instant by instant. + + +FOOTNOTES: + +[3] "History of the Wireless Telegraph," by J. J. Fahie. Edinburgh and +London, William Blackwood & Sons; New York, Dodd, Mead & Co., 1899. This +work is full of interesting detail, well illustrated. + +[4] The value of wireless telegraphy in relation to disasters at sea was +proved in a remarkable way yesterday morning. While the Channel was +enveloped in a dense fog, which had lasted throughout the greater part +of the night, the East Goodwin Lightship had a very narrow escape from +sinking at her moorings by being run into by the steamship _R. F. +Matthews_, 1,964 tons gross burden, of London, outward bound from the +Thames. The East Goodwin Lightship is one of four such vessels marking +the Goodwin Sands, and, curiously enough, it happens to be the one ship +which has been fitted out with Signor Marconi's installation for +wireless telegraphy. The vessel was moored about twelve miles to the +northeast of the South Foreland Lighthouse (where there is another +wireless-telegraphy installation), and she is about ten miles from the +shore, being directly opposite Deal. The information regarding the +collision was at once communicated by wireless telegraphy from the +disabled lightship to the South Foreland Lighthouse, where Mr. Bullock, +assistant to Signor Marconi, received the following message: "We have +just been run into by the steamer _R. F. Matthews_ of London. Steamship +is standing by us. Our bows very badly damaged." Mr. Bullock immediately +forwarded this information to the Trinity House authorities at +Ramsgate.--_Times_, April 29, 1899. + + + + +ELECTRICITY, WHAT ITS MASTERY MEANS: WITH A REVIEW AND A PROSPECT + +GEORGE ILES + + [From "Flame, Electricity and the Camera," copyright by Doubleday, + Page & Co., New York.] + + +With the mastery of electricity man enters upon his first real +sovereignty of nature. As we hear the whirr of the dynamo or listen at +the telephone, as we turn the button of an incandescent lamp or travel +in an electromobile, we are partakers in a revolution more swift and +profound than has ever before been enacted upon earth. Until the +nineteenth century fire was justly accounted the most useful and +versatile servant of man. To-day electricity is doing all that fire ever +did, and doing it better, while it accomplishes uncounted tasks far +beyond the reach of flame, however ingeniously applied. We may thus +observe under our eyes just such an impetus to human intelligence and +power as when fire was first subdued to the purposes of man, with the +immense advantage that, whereas the subjugation of fire demanded ages of +weary and uncertain experiment, the mastery of electricity is, for the +most part, the assured work of the nineteenth century, and, in truth, +very largely of its last three decades. The triumphs of the electrician +are of absorbing interest in themselves, they bear a higher significance +to the student of man as a creature who has gradually come to be what he +is. In tracing the new horizons won by electric science and art, a beam +of light falls on the long and tortuous paths by which man rose to his +supremacy long before the drama of human life had been chronicled or +sung. + +Of the strides taken by humanity on its way to the summit of terrestrial +life, there are but four worthy of mention as preparing the way for the +victories of the electrician--the attainment of the upright attitude, +the intentional kindling of fire, the maturing of emotional cries to +articulate speech, and the invention of written symbols for speech. As +we examine electricity in its fruitage we shall find that it bears the +unfailing mark of every other decisive factor of human advance: its +mastery is no mere addition to the resources of the race, but a +multiplier of them. The case is not as when an explorer discovers a +plant hitherto unknown, such as Indian corn, which takes its place +beside rice and wheat as a new food, and so measures a service which +ends there. Nor is it as when a prospector comes upon a new metal, such +as nickel, with the sole effect of increasing the variety of materials +from which a smith may fashion a hammer or a blade. Almost infinitely +higher is the benefit wrought when energy in its most useful phase is, +for the first time, subjected to the will of man, with dawning knowledge +of its unapproachable powers. It begins at once to marry the resources +of the mechanic and the chemist, the engineer and the artist, with issue +attested by all its own fertility, while its rays reveal province after +province undreamed of, and indeed unexisting, before its advent. + +Every other primal gift of man rises to a new height at the bidding of +the electrician. All the deftness and skill that have followed from the +upright attitude, in its creation of the human hand, have been brought +to a new edge and a broader range through electric art. Between the uses +of flame and electricity have sprung up alliances which have created new +wealth for the miner and the metal-worker, the manufacturer and the +shipmaster, with new insights for the man of research. Articulate speech +borne on electric waves makes itself heard half-way across America, and +words reduced to the symbols of symbols--expressed in the perforations +of a strip of paper--take flight through a telegraph wire at twenty-fold +the pace of speech. Because the latest leap in knowledge and faculty has +been won by the electrician, he has widened the scientific outlook +vastly more than any explorer who went before. Beyond any predecessor, +he began with a better equipment and a larger capital to prove the +gainfulness which ever attends the exploiting a supreme agent of +discovery. + +As we trace a few of the unending interlacements of electrical science +and art with other sciences and arts, and study their mutually +stimulating effects, we shall be reminded of a series of permutations +where the latest of the factors, because latest, multiplies all prior +factors in an unexampled degree.[5] We shall find reason to believe that +this is not merely a suggestive analogy, but really true as a tendency, +not only with regard to man's gains by the conquest of electricity, but +also with respect to every other signal victory which has brought him to +his present pinnacle of discernment and rule. If this permutative +principle in former advances lay undetected, it stands forth clearly in +that latest accession to skill and interpretation which has been ushered +in by Franklin and Volta, Faraday and Henry. + +Although of much less moment than the triumphs of the electrician, the +discovery of photography ranks second in importance among the scientific +feats of the nineteenth century. The camera is an artificial eye with +almost every power of the human retina, and with many that are denied +to vision--however ingeniously fortified by the lens-maker. A brief +outline of photographic history will show a parallel to the permutative +impulse so conspicuous in the progress of electricity. At the points +where the electrician and the photographer collaborate we shall note +achievements such as only the loftiest primal powers may evoke. + +A brief story of what electricity and its necessary precursor, fire, +have done and promise to do for civilization, may have attraction in +itself; so, also, may a review, though most cursory, of the work of the +camera and all that led up to it: for the provinces here are as wide as +art and science, and their bounds comprehend well-nigh the entirety of +human exploits. And between the lines of this story we may read +another--one which may tell us something of the earliest stumblings in +the dawn of human faculty. When we compare man and his next of kin, we +find between the two a great gulf, surely the widest betwixt any allied +families in nature. Can a being of intellect, conscience, and aspiration +have sprung at any time, however remote, from the same stock as the +orang and the chimpanzee? Since 1859, when Darwin published his "Origin +of Species," the theory of evolution has become so generally accepted +that to-day it is little more assailed than the doctrine of gravitation. +And yet, while the average man of intelligence bows to the formula that +all which now exists has come from the simplest conceivable state of +things,--a universal nebula, if you will,--in his secret soul he makes +one exception--himself. That there is a great deal more assent than +conviction in the world is a chiding which may come as justly from the +teacher's table as from the preacher's pulpit. Now, if we but catch the +meaning of man's mastery of electricity, we shall have light upon his +earlier steps as a fire-kindler, and as a graver of pictures and symbols +on bone and rock. As we thus recede from civilization to primeval +savagery, the process of the making of man may become so clear that the +arguments of Darwin shall be received with conviction, and not with +silent repulse. + +As we proceed to recall, one by one, the salient chapters in the history +of fire, and of the arts of depiction that foreran the camera, we shall +perceive a truth of high significance. We shall see that, while every +new faculty has its roots deep in older powers, and while its growth may +have been going on for age after age, yet its flowering may be as the +event of a morning. Even as our gardens show us the century-plants, once +supposed to bloom only at the end of a hundred years, so history, in the +large, exhibits discoveries whose harvests are gathered only after the +lapse of æons instead of years. The arts of fire were slowly elaborated +until man had produced the crucible and the still, through which his +labours culminated in metals purified, in acids vastly more corrosive +than those of vegetation, in glass and porcelain equally resistant to +flame and the electric wave. These were combined in an hour by Volta to +build his cell, and in that hour began a new era for human faculty and +insight. + +It is commonly imagined that the progress of humanity has been at a +tolerably uniform pace. Our review of that progress will show that here +and there in its course have been _leaps_, as radically new forces have +been brought under the dominion of man. We of the electric revolution +are sharply marked off from our great-grandfathers, who looked upon the +cell of Volta as a curious toy. They, in their turn, were profoundly +differenced from the men of the seventeenth century, who had not learned +that flame could outvie the horse as a carrier, and grind wheat better +than the mill urged by the breeze. And nothing short of an abyss +stretches between these men and their remote ancestors, who had not +found a way to warm their frosted fingers or lengthen with lamp or +candle the short, dark days of winter. + +Throughout the pages of this book there will be some recital of the +victories won by the fire-maker, the electrician, the photographer, and +many more in the peerage of experiment and research. Underlying the +sketch will appear the significant contrast betwixt accessions of minor +and of supreme dignity. The finding a new wood, such as that of the yew, +means better bows for the archer, stronger handles for the tool-maker; +the subjugation of a universal force such as fire, or electricity, +stands for the exaltation of power in every field of toil, for the +creation of a new earth for the worker, new heavens for the thinker. As +a corollary, we shall observe that an increasing width of gap marks off +the successive stages of human progress from each other, so that its +latest stride is much the longest and most decisive. And it will be +further evident that, while every new faculty is of age-long derivation +from older powers and ancient aptitudes, it nevertheless comes to the +birth in a moment, as it were, and puts a strain of probably fatal +severity on those contestants who miss the new gift by however little. +We shall, therefore, find that the principle of permutation, here merely +indicated, accounts in large measure for three cardinal facts in the +history of man: First, his leaps forward; second, the constant +accelerations in these leaps; and third, the gap in the record of the +tribes which, in the illimitable past, have succumbed as forces of a new +edge and sweep have become engaged in the fray.[6] + +The interlacements of the arts of fire and of electricity are intimate +and pervasive. While many of the uses of flame date back to the dawn of +human skill, many more have become of new and higher value within the +last hundred years. Fire to-day yields motive power with tenfold the +economy of a hundred years ago, and motive power thus derived is the +main source of modern electric currents. In metallurgy there has long +been an unwitting preparation for the advent of the electrician, and +here the services of fire within the nineteenth century have won +triumphs upon which the later successes of electricity largely proceed. +In producing alloys, and in the singular use of heat to effect its own +banishment, novel and radical developments have been recorded within the +past decade or two. These, also, make easier and bolder the +electrician's tasks. The opening chapters of this book will, therefore, +bestow a glance at the principal uses of fire as these have been +revealed and applied. This glance will make clear how fire and +electricity supplement each other with new and remarkable gains, while +in other fields, not less important, electricity is nothing else than a +supplanter of the very force which made possible its own discovery and +impressment. + +[Here follow chapters which outline the chief applications of flame and +of electricity.] + +Let us compare electricity with its precursor, fire, and we shall +understand the revolution by which fire is now in so many tasks +supplanted by the electric pulse which, the while, creates for itself a +thousand fields denied to flame. Copper is an excellent thermal +conductor, and yet it transmits heat almost infinitely more slowly than +it conveys electricity. One end of a thick copper rod ten feet long may +be safely held in the hand while the other end is heated to redness, +yet one millionth part of this same energy, if in the form of +electricity, would traverse the rod in one 100,000,000th part of a +second. Compare next electricity with light, often the companion of +heat. Light travels in straight lines only; electricity can go round a +corner every inch for miles, and, none the worse, yield a brilliant beam +at the end of its journey. Indirectly, therefore, electricity enables us +to conduct either heat or light as if both were flexible pencils of +rays, and subject to but the smallest tolls in their travel. + +We have remarked upon such methods as those of the electric welder which +summon intense heat without fire, and we have glanced at the electric +lamps which shine just because combustion is impossible through their +rigid exclusion of air. Then for a moment we paused to look at the +plating baths which have developed themselves into a commanding rivalry +with the blaze of the smelting furnace, with the flame which from time +immemorial has filled the ladle of the founder and moulder. Thus methods +that commenced in dismissing flame end boldly by dispossessing heat +itself. But, it may be said, this usurping electricity usually finds its +source, after all, in combustion under a steam-boiler. True, but mark +the harnessing of Niagara, of the Lachine Rapids near Montreal, of a +thousand streams elsewhere. In the near future motive power of Nature's +giving is to be wasted less and less, and perforce will more and more +exclude heat from the chain of transformations which issue in the +locomotive's flight, in the whirl of factory and mill. Thus in some +degree is allayed the fear, never well grounded, that when the coal +fields of the globe are spent civilization must collapse. As the +electrician hears this foreboding he recalls how much fuel is wasted in +converting heat into electricity. He looks beyond either turbine or +shaft turned by wind or tide, and, remembering that the metal dissolved +in his battery yields at his will its full content of energy, either as +heat or electricity, he asks, Why may not coal or forest tree, which are +but other kinds of fuel, be made to do the same? + +One of the earliest uses of light was a means of communicating +intelligence, and to this day the signal lamp and the red fire of the +mariner are as useful as of old. But how much wider is the field of +electricity as it creates the telegraph and the telephone! In the +telegraph we have all that a pencil of light could be were it as long as +an equatorial girdle and as flexible as a silken thread. In the +telephone for nearly two thousand miles the pulsations of the speaker's +voice are not only audible, but retain their characteristic tones. + +In the field of mechanics electricity is decidedly preferable to any +other agent. Heat may be transformed into motive power by a suitable +engine, but there its adaptability is at an end. An electric current +drives not only a motor, but every machine and tool attached to the +motor, the whole executing tasks of a delicacy and complication new to +industrial art. On an electric railroad an identical current propels the +train, directs it by telegraph, operates its signals, provides it with +light and heat, while it stands ready to give constant verbal +communication with any station on the line, if this be desired. + +In the home electricity has equal versatility, at once promoting +healthfulness, refinement and safety. Its tiny button expels the +hazardous match as it lights a lamp which sends forth no baleful fumes. +An electric fan brings fresh air into the house--in summer as a grateful +breeze. Simple telephones, quite effective for their few yards of wire, +give a better because a more flexible service than speaking-tubes. Few +invalids are too feeble to whisper at the light, portable ear of metal. +Sewing-machines and the more exigent apparatus of the kitchen and +laundry transfer their demands from flagging human muscles to the +tireless sinews of electric motors--which ask no wages when they stand +unemployed. Similar motors already enjoy favour in working the elevators +of tall dwellings in cities. If a householder is timid about burglars, +the electrician offers him a sleepless watchman in the guise of an +automatic alarm; if he has a dread of fire, let him dispose on his walls +an array of thermometers that at the very inception of a blaze will +strike a gong at headquarters. But these, after all, are matters of +minor importance in comparison with the foundations upon which may be +reared, not a new piece of mechanism, but a new science or a new art. + +In the recent swift subjugation of the territory open alike to the +chemist and the electrician, where each advances the quicker for the +other's company, we have fresh confirmation of an old truth--that the +boundary lines which mark off one field of science from another are +purely artificial, are set up only for temporary convenience. The +chemist has only to dig deep enough to find that the physicist and +himself occupy common ground. "Delve from the surface of your sphere to +its heart, and at once your radius joins every other." Even the briefest +glance at electro-chemistry should pause to acknowledge its profound +debt to the new theories as to the bonding of atoms to form molecules, +and of the continuity between solution and electrical dissociation. +However much these hypotheses may be modified as more light is shed on +the geometry and the journeyings of the molecule, they have for the time +being recommended themselves as finder-thoughts of golden value. These +speculations of the chemist carry him back perforce to the days of his +childhood. As he then joined together his black and white bricks he +found that he could build cubes of widely different patterns. It was in +propounding a theory of molecular architecture that Kekulé gave an +impetus to a vast and growing branch of chemical industry--that of the +synthetic production of dyes and allied compounds. + +It was in pure research, in paths undirected to the market-place, that +such theories have been thought out. Let us consider electricity as an +aid to investigation conducted for its own sake. The chief physical +generalization of our time, and of all time, the persistence of force, +emerged to view only with the dawn of electric art. When it was observed +that electricity might become heat, light, chemical action, or +mechanical motion, that in turn any of these might produce electricity, +it was at once indicated that all these phases of energy might differ +from each other only as the movements in circles, volutes, and spirals +of ordinary mechanism. The suggestion was confirmed when electrical +measurers were refined to the utmost precision, and a single quantum of +energy was revealed a very Proteus in its disguises, yet beneath these +disguises nothing but constancy itself. + +"There is that scattereth, and yet increaseth; and there is that +withholdeth more than is meet, but it tendeth to poverty." Because the +geometers of old patiently explored the properties of the triangle, the +circle, and the ellipse, simply for pure love of truth, they laid the +corner-stones for the arts of the architect, the engineer, and the +navigator. In like manner it was the disinterested work of investigation +conducted by Ampère, Faraday, Henry and their compeers, in ascertaining +the laws of electricity which made possible the telegraph, the +telephone, the dynamo, and the electric furnace. The vital relations +between pure research and economic gain have at last worked themselves +clear. It is perfectly plain that a man who has it in him to discover +laws of matter and energy does incomparably more for his kind than if he +carried his talents to the mint for conversion into coin. The voyage of +a Columbus may not immediately bear as much fruit as the uncoverings of +a mine prospector, but in the long run a Columbus makes possible the +finding many mines which without him no prospector would ever see. +Therefore let the seed-corn of knowledge be planted rather than eaten. +But in choosing between one research and another it is impossible to +foretell which may prove the richer in its harvests; for instance, all +attempts thus far economically to oxidize carbon for the production of +electricity have failed, yet in observations that at first seemed +equally barren have lain the hints to which we owe the incandescent lamp +and the wireless telegraph. + +Perhaps the most promising field of electrical research is that of +discharges at high pressures; here the leading American investigators +are Professor John Trowbridge and Professor Elihu Thomson. Employing a +tension estimated at one and a half millions volts, Professor Trowbridge +has produced flashes of lightning six feet in length in atmospheric air; +in a tube exhausted to one-seventh of atmospheric pressure the flashes +extended themselves to forty feet. According to this inquirer, the +familiar rending of trees by lightning is due to the intense heat +developed in an instant by the electric spark; the sudden expansion of +air or steam in the cavities of the wood causes an explosion. The +experiments of Professor Thomson confront him with some of the seeming +contradictions which ever await the explorer of new scientific +territory. In the atmosphere an electrical discharge is facilitated when +a metallic terminal (as a lightning rod) is shaped as a point; under oil +a point is the form least favourable to discharge. In the same line of +paradox it is observed that oil steadily improves in its insulating +effect the higher the electrical pressure committed to its keeping; with +air as an insulator the contrary is the fact. These and a goodly array +of similar puzzles will, without doubt, be cleared up as students in the +twentieth century pass from the twilight of anomaly to the sunshine of +ascertained law. + +"Before there can be applied science there must be science to apply," +and it is by enabling the investigator to know nature under a fresh +aspect that electricity rises to its highest office. The laboratory +routine of ascertaining the conductivity, polarisability, and other +electrical properties of matter is dull and exacting work, but it opens +to the student new windows through which to peer at the architecture of +matter. That architecture, as it rises to his view, discloses one law of +structure after another; what in a first and clouded glance seemed +anomaly is now resolved and reconciled; order displays itself where +once anarchy alone appeared. When the investigator now needs a substance +of peculiar properties he knows where to find it, or has a hint for its +creation--a creation perhaps new in the history of the world. As he +thinks of the wealth of qualities possessed by his store of alloys, +salts, acids, alkalies, new uses for them are borne into his mind. Yet +more--a new orchestration of inquiry is possible by means of the +instruments created for him by the electrician, through the advances in +method which these instruments effect. With a second and more intimate +point of view arrives a new trigonometry of the particle, a trigonometry +inconceivable in pre-electric days. Hence a surround is in progress +which early in the twentieth century may go full circle, making atom and +molecule as obedient to the chemist as brick and stone are to the +builder now. + +The laboratory investigator and the commercial exploiter of his +discoveries have been by turns borrower and lender, to the great profit +of both. What Leyden jar could ever be constructed of the size and +revealing power of an Atlantic cable? And how many refinements of +measurement, of purification of metals, of precision in manufacture, +have been imposed by the colossal investments in deep-sea telegraphy +alone! When a current admitted to an ocean cable, such as that between +Brest and New York, can choose for its path either 3,540 miles of copper +wire or a quarter of an inch of gutta-percha, there is a dangerous +opportunity for escape into the sea, unless the current is of nicely +adjusted strength, and the insulator has been made and laid with the +best-informed skill, the most conscientious care. In the constant tests +required in laying the first cables Lord Kelvin (then Professor William +Thomson) felt the need for better designed and more sensitive +galvanometers or current measurers. His great skill both as a +mathematician and a mechanician created the existing instruments, which +seem beyond improvement. They serve not only in commerce and +manufacture, but in promoting the strictly scientific work of the +laboratory. Now that electricity purifies copper as fire cannot, the +mathematician is able to treat his problems of long-distance +transmission, of traction, of machine design, with an economy and +certainty impossible when his materials were not simply impure, but +impure in varying and indefinite degrees. The factory and the workshop +originally took their magneto-machines from the experimental laboratory; +they have returned them remodelled beyond recognition as dynamos and +motors of almost ideal effectiveness. + +A galvanometer actuated by a thermo-electric pile furnishes much the +most sensitive means of detecting changes of temperature; hence +electricity enables the physicist to study the phenomena of heat with +new ease and precision. It was thus that Professor Tyndall conducted +the classical researches set forth in his "Heat as a Mode of Motion," +ascertaining the singular power to absorb terrestrial heat which makes +the aqueous vapours of the atmosphere act as an indispensable blanket to +the earth. + +And how vastly has electricity, whether in the workshop or laboratory, +enlarged our conceptions of the forces that thrill space, of the +substances, seemingly so simple, that surround us--substances that +propound questions of structure and behaviour that silence the acutest +investigator. "You ask me," said a great physicist, "if I have a theory +of the _universe_? Why, I haven't even a theory of _magnetism_!" + +The conventional phrase "conducting a current" is now understood to be +mere figure of speech; it is thought that a wire does little else than +give direction to electric energy. Pulsations of high tension have been +proved to be mainly superficial in their journeys, so that they are best +conveyed (or convoyed) by conductors of tubular form. And what is it +that moves when we speak of conduction? It seems to be now the molecule +of atomic chemistry, and anon the same ether that undulates with light +or radiant heat. Indeed, the conquest of electricity means so much +because it impresses the molecule and the ether into service as its +vehicles of communication. Instead of the old-time masses of metal, or +bands of leather, which moved stiffly through ranges comparatively +short, there is to-day employed a medium which may traverse 186,400 +miles in a second, and with resistances most trivial in contrast with +those of mechanical friction. + +And what is friction in the last analysis but the production of motion +in undesired forms, the allowing valuable energy to do useless work? In +that amazing case of long distance transmission, common sunshine, a +solar beam arrives at the earth from the sun not one whit the weaker for +its excursion of 92,000,000 miles. It is highly probable that we are +surrounded by similar cases of the total absence of friction in the +phenomena of both physics and chemistry, and that art will come nearer +and nearer to nature in this immunity is assured when we see how many +steps in that direction have already been taken by the electrical +engineer. In a preceding page a brief account was given of the theory +that gases and vapours are in ceaseless motion. This motion suffers no +abatement from friction, and hence we may infer that the molecules +concerned are perfectly elastic. The opinion is gaining ground among +physicists that all the properties of matter, transparency, chemical +combinability, and the rest, are due to immanent motion in particular +orbits, with diverse velocities. If this be established, then these +motions also suffer no friction, and go on without resistance forever. + +As the investigators in the vanguard of science discuss the constitution +of matter, and weave hypotheses more or less fruitful as to the +interplay of its forces, there is a growing faith that the day is at +hand when the tie between electricity and gravitation will be +unveiled--when the reason why matter has weight will cease to puzzle the +thinker. Who can tell what relief of man's estate may be bound up with +the ability to transform any phase of energy into any other without the +circuitous methods and serious losses of to-day! In the sphere of +economic progress one of the supreme advances was due to the invention +of money, the providing a medium for which any salable thing may be +exchanged, with which any purchasable thing may be bought. As soon as a +shell, or a hide, or a bit of metal was recognized as having universal +convertibility, all the delays and discounts of barter were at an end. +In the world of physics and chemistry the corresponding medium is +electricity; let it be produced as readily as it produces other modes of +motion, and human art will take a stride forward such as when Volta +disposed his zinc and silver discs together, or when Faraday set a +magnet moving around a copper wire. + +For all that the electric current is not as yet produced as economically +as it should be, we do wrong if we regard it as an infant force. However +much new knowledge may do with electricity in the laboratory, in the +factory, or in the exchange, some of its best work is already done. It +is not likely ever to perform a greater feat than placing all mankind +within ear-shot of each other. Were electricity unmastered there could +be no democratic government of the United States. To-day the drama of +national affairs is more directly in view of every American citizen +than, a century ago, the public business of Delaware could be to the men +of that little State. And when on the broader stage of international +politics misunderstandings arise, let us note how the telegraph has +modified the hard-and-fast rules of old-time diplomacy. To-day, through +the columns of the press, the facts in controversy are instantly +published throughout the world, and thus so speedily give rise to +authoritative comment that a severe strain is put upon negotiators whose +tradition it is to be both secret and slow. + +Railroads, with all they mean for civilization, could not have extended +themselves without the telegraph to control them. And railroads and +telegraphs are the sinews and nerves of national life, the prime +agencies in welding the diverse and widely separated States and +Territories of the Union. A Boston merchant builds a cotton-mill in +Georgia; a New York capitalist opens a copper-mine in Arizona. The +telegraph which informs them day by day how their investments prosper +tells idle men where they can find work, where work can seek idle men. +Chicago is laid in ashes, Charleston topples in earthquake, Johnstown is +whelmed in flood, and instantly a continent springs to their relief. And +what benefits issue in the strictly commercial uses of the telegraph! +At its click both locomotive and steamship speed to the relief of famine +in any quarter of the globe. In times of plenty or of dearth the markets +of the globe are merged and are brought to every man's door. Not less +striking is the neighbourhood guild of science, born, too, of the +telegraph. The day after Röntgen announced his X rays, physicists on +every continent were repeating his experiments--were applying his +discovery to the healing of the wounded and diseased. Let an anti-toxin +for diphtheria, consumption, or yellow fever be proposed, and a hundred +investigators the world over bend their skill to confirm or disprove, as +if the suggester dwelt next door. + +On a stage less dramatic, or rather not dramatic at all, electricity +works equal good. Its motor freeing us from dependence on the horse is +spreading our towns and cities into their adjoining country. Field and +garden compete with airless streets. The sunny cottage is in active +rivalry with the odious tenement-house. It is found that transportation +within the gates of a metropolis has an importance second only to the +means of transit which links one city with another. The engineer is at +last filling the gap which too long existed between the traction of +horses and that of steam. In point of speed, cleanliness, and comfort +such an electric subway as that of South London leaves nothing to be +desired. Throughout America electric roads, at first suburban, are now +fast joining town to town and city to city, while, as auxiliaries to +steam railroads, they place sparsely settled communities in the arterial +current of the world, and build up a ready market for the dairyman and +the fruit-grower. In its saving of what Mr. Oscar T. Crosby has called +"man-hours" the third-rail system is beginning to oust steam as a motive +power from trunk-lines. Already shrewd railroad managers are granting +partnerships to the electricians who might otherwise encroach upon their +dividends. A service at first restricted to passengers has now extended +itself to the carriage of letters and parcels, and begins to reach out +for common freight. We may soon see the farmer's cry for good roads +satisfied by good electric lines that will take his crops to market much +more cheaply and quickly than horses and macadam ever did. In cities, +electromobile cabs and vans steadily increase in numbers, furthering the +quiet and cleanliness introduced by the trolley car. + +A word has been said about the blessings which electricity promises to +country folk, yet greater are the boons it stands ready to bestow in the +hives of population. Until a few decades ago the water-supply of cities +was a matter not of municipal but of individual enterprise; water was +drawn in large part from wells here and there, from lines of piping laid +in favoured localities, and always insufficient. Many an epidemic of +typhoid fever was due to the contamination of a spring by a cesspool a +few yards away. To-day a supply such as that of New York is abundant +and cheap because it enters every house. Let a centralized electrical +service enjoy a like privilege, and it will offer a current which is +heat, light, chemical energy, or motive power, and all at a wage lower +than that of any other servant. Unwittingly, then, the electrical +engineer is a political reformer of high degree, for he puts a new +premium upon ability and justice at the City Hall. His sole condition is +that electricity shall be under control at once competent and honest. +Let us hope that his plea, joined to others as weighty, may quicken the +spirit of civic righteousness so that some of the richest fruits ever +borne in the garden of science and art may not be proffered in vain. +Flame, the old-time servant, is individual; electricity, its successor +and heir, is collective. Flame sits upon the hearth and draws a family +together; electricity, welling from a public source, may bind into a +unit all the families of a vast city, because it makes the benefit of +each the interest of all. + +But not every promise brought forward in the name of the electrician has +his assent or sanction. So much has been done by electricity, and so +much more is plainly feasible, that a reflection of its triumphs has +gilded many a baseless dream. One of these is that the cheap electric +motor, by supply power at home, will break up the factory system, and +bring back the domestic manufacturing of old days. But if this power +cost nothing at all the gift would leave the factory unassailed; for we +must remember that power is being steadily reduced in cost from year to +year, so that in many industries it has but a minor place among the +expenses of production. The strength and profit of the factory system +lie in its assembling a wide variety of machines, the first delivering +its product to the second for another step toward completion, and so on +until a finished article is sent to the ware-room. It is this minute +subdivision of labour, together with the saving and efficiency that +inure to a business conducted on an immense scale under a single +manager, that bids us believe that the factory has come to stay. To be +sure, a weaver, a potter, or a lens-grinder of peculiar skill may thrive +at his loom or wheel at home; but such a man is far from typical in +modern manufacture. Besides, it is very questionable whether the +lamentations over the home industries of the past do not ignore evil +concomitants such as still linger in the home industries of the +present--those of the sweater's den, for example. + +This rapid survey of what electricity has done and may yet do--futile +expectation dismissed--has shown it the creator of a thousand material +resources, the perfector of that communication of things, of power, of +thought, which in every prior stage of advancement has marked the +successive lifts of humanity. It was much when the savage loaded a pack +upon a horse or an ox instead of upon his own back; it was yet more when +he could make a beacon-flare give news or warning to a whole +country-side, instead of being limited to the messages which might be +read in his waving hands. All that the modern engineer was able to do +with steam for locomotion is raised to a higher plane by the advent of +his new power, while the long-distance transmission of electrical energy +is contracting the dimensions of the planet to a scale upon which its +cataracts in the wilderness drive the spindles and looms of the factory +town, or illuminate the thoroughfares of cities. Beyond and above all +such services as these, electricity is the corner-stone of physical +generalization, a revealer of truths impenetrable by any other ray. + +The subjugation of fire has done much in giving man a new independence +of nature, a mighty armoury against evil. In curtailing the most arduous +and brutalizing forms of toil, electricity, that subtler kind of fire, +carries this emancipation a long step further, and, meanwhile, bestows +upon the poor many a luxury which but lately was the exclusive +possession of the rich. In more closely binding up the good of the bee +with the welfare of the hive, it is an educator and confirmer of every +social bond. In so far as it proffers new help in the war on pain and +disease it strengthens the confidence of man in an Order of Right and +Happiness which for so many dreary ages has been a matter rather of hope +than of vision. Are we not, then, justified in holding electricity to be +a multiplier of faculty and insight, a means of dignifying mind and +soul, unexampled since man first kindled fire and rejoiced? + +We have traced how dexterity rose to fire-making, how fire-making led to +the subjugation of electricity. Much of the most telling work of fire +can be better done by its great successor, while electricity performs +many tasks possible only to itself. Unwitting truth there was in the +simple fable of the captive who let down a spider's film, that drew up a +thread, which in turn brought up a rope--and freedom. It was in 1800 on +the threshold of the nineteenth century, that Volta devised the first +electric battery. In a hundred years the force then liberated has +vitally interwoven itself with every art and science, bearing fruit not +to be imagined even by men of the stature of Watt, Lavoisier, or +Humboldt. Compare this rapid march of conquest with the slow adaptation, +through age after age, of fire to cooking, smelting, tempering. Yet it +was partly, perhaps mainly, because the use of fire had drawn out man's +intelligence and cultivated his skill that he was ready in the fulness +of time so quickly to seize upon electricity and subdue it. + +Electricity is as legitimately the offspring of fire as fire of the +simple knack in which one savage in ten thousand was richer than his +fellows. The principle of permutation, suggested in both victories, +interprets not only how vast empire is won by a new weapon of prime +dignity; it explains why such empires are brought under rule with +ever-accelerated pace. Every talent only pioneers the way for the +richer talents which are born from it. + + +FOOTNOTES: + +[5] Permutations are the various ways in which two or more different +things may be arranged in a row, all the things appearing in each row. +Permutations are readily illustrated with squares or cubes of different +colours, with numbers, or letters. + +Permutations of two elements, 1 and 2, are (1 x 2) two; 1, 2; 2, 1; or +_a_, _b_; _b_, _a_. Of three elements the permutations are (1 x 2 x 3) +six; 1, 2, 3; 1, 3, 2; 2, 1, 3; 2, 3, 1; 3, 1, 2; 3, 2, 1; or _a_, _b_, +_c_; _a_, _c_, _b_; _b_, _a_, _c_; _b_, _c_, _a_; _c_, _a_, _b_; _c_, +_b_, _a_. Of four elements the permutations are (1 x 2 x 3 x 4) +twenty-four; of five elements, one hundred and twenty, and so on. A new +element or permutator multiplies by an increasing figure all the +permutations it finds. + +[6] Some years ago I sent an outline of this argument to Herbert +Spencer, who replied: "I recognize a novelty and value in your inference +that the law implies an increasing width of gap between lower and higher +types as evolution advances." + + + + +COUNT RUMFORD IDENTIFIES HEAT WITH MOTION. + + [Benjamin Thompson, who received the title of Count Rumford from + the Elector of Bavaria, was born in Woburn, Massachusetts, in 1753. + When thirty-one years of age he settled in Munich, where he devoted + his remarkable abilities to the public service. Twelve years + afterward he removed to England; in 1800 he founded the Royal + Institution of London, since famous as the theatre of the labours + of Davy, Faraday, Tyndall, and Dewar. He bequeathed to Harvard + University a fund to endow a professorship of the application of + science to the art of living: he instituted a prize to be awarded + by the American Academy of Sciences for the most important + discoveries and improvements relating to heat and light. In 1804 he + married the widow of the illustrious chemist Lavoisier: he died in + 1814. Count Rumford on January 25, 1798, read a paper before the + Royal Society entitled "An Enquiry Concerning the Source of Heat + Which Is Excited by Friction." The experiments therein detailed + proved that heat is identical with motion, as against the notion + that heat is matter. He thus laid the corner-stone of the modern + theory that heat light, electricity, magnetism, chemical action, + and all other forms of energy are in essence motion, are + convertible into one another, and as motion are indestructible. The + following abstract of Count Rumford's paper is taken from "Heat as + a Mode of Motion," by Professor John Tyndall, published by D. + Appleton & Co., New York. This work and "The Correlation and + Conservation of Forces," edited by Dr. E. L. Youmans, published by + the same house, will serve as a capital introduction to the modern + theory that energy is motion which, however varied in its forms, is + changeless in its quantity.] + + +Being engaged in superintending the boring of cannon in the workshops of +the military arsenal at Munich, Count Rumford was struck with the very +considerable degree of heat which a brass gun acquires, in a short time, +in being bored, and with the still more intense heat (much greater than +that of boiling water) of the metallic chips separated from it by the +borer, he proposed to himself the following questions: + +"Whence comes the heat actually produced in the mechanical operations +above mentioned? + +"Is it furnished by the metallic chips which are separated from the +metal?" + +If this were the case, then the _capacity for heat_ of the parts of the +metal so reduced to chips ought not only to be changed, but the change +undergone by them should be sufficiently great to account for _all_ the +heat produced. No such change, however, had taken place, for the chips +were found to have the same capacity as slices of the same metal cut by +a fine saw, where heating was avoided. Hence, it is evident, that the +heat produced could not possibly have been furnished at the expense of +the latent heat of the metallic chips. Rumford describes these +experiments at length, and they are conclusive. + +He then designed a cylinder for the express purpose of generating heat +by friction, by having a blunt borer forced against its solid bottom, +while the cylinder was turned around its axis by the force of horses. To +measure the heat developed, a small round hole was bored in the +cylinder for the purpose of introducing a small mercurial thermometer. +The weight of the cylinder was 113.13 pounds avoirdupois. + +The borer was a flat piece of hardened steel, 0.63 of an inch thick, +four inches long, and nearly as wide as the cavity of the bore of the +cylinder, namely, three and one-half inches. The area of the surface by +which its end was in contact with the bottom of the bore was nearly two +and one-half inches. At the beginning of the experiment the temperature +of the air in the shade, and also that of the cylinder, was 60° Fahr. At +the end of thirty minutes, and after the cylinder had made 960 +revolutions round its axis, the temperature was found to be 130°. + +Having taken away the borer, he now removed the metallic dust, or rather +scaly matter, which had been detached from the bottom of the cylinder by +the blunt steel borer, and found its weight to be 837 grains troy. "Is +it possible," he exclaims, "that the very considerable quantity of heat +produced in this experiment--a quantity which actually raised the +temperature of above 113 pounds of gun-metal at least 70° of +Fahrenheit's thermometer--could have been furnished by so inconsiderable +a quantity of metallic dust and this merely in consequence of a _change_ +in its capacity of heat?" + +"But without insisting on the improbability of this supposition, we have +only to recollect that from the results of actual and decisive +experiments, made for the express purpose of ascertaining that fact, +the capacity for heat for the metal of which great guns are cast is _not +sensibly changed_ by being reduced to the form of metallic chips, and +there does not seem to be any reason to think that it can be much +changed, if it be changed at all, in being reduced to much smaller +pieces by a borer which is less sharp." + +He next surrounded his cylinder by an oblong deal-box, in such a manner +that the cylinder could turn water-tight in the centre of the box, while +the borer was pressed against the bottom of the cylinder. The box was +filled with water until the entire cylinder was covered, and then the +apparatus was set in action. The temperature of the water on commencing +was 60°. + +"The result of this beautiful experiment," writes Rumford, "was very +striking, and the pleasure it afforded me amply repaid me for all the +trouble I had had in contriving and arranging the complicated machinery +used in making it. The cylinder had been in motion but a short time, +when I perceived, by putting my hand into the water, and touching the +outside of the cylinder, that heat was generated. + +"At the end of one hour the fluid, which weighed 18.77 pounds, or two +and one-half gallons, had its temperature raised forty-seven degrees, +being now 107°. + +"In thirty minutes more, or one hour and thirty minutes after the +machinery had been set in motion, the heat of the water was 142°. + +"At the end of two hours from the beginning, the temperature was 178°. + +"At two hours and twenty minutes it was 200°, and at two hours and +thirty minutes it _actually boiled_!" + +"It would be difficult to describe the surprise and astonishment +expressed in the countenances of the bystanders on seeing so large a +quantity of water heated, and actually made to boil, without any fire. +Though, there was nothing that could be considered very surprising in +this matter, yet I acknowledge fairly that it afforded me a degree of +childish pleasure which, were I ambitious of the reputation of a grave +philosopher, I ought most certainly rather to hide than to discover." + +He then carefully estimates the quantity of heat possessed by each +portion of his apparatus at the conclusion of the experiment, and, +adding all together, finds a total sufficient to raise 26.58 pounds of +ice-cold water to its boiling point, or through 180° Fahrenheit. By +careful calculation, he finds this heat equal to that given out by the +combustion of 2,303.8 grains (equal to four and eight-tenths ounces +troy) of wax. + +He then determines the "_celerity_" with which the heat was generated, +summing up thus: "From the results of these computations, it appears +that the quantity of heat produced equably, or in a continuous stream, +if I may use the expression, by the friction of the blunt steel borer +against the bottom of the hollow metallic cylinder, was _greater_ than +that produced in the combustion of nine _wax-candles_, each +three-quarters of an inch in diameter, all burning together with clear +bright flames. + +"One horse would have been equal to the work performed, though two were +actually employed. Heat may thus be produced merely by the strength of a +horse, and, in a case of necessity, this heat might be used in cooking +victuals. But no circumstances could be imagined in which this method of +procuring heat would be advantageous, for more heat might be obtained by +using the fodder necessary for the support of a horse as fuel." + +[This is an extremely significant passage, intimating as it does, that +Rumford saw clearly that the force of animals was derived from the food; +_no creation of force_ taking place in the animal body.] + +"By meditating on the results of all these experiments, we are naturally +brought to that great question which has so often been the subject of +speculation among philosophers, namely, What is heat--is there any such +thing as an _igneous fluid_? Is there anything that, with propriety, can +be called caloric? + +"We have seen that a very considerable quantity of heat may be excited +by the friction of two metallic surfaces, and given off in a constant +stream or flux _in all directions_, without interruption or +intermission, and without any signs of _diminution_ or _exhaustion_. In +reasoning on this subject we must not forget _that most remarkable +circumstance_, that the source of the heat generated by friction in +these experiments appeared evidently to be _inexhaustible_. [The italics +are Rumford's.] It is hardly necessary to add, that anything which any +_insulated_ body or system of bodies can continue to furnish _without +limitation_ cannot possibly be a _material substance_; and it appears to +me to be extremely difficult, if not quite impossible, to form any +distinct idea of anything capable of being excited and communicated in +those experiments, except it be MOTION." + +When the history of the dynamical theory of heat is written, the man +who, in opposition to the scientific belief of his time, could +experiment and reason upon experiment, as Rumford did in the +investigation here referred to, cannot be lightly passed over. Hardly +anything more powerful against the materiality of heat has been since +adduced, hardly anything more conclusive in the way of establishing that +heat is, what Rumford considered it to be, _Motion_. + + + + +VICTORY OF THE "ROCKET" LOCOMOTIVE. + + [Part of Chapter XII. Part II, of "The Life of George Stephenson + and of His Son, Robert Stephenson," by Samuel Smiles New York, + Harper & Brothers, 1868.] + + +The works of the Liverpool and Manchester Railway were now approaching +completion. But, strange to say, the directors had not yet decided as to +the tractive power to be employed in working the line when open for +traffic. The differences of opinion among them were so great as +apparently to be irreconcilable. It was necessary, however, that they +should, come to some decision without further loss of time, and many +board meetings were accordingly held to discuss the subject. The +old-fashioned and well-tried system of horse-haulage was not without its +advocates; but, looking at the large amount of traffic which there was +to be conveyed, and at the probable delay in the transit from station to +station if this method were adopted, the directors, after a visit made +by them to the Northumberland and Durham railways in 1828, came to the +conclusion that the employment of horse-power was inadmissible. + +Fixed engines had many advocates; the locomotive very few: it stood as +yet almost in a minority of one--George Stephenson.... + +In the meantime the discussion proceeded as to the kind of power to be +permanently employed for the working of the railway. The directors were +inundated with schemes of all sorts for facilitating locomotion. The +projectors of England, France, and America seemed to be let loose upon +them. There were plans for working the waggons along the line by +water-power. Some proposed hydrogen, and others carbonic acid gas. +Atmospheric pressure had its eager advocates. And various kinds of fixed +and locomotive steam-power were suggested. Thomas Gray urged his plan of +a greased road with cog-rails; and Messrs. Vignolles and Ericsson +recommended the adoption of a central friction-rail, against which two +horizontal rollers under the locomotive, pressing upon the sides of this +rail, were to afford the means of ascending the inclined planes.... + +The two best practical engineers of the day concurred in reporting +substantially in favour of the employment of fixed engines. Not a single +professional man of eminence could be found to coincide with the +engineer of the railway in his preference for locomotive over fixed +engine power. He had scarcely a supporter, and the locomotive system +seemed on the eve of being abandoned. Still he did not despair. With the +profession against him, and public opinion against him--for the most +frightful stories went abroad respecting the dangers, the unsightliness, +and the nuisance which the locomotive would create--Stephenson held to +his purpose. Even in this, apparently the darkest hour of the +locomotive, he did not hesitate to declare that locomotive railroads +would, before many years had passed, be "the great highways of the +world." + +He urged his views upon the directors in all ways, in season, and, as +some of them thought, out of season. He pointed out the greater +convenience of locomotive power for the purposes of a public highway, +likening it to a series of short unconnected chains, any one of which +could be removed and another substituted without interruption to the +traffic; whereas the fixed-engine system might be regarded in the light +of a continuous chain extending between the two termini, the failure of +any link of which would derange the whole. But the fixed engine party +was very strong at the board, and, led by Mr. Cropper, they urged the +propriety of forthwith adopting the report of Messrs. Walker and +Rastrick. Mr. Sandars and Mr. William Rathbone, on the other hand, +desired that a fair trial should be given to the locomotive; and they +with reason objected to the expenditure of the large capital necessary +to construct the proposed engine-houses, with their fixed engines, +ropes, and machinery, until they had tested the powers of the locomotive +as recommended by their own engineer. George Stephenson continued to +urge upon them that the locomotive was yet capable of great +improvements, if proper inducements were held out to inventors and +machinists to make them; and he pledged himself that, if time were +given him, he would construct an engine that should satisfy their +requirements, and prove itself capable of working heavy loads along the +railway with speed, regularity, and safety. At length, influenced by his +persistent earnestness not less than by his arguments, the directors, at +the suggestion of Mr. Harrison, determined to offer a prize of £500 for +the best locomotive engine, which, on a certain day, should be produced +on the railway, and perform certain specified conditions in the most +satisfactory manner.[7] + +The requirements of the directors as to speed were not excessive. All +that they asked for was that ten miles an hour should be maintained. +Perhaps they had in mind the animadversions of the _Quarterly Review_ on +the absurdity of travelling at a greater velocity, and also the remarks +published by Mr. Nicholas Wood, whom they selected to be one of the +judges of the competition, in conjunction, with Mr. Rastrick, of +Stourbridge, and Mr. Kennedy, of Manchester. + +It was now felt that the fate of railways in a great measure depended +upon the issue of this appeal to the mechanical genius of England. When +the advertisement of the prize for the best locomotive was published, +scientific men began more particularly to direct their attention to the +new power which was thus struggling into existence. In the meantime +public opinion on the subject of railway working remained suspended, and +the progress of the undertaking was watched with intense interest. + +During the progress of this important controversy with reference to the +kind of power to be employed in working the railway, George Stephenson +was in constant communication with his son Robert, who made frequent +visits to Liverpool for the purpose of assisting his father in the +preparation of his reports to the board on the subject. Mr. Swanwick +remembers the vivid interest of the evening discussions which then took +place between father and son as to the best mode of increasing the +powers and perfecting the mechanism of the locomotive. He wondered at +their quick perception and rapid judgment on each other's suggestions; +at the mechanical difficulties which they anticipated and provided for +in the practical arrangement of the machine; and he speaks of these +evenings as most interesting displays of two actively ingenious and able +minds stimulating each other to feats of mechanical invention, by which +it was ordained that the locomotive engine should become what it now is. +These discussions became more frequent, and still more interesting, +after the public prize had been offered for the best locomotive by the +directors of the railway, and the working plans of the engine which they +proposed to construct had to be settled. + +One of the most important considerations in the new engine was the +arrangement of the boiler, and the extension of its heating surface to +enable steam enough to be raised rapidly and continuously for the +purpose of maintaining high rates of speed--the effect of high pressure +engines being ascertained to depend mainly upon the quantity of steam +which the boiler can generate, and upon its degree of elasticity when +produced. The quantity of steam so generated, it will be obvious, must +chiefly depend upon the quantity of fuel consumed in the furnace, and, +by necessary consequence, upon the high rate of temperature maintained +there. + +It will be remembered that in Stephenson's first Killingworth engines he +invited and applied the ingenious method of stimulating combustion in +the furnace by throwing the waste steam into the chimney after +performing its office in the cylinders, thereby accelerating the ascent +of the current of air, greatly increasing the draught, and consequently +the temperature of the fire. This plan was adopted by him, as we have +seen, as early as 1815, and it was so successful that he himself +attributed to it the greater economy of the locomotive as compared with +horse-power. Hence the continuance of its use upon the Killingworth +Railway. + +Though the adoption of the steam blast greatly quickened combustion and +contributed to the rapid production of high-pressure steam, the limited +amount of heating surface presented to the fire was still felt to be an +obstacle to the complete success of the locomotive engine. Mr. +Stephenson endeavoured to overcome this by lengthening the boilers and +increasing the surface presented by the flue-tubes. The "Lancashire +Witch," which he built for the Bolton and Leigh Railway, and used in +forming the Liverpool and Manchester Railway embankments, was +constructed with a double tube, each of which contained a fire, and +passed longitudinally through the boiler. But this arrangement +necessarily led to a considerable increase in the weight of those +engines, which amounted to about twelve tons each; and as six tons was +the limit allowed for engines admitted to the Liverpool competition, it +was clear that the time was come when the Killingworth engine must +undergo a farther important modification. + +For many years previous to this period, ingenious mechanics had been +engaged in attempting to solve the problem of the best and most +economical boiler for the production of high-pressure steam. + +The use of tubes in boilers for increasing the heating surface had long +been known. As early as 1780, Matthew Boulton employed copper tubes +longitudinally in the boiler of the Wheal Busy engine in Cornwall--the +fire passing _through_ the tubes--and it was found that the production +of steam was thereby considerably increased. The use of tubular boilers +afterwards became common in Cornwall. In 1803, Woolf, the Cornish +engineer, patented a boiler with tubes, with the same object of +increasing the heating surface. The water was _inside_ the tubes, and +the fire of the boiler outside. Similar expedients were proposed by +other inventors. In 1815 Trevithick invented his light high-pressure +boiler for portable purposes, in which, to "expose a large surface to +the fire," he constructed the boiler of a number of small perpendicular +tubes "opening into a common reservoir at the top." In 1823 W. H. James +contrived a boiler composed of a series of annular wrought-iron tubes, +placed side by side and bolted together, so as to form by their union a +long cylindrical boiler, in the centre of which, at the end, the +fireplace was situated. The fire played round the tubes, which contained +the water. In 1826 James Neville took out a patent for a boiler with +vertical tubes surrounded by the water, through which the heated air of +the furnace passed, explaining also in his specification that the tubes +might be horizontal or inclined, according to circumstances. Mr. +Goldsworthy, the persevering adaptor of steam-carriages to travelling on +common roads, applied the tubular principle in the boiler of his engine, +in which the steam was generated _within_ the tubes; while the boiler +invented by Messrs. Summer and Ogle for their turnpike-road +steam-carriage consisted of a series of tubes placed vertically over the +furnace, through which the heated air passed before reaching the +chimney. + +About the same time George Stephenson was trying the effect of +introducing small tubes in the boilers of his locomotives, with the +object of increasing their evaporative power. Thus, in 1829, he sent to +France two engines constructed at the Newcastle works for the Lyons and +St. Etienne Railway, in the boilers of which tubes were placed +containing water. The heating surface was thus considerably increased; +but the expedient was not successful, for the tubes, becoming furred +with deposit, shortly burned out and were removed. It was then that M. +Seguin, the engineer of the railway, pursuing the same idea, is said to +have adopted his plan of employing horizontal tubes through which the +heated air passed in streamlets, and for which he took out a French +patent. + +In the meantime Mr. Henry Booth, secretary to the Liverpool and +Manchester Railway, whose attention had been directed to the subject on +the prize being offered for the best locomotive to work that line, +proposed the same method, which, unknown to him, Matthew Boulton had +employed but not patented, in 1780, and James Neville had patented, but +not employed, in 1826; and it was carried into effect by Robert +Stephenson in the construction of the "Rocket," which won the prize at +Rainhill in October, 1829. The following is Mr. Booth's account in a +letter to the author: + +"I was in almost daily communication with Mr. Stephenson at the time, +and I was not aware that he had any intention of competing for the prize +till I communicated to him my scheme of a multitubular boiler. This new +plan of boiler comprised the introduction of numerous small tubes, two +or three inches in diameter, and less than one-eighth of an inch thick, +through which to carry the fire instead of a single tube or flue +eighteen inches in diameter, and about half an inch thick, by which +plan we not only obtain a very much larger heating surface, but the +heating surface is much more effective, as there intervenes between the +fire and the water only a thin sheet of copper or brass, not an eighth +of an inch thick, instead of a plate of iron of four times the +substance, as well as an inferior conductor of heat. + +"When the conditions of trial were published, I communicated my +multitubular plan to Mr. Stephenson, and proposed to him that we should +jointly construct an engine and compete for the prize. Mr. Stephenson +approved the plan, and agreed to my proposal. He settled the mode in +which the fire-box and tubes were to be mutually arranged and connected, +and the engine was constructed at the works of Messrs. Robert Stephenson +& Co., Newcastle-on-Tyne. + +"I am ignorant of M. Seguin's proceedings in France, but I claim to be +the inventor in England, and feel warranted in stating, without +reservation, that until I named my plan to Mr. Stephenson, with a view +to compete for the prize at Rainhill, it had not been tried, and was not +known in this country." + +From the well-known high character of Mr. Booth, we believe his +statement to be made in perfect good faith, and that he was as much in +ignorance of the plan patented by Neville as he was of that of Seguin. +As we have seen, from the many plans of tubular boilers invented during +the preceding thirty years, the idea was not by any means new; and we +believe Mr. Booth to be entitled to the merit of inventing the method by +which the multitubular principle was so effectually applied in the +construction of the famous "Rocket" engine. + +The principal circumstances connected with the construction of the +"Rocket," as described by Robert Stephenson to the author, may be +briefly stated. The tubular principle was adopted in a more complete +manner than had yet been attempted. Twenty-five copper tubes, each three +inches in diameter, extended from one end of the boiler to the other, +the heated air passing through them on its way to the chimney; and the +tubes being surrounded by the water of the boiler, it will be obvious +that a large extension of the heating surface was thus effectually +secured. The principal difficulty was in fitting the copper tubes in the +boiler ends so as to prevent leakage. They were manufactured by a +Newcastle coppersmith, and soldered to brass screws which were screwed +into the boiler ends, standing out in great knobs. When the tubes were +thus fitted, and the boiler was filled with water, hydraulic pressure +was applied; but the water squirted out at every joint, and the factory +floor was soon flooded. Robert went home in despair; and in the first +moment of grief he wrote to his father that the whole thing was a +failure. By return of post came a letter from his father, telling him +that despair was not to be thought of--that he must "try again;" and he +suggested a mode of overcoming the difficulty, which his son had +already anticipated and proceeded to adopt. It was, to bore clean holes +in the boiler ends, fit in the smooth copper tubes as tightly as +possible, solder up, and then raise the steam. This plan succeeded +perfectly, the expansion of the copper tubes completely filling up all +interstices, and producing a perfectly water-tight boiler, capable of +withstanding extreme external pressure. + +The mode of employing the steam-blast for the purpose of increasing the +draught in the chimney was also the subject of numerous experiments. +When the engine was first tried, it was thought that the blast in the +chimney was not sufficiently strong for the purpose of keeping up the +intensity of fire in the furnace, so as to produce high-pressure steam +with the required velocity. The expedient was therefore adopted of +hammering the copper tubes at the point at which they entered the +chimney, whereby the blast was considerably sharpened; and on a farther +trial it was found that the draught was increased to such an extent as +to enable abundance of steam to be raised. The rationale of the blast +may be simply explained by referring to the effect of contracting the +pipe of a water-hose, by which the force of the jet of water is +proportionately increased. Widen the nozzle of the pipe, and the jet is +in like manner diminished. So it is with the steam-blast in the chimney +of the locomotive. + +Doubts were, however, expressed whether the greater draught obtained by +the contraction of the blast-pipe was not counterbalanced in some degree +by the negative pressure upon the piston. Hence a series of experiments +was made with pipes of different diameters, and their efficiency was +tested by the amount of vacuum that was produced in the smoke-box. The +degree of rarefaction was determined by a glass tube fixed to the bottom +of the smoke-box and descending into a bucket of water, the tube being +open at both ends. As the rarefaction took place, the water would, of +course, rise in the tube, and the height to which it rose above the +surface of the water in the bucket was made the measure of the amount of +rarefaction. These experiments proved that a considerable increase of +draught was obtained by the contraction of the orifice; accordingly, the +two blast-pipes opening from the cylinders into either side of the +"Rocket" chimney, and turned up within it, were contracted slightly +below the area of the steam-ports, and before the engine left the +factory, the water rose in the glass tube three inches above the water +in the bucket. + +The other arrangements of the "Rocket" were briefly these: the boiler +was cylindrical, with flat ends, six feet in length, and three feet four +inches in diameter. The upper half of the boiler was used as a reservoir +for the steam, the lower half being filled with water. Through the lower +part the copper tubes extended, being open to the fire-box at one end, +and to the chimney at the other. The fire-box, or furnace, two feet wide +and three feet high, was attached immediately behind the boiler, and was +also surrounded with water. The cylinders of the engine were placed on +each side of the boiler, in an oblique position, one end being nearly +level with the top of the boiler at its after end, and the other +pointing toward the centre of the foremost or driving pair of wheels, +with which the connection was directly made from the piston-rod to a pin +on the outside of the wheel. The engine, together with its load of +water, weighed only four tons and a quarter; and it was supported on +four wheels, not coupled. The tender was four-wheeled, and similar in +shape to a waggon--the foremost part holding the fuel, and the hind part +a water cask. + +When the "Rocket" was finished it was placed upon the Killingworth +Railway for the purpose of experiment. The new boiler arrangement was +found perfectly successful. The steam was raised rapidly and +continuously, and in a quantity which then appeared marvellous. The same +evening Robert despatched a letter to his father at Liverpool, informing +him, to his great joy, that the "Rocket" was "all right," and would be +in complete working trim by the day of trial. The engine was shortly +after sent by waggon to Carlisle, and thence shipped for Liverpool. + +The time so much longed for by George Stephenson had now arrived, when +the merits of the passenger locomotive were about to be put to the +test. He had fought the battle for it until now almost single-handed. +Engrossed by his daily labours and anxieties, and harassed by +difficulties and discouragements which would have crushed the spirit of +a less resolute man, he had held firmly to his purpose through good and +through evil report. The hostility which he experienced from some of the +directors opposed to the adoption of the locomotive was the circumstance +that caused him the greatest grief of all; for where he had looked for +encouragement, he found only carping and opposition. But his pluck never +failed him; and now the "Rocket" was upon the ground to prove, to use +his own words, "whether he was a man of his word or not." + +On the day appointed for the great competition of locomotives at +Rainhill the following engines were entered for the prize: + +1. Messrs. Braithwaite and Ericsson's "Novelty." + +2. Mr. Timothy Hackworth's "Sanspareil." + +3. Messrs. R. Stephenson & Co.'s "Rocket." + +4. Mr. Burstall's "Perseverance." + +The ground on which the engines were to be tried was a level piece of +railroad, about two miles in length. Each was required to make twenty +trips, or equal to a journey of seventy miles, in the course of the day, +and the average rate of travelling was to be not under ten miles an +hour. It was determined that, to avoid confusion, each engine should be +tried separately, and on different days. + +The day fixed for the competition was the 1st of October, but, to allow +sufficient time to get the locomotives into good working order, the +directors extended it to the 6th. It was quite characteristic of the +Stephensons that, although their engine did not stand first on the list +for trial, it was the first that was ready, and it was accordingly +ordered out by the judges for an experimental trip. Yet the "Rocket" was +by no means the "favourite" with either the judges or the spectators. +Nicholas Wood has since stated that the majority of the judges were +strongly predisposed in favour of the "Novelty," and that "nine-tenths, +if not ten-tenths, of the persons present were against the "Rocket" +because of its appearance." Nearly every person favoured some other +engine, so that there was nothing for the "Rocket" but the practical +test. The first trip made by it was quite successful. It ran about +twelve miles, without interruption, in about fifty-three minutes. + +The "Novelty" was next called out. It was a light engine, very compact +in appearance, carrying the water and fuel upon the same wheels as the +engine. The weight of the whole was only three tons and one +hundred-weight. A peculiarity of this engine was that the air was driven +or _forced_ through the fire by means of bellows. The day being now far +advanced, and some dispute having arisen as to the method of assigning +the proper load for the "Novelty," no particular experiment was made +further than that the engine traversed the line by way of exhibition, +occasionally moving at the rate of twenty-four miles an hour. The +"Sanspareil," constructed by Mr. Timothy Hackworth, was next exhibited, +but no particular experiment was made with it on this day. This engine +differed but little in its construction from the locomotive last +supplied by the Stephensons to the Stockton and Darlington Railway, of +which Mr. Hackworth was the locomotive foreman. + +The contest was postponed until the following day; but, before the +judges arrived on the ground, the bellows for creating the blast in the +"Novelty" gave way, and it was found incapable of going through its +performance. A defect was also detected in the boiler of the +"Sanspareil," and some further time was allowed to get it repaired. The +large number of spectators who had assembled to witness the contest were +greatly disappointed at this postponement; but, to lessen it, Stephenson +again brought out the "Rocket," and, attaching it to a coach containing +thirty persons, he ran them along the line at a rate of from twenty-four +to thirty miles an hour, much to their gratification and amazement. +Before separating, the judges ordered the engine to be in readiness by +eight o'clock on the following morning, to go through its definite trial +according to the prescribed conditions. + +On the morning of the 8th of October the "Rocket" was again ready for +the contest. The engine was taken to the extremity of the stage, the +fire-box was filled with coke, the fire lighted, and the steam raised +until it lifted the safety-valve loaded to a pressure of fifty pounds to +the square inch. This proceeding occupied fifty-seven minutes. The +engine then started on its journey, dragging after it about thirteen +tons' weight in waggons, and made the first ten trips backward and +forward along two miles of road, running the thirty-five miles, +including stoppages, in an hour and forty-eight minutes. The second ten +trips were in like manner performed in two hours and three minutes. The +maximum velocity attained during the trial trip was twenty-nine miles an +hour, or about three times the speed that one of the judges of the +competition had declared to be the limit of possibility. The average +speed at which the whole of the journeys was performed was fifteen miles +an hour, or five miles beyond the rate specified in the conditions +published by the company. The entire performance excited the greatest +astonishment among the assembled spectators; the directors felt +confident that their enterprise was now on the eve of success; and +George Stephenson rejoiced to think that, in spite of all false prophets +and fickle counsellors, the locomotive system was now safe. When the +"Rocket," having performed all the conditions of the contest, arrived at +the "grand stand" at the close of its day's successful run, Mr. +Cropper--one of the directors favourable to the fixed engine +system--lifted up his hands, and exclaimed, "Now has George Stephenson +at last delivered himself...." + +The "Rocket" had eclipsed the performance of all locomotive engines that +had yet been constructed, and outstripped even the sanguine expectations +of its constructors. It satisfactorily answered the report of Messrs. +Walker and Rastrick, and established the efficiency of the locomotive +for working the Liverpool and Manchester Railway, and, indeed, all +future railways. The "Rocket" showed that a new power had been born into +the world, full of activity and strength, with boundless capability of +work. It was the simple but admirable contrivance of the steam-blast, +and its combination with the multitubular boiler, that at once gave +locomotion a vigorous life, and secured the triumph of the railway +system.[8] + +[Illustration: The "Rocket"] + + +FOOTNOTES: + +[7] The conditions were these: + +1. The engine must effectually consume its own smoke. + +2. The engine, if of six tons' weight, must be able to draw after it, +day by day, twenty tons' weight (including the tender and water-tank) at +_ten miles_ an hour, with a pressure of steam on the boiler not +exceeding fifty pounds to the square inch. + +3. The boiler must have two safety-valves, neither of which must be +fastened down, and one of them be completely out of the control of the +engine-man. + +4. The engine and boiler must be supported on springs, and rest on six +wheels, the height of the whole not exceeding fifteen feet to the top of +the chimney. + +5. The engine, with water, must not weigh more than six tons; but an +engine of less weight would be preferred on its drawing a proportionate +load behind it; if of only four and a half tons, then it might be put on +only four wheels. The company will be at liberty to test the boiler, +etc., by a pressure of one hundred and fifty pounds to the square inch. + +6. A mercurial gauge must be affixed to the machine, showing the steam +pressure above forty-five pounds per square inch. + +7. The engine must be delivered, complete and ready for trial, at the +Liverpool end of the railway, not later than the 1st of October, 1829. + +8. The price of the engine must not exceed £550. + +Many persons of influence declared the conditions published by the +directors of the railway chimerical in the extreme. One gentleman of +some eminence in Liverpool, Mr. P. Ewart, who afterward filled the +office of Government Inspector of Post-office Steam Packets, declared +that only a parcel of charlatans would ever have issued such a set of +conditions; that it had been _proved_ to be impossible to make a +locomotive engine go at ten miles an hour; but if it ever was done, he +would undertake to eat a stewed engine-wheel for his breakfast. + +[8] When heavier and more powerful engines were brought upon the road, +the old "Rocket," becoming regarded as a thing of no value, was sold in +1837. It has since been transferred to the Museum of Patents at South +Kensington, London, where it is still to be seen. + + +Transcriber's Notes: + +Page 30--imployed changed to employed. + +Page 31--subsequenty changed to subsequently. + +Page 47--build changed to building. + +Page 147--suggestor changed to suggester. + +Page 166--supgestion changed to suggestion. + +Footnote 7--Changed question mark for a period. + +Inconsistencies in hyphenated words have been made consistent. + +Obvious printer errors, including punctuation, have been corrected +without note. + + + + + +End of Project Gutenberg's Little Masterpieces of Science:, by Various + +*** END OF THIS PROJECT GUTENBERG EBOOK LITTLE MASTERPIECES OF SCIENCE: *** + +***** This file should be named 29241-8.txt or 29241-8.zip ***** +This and all associated files of various formats will be found in: + http://www.gutenberg.org/2/9/2/4/29241/ + +Produced by Sigal Alon, Marcia Brooks, Fox in the Stars +and the Online Distributed Proofreading Team at +http://www.pgdp.net + + +Updated editions will replace the previous one--the old editions +will be renamed. + +Creating the works from public domain print editions means that no +one owns a United States copyright in these works, so the Foundation +(and you!) can copy and distribute it in the United States without +permission and without paying copyright royalties. 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You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Little Masterpieces of Science: + Invention and Discovery + +Author: Various + +Editor: George Iles + +Release Date: June 25, 2009 [EBook #29241] + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK LITTLE MASTERPIECES OF SCIENCE: *** + + + + +Produced by Sigal Alon, Marcia Brooks, Fox in the Stars +and the Online Distributed Proofreading Team at +http://www.pgdp.net + + + + + + +</pre> + + + +<h1>LITTLE MASTERPIECES OF SCIENCE</h1> + +<div class="figcenter" style="width: 305px;"> +<img src="images/il004.png" width="305" height="500" alt="George Stephenson." title="George Stephenson." /> +<span class="caption">George Stephenson.</span> +</div> +<br /><br /> + +<div class="bbox"> +<h1>Little Masterpieces<br /> +of Science</h1> + +<h2>Edited by George Iles</h2> +</div> +<div class="bbox"> +<br /> +<br /> +<h1>INVENTION AND DISCOVERY</h1> +<br /> +<h3><i>By</i></h3> + +<div class='center'> +<table border="0" cellpadding="4" cellspacing="0" summary="Authors"> +<tr><td align='left'>Benjamin Franklin</td><td align='left'>Alexander Graham Bell</td></tr> +<tr><td align='left'>Michael Faraday</td><td align='left'>Count Rumford</td></tr> +<tr><td align='left'>Joseph Henry</td><td align='left'>George Stephenson</td></tr> +</table></div> +<br /> +<div class="figcenter" style="width: 125px;"> +<img src="images/il005.png" width="125" height="116" alt="Decoration" title="Decoration" /> +</div> + +</div> +<div class="bbox"> +<h5>NEW YORK</h5> +<h4>DOUBLEDAY, PAGE & COMPANY</h4> +<h5>1902</h5> +</div> +<br /><br /> + +<div class="center"> +Copyright, 1902, by Doubleday, Page & Co.<br /> +Copyright, 1877, by George B. Prescott<br /> +Copyright, 1896, by S. S. McClure Co.<br /> +Copyright, 1900, by Doubleday, McClure & Co.<br /> +</div> + + + +<hr /> +<h2>PREFACE</h2> + + +<p>To a good many of us the inventor is the true +hero for he multiplies the working value of +life. He performs an old task with new economy, +as when he devises a mowing-machine to +oust the scythe; or he creates a service wholly +new, as when he bids a landscape depict itself on +a photographic plate. He, and his twin brother, +the discoverer, have eyes to read a lesson that +Nature has held for ages under the undiscerning +gaze of other men. Where an ordinary observer +sees, or thinks he sees, diversity, a Franklin detects +identity, as in the famous experiment here +recounted which proves lightning to be one and +the same with a charge of the Leyden jar. Of a +later day than Franklin, advantaged therefor +by new knowledge and better opportunities for +experiment, stood Faraday, the founder of +modern electric art. His work gave the world the +dynamo and motor, the transmission of giant +powers, almost without toll, for two hundred +miles at a bound. It is, however, in the carriage +of but trifling quantities of motion, just enough +for signals, that electricity thus far has done its +most telling work. Among the men who have +created the electric telegraph Joseph Henry has +a commanding place. A short account of what +he did, told in his own words, is here presented. +Then follows a narrative of the difficult task of +laying the first Atlantic cables, a task long +scouted as impossible: it is a story which proves +how much science may be indebted to unfaltering +courage, to faith in ultimate triumph.</p> + +<p>To give speech the wings of electricity, to +enable friends in Denver and New York to converse +with one another, is a marvel which only +familiarity places beyond the pale of miracle. +Shortly after he perfected the telephone Professor +Bell described the steps which led to its +construction. That recital is here reprinted.</p> + +<p>A recent wonder of electric art is its penetration +by a photographic ray of substances until now +called opaque. Professor Röntgen's account of +how he wrought this feat forms one of the +most stirring chapters in the history of science. +Next follows an account of the telegraph as it +dispenses with metallic conductors altogether, +and trusts itself to that weightless ether which +brings to the eye the luminous wave. To this +succeeds a chapter which considers what electricity +stands for as one of the supreme resources +of human wit, a resource transcending even flame +itself, bringing articulate speech and writing to +new planes of facility and usefulness. It +is shown that the rapidity with which during +a single century electricity has been subdued for +human service, illustrates that progress has leaps +as well as deliberate steps, so that at last a gulf, +all but infinite, divides man from his next of kin.</p> + +<p>At this point we pause to recall our debt to the +physical philosophy which underlies the calculations +of the modern engineer. In such an experiment +as that of Count Rumford we observe +how the corner-stone was laid of the knowledge +that heat is motion, and that motion under whatever +guise, as light, electricity, or what not, is +equally beyond creation or annihilation, however +elusively it may glide from phase to phase and +vanish from view. In the mastery of Flame for +the superseding of muscle, of breeze and waterfall, +the chief credit rests with James Watt, +the inventor of the steam engine. Beside him +stands George Stephenson, who devised the locomotive +which by abridging space has lengthened +life and added to its highest pleasures. Our +volume closes by narrating the competition +which decided that Stephenson's “Rocket” +was much superior to its rivals, and thus opened +a new chapter in the history of mankind.</p> + +<p style="text-align: right;"><span class="smcap">George Iles.</span></p> + +<hr /> +<a name="toc" id="toc"></a> +<h2>CONTENTS</h2> + +<div class="center"> +<table border="0" cellpadding="4" cellspacing="0" summary="Table of Contents" width="80%"> +<colgroup> + <col width="90%" /> + <col width="10%" /> +</colgroup> +<tr> +<td class="tdh">FRANKLIN, BENJAMIN</td> +</tr> +<tr> +<td align='center'><a href="#FRANKLIN_IDENTIFIES_LIGHTNING"><b><span class="smcap">Lightning Identified with Electricity</span></b></a></td> +</tr> +<tr> +<td><p class="hang">Franklin explains the action of the Leyden phial or jar. + Suggests lightning-rods. Sends a kite into the clouds during + a thunderstorm; through the kite-string obtains a spark + of lightning which throws into divergence the loose fibres + of the string, just as an ordinary electrical discharge + would do.</p></td> + <td align='right'><a href="#Page_3">3</a></td> +</tr> +<tr> +<td class="tdh">FARADAY, MICHAEL</td> +</tr> +<tr> +<td align='center'><a href="#FARADAYS_DISCOVERIES_LEADING_UP"><b><span class="smcap">Preparing the Way for the Electric Dynamo and Motor</span></b></a></td> +</tr> +<tr> +<td><p class="hang">Notices the inductive effect in one coil when the circuit in + a concentric coil is completed or broken. Notices similar + effects when a wire bearing a current approaches another + wire or recedes from it. Rotates a galvanometer needle by + an electric pulse. Induces currents in coils when the magnetism + is varied in their iron or steel cores. Observes the lines + of magnetic force as iron filings are magnetized. A magnetic + bar moved in and out of a coil of wire excites electricity + therein,—mechanical motion is converted into electricity. + Generates a current by spinning a copper plate in a horizontal plane.</p></td> + <td align='right'><a href="#Page_7">7</a></td> +</tr> +<tr> +<td class="tdh">HENRY, JOSEPH</td> +</tr> +<tr> +<td align='center'><a href="#PROFESSOR_JOSEPH_HENRYS_INVENTION"><b><span class="smcap">Invention of the Electric Telegraph</span></b></a></td> +</tr> +<tr> +<td><p class="hang">Improves the electro-magnet of Sturgeon by insulating its + wire with silk thread, and by disposing the wire in several + coils instead of one. Experiments with a large electro-magnet + excited by nine distinct coils. Uses a battery so powerful + that electro-magnets are produced one hundred times more + energetic than those of Sturgeon. Arranges a telegraphic + circuit more than a mile long and at that distance sounds + a bell by means of an electro-magnet.</p></td> + <td align='right'><a href="#Page_23">23</a></td> +</tr> +<tr> +<td class="tdh">ILES, GEORGE</td> +</tr> +<tr> +<td align='center'><a href="#THE_FIRST_ATLANTIC_CABLES"><b><span class="smcap">The First Atlantic Cables</span></b></a></td> +</tr> +<tr> +<td><p class="hang">Forerunners at New York and Dover. Gutta-percha the indispensable + insulator. Wire is used to sheathe the cables. Cyrus W. + Field's project for an Atlantic cable. The first cable fails. + 1858 so does the second cable 1865. A triumph of courage, + 1866. The highway smoothed for successors. Lessons of the cable.</p></td> + <td align='right'><a href="#Page_37">37</a></td> +</tr> +<tr> +<td class="tdh">BELL, ALEXANDER GRAHAM</td> +</tr> +<tr> +<td align='center'><a href="#BELLS_TELEPHONIC_RESEARCHES"><b><span class="smcap">The Invention of the Telephone</span></b></a></td> +</tr> +<tr> +<td><p class="hang">Indebted to his father's study of the vocal organs as they + form sounds. Examines the Helmholtz method for the analysis + and synthesis of vocal sounds. Suggests the electrical actuation + of tuning-forks and the electrical transmission of their + tones. Distinguishes intermittent, pulsatory and undulatory + currents. Devises as his first articulating telephone a harp + of steel rods thrown into vibration by electro-magnetism. + Exhibits optically the vibrations of sound, using a preparation + of a human ear: is struck by the efficiency of a slight + aural membrane. Attaches a bit of clock spring to a piece + of goldbeater's skin, speaks to it, an audible message is + received at a distant and similar device. This contrivance + improved is shown at the Centennial Exhibition, Philadelphia, + 1876. At first the same kind of instrument transmitted and + delivered, a message; soon two distinct instruments were + invented for transmitting and for receiving. Extremely small + magnets suffice. A single blade of grass forms a telephonic circuit.</p></td> + <td align='right'><a href="#Page_57">57</a></td> +</tr> +<tr> +<td class="tdh">DAM, H. J. W.</td> +</tr> +<tr> +<td align='center'><a href="#PHOTOGRAPHING_THE_UNSEEN_THE"><b><span class="smcap">Photographing the Unseen</span></b></a></td> +</tr> +<tr> +<td><p class="hang">Röntgen indebted to the researches of Faraday, Clerk-Maxwell, + Hertz, Lodge and Lenard. The human optic nerve is affected + by a very small range in the waves that exist in the ether. + Beyond the visible spectrum of common light are vibrations + which have long been known as heat or as photographically + active. Crookes in a vacuous bulb produced soft light from + high tension electricity. Lenard found that rays from a + Crookes' tube passed through substances opaque to common + light. Röntgen extended these experiments and used the rays + photographically, taking pictures of the bones of the hand + through living flesh, and so on.</p></td> + <td align='right'><a href="#Page_87">87</a></td> +</tr> +<tr> +<td class="tdh">ILES, GEORGE</td> +</tr> +<tr> +<td align='center'><a href="#THE_WIRELESS_TELEGRAPH"><b><span class="smcap">The Wireless Telegraph</span></b></a></td> +</tr> +<tr> +<td><p class="hang">What may follow upon electric induction. Telegraphy to a + moving train. The Preece induction method; its limits. + Marconi's system. His precursors, Hertz, Onesti, Branly + and Lodge. The coherer and the vertical wire form the essence + of the apparatus. Wireless telegraphy at sea.</p></td> + <td align='right'><a href="#Page_109">109</a></td> +</tr> +<tr> +<td class="tdh">ILES, GEORGE</td> +</tr> +<tr> +<td align='center'><a href="#ELECTRICITY_WHAT_ITS_MASTERY"><b><span class="smcap">Electricity, What Its Mastery Means: With a Review and a Prospect</span></b></a></td> +</tr> +<tr> +<td><p class="hang">Electricity does all that fire ever did, does it better, + and performs uncounted services impossible to flame. Its + mastery means as great a forward stride as the subjugation + of fire. A minor invention or discovery simply adds to human + resources: a supreme conquest as of flame or electricity, + is a multiplier and lifts art and science to a new plane. + Growth is slow, flowering is rapid: progress at times is + so quick of pace as virtually to become a leap. The mastery + of electricity based on that of fire. Electricity vastly + wider of range than heat: it is energy in its most available + and desirable phase. The telegraph and the telephone contrasted + with the signal fire. Electricity as the servant of mechanic + and engineer. Household uses of the current. Electricity + as an agent of research now examines Nature in fresh aspects. + The investigator and the commercial exploiter render aid to + one another. Social benefits of electricity, in telegraphy, in + quick travel. The current should serve every city house.</p></td> + <td align='right'><a href="#Page_125">125</a></td> +</tr> +<tr> +<td class="tdh">RUMFORD, COUNT (BENJAMIN THOMPSON)</td> +</tr> +<tr> +<td align='center'><a href="#COUNT_RUMFORD_IDENTIFIES_HEAT"><b><span class="smcap">Heat and Motion Identified</span></b></a></td> +</tr> +<tr> +<td><p class="hang">Observes that in boring a cannon much heat is generated: + the longer the boring lasts, the more heat is produced. He + argues that since heat without limit may be thus produced + by motion, heat must be motion.</p></td> + <td align='right'><a href="#Page_155">155</a></td> +</tr> +<tr> +<td class="tdh">STEPHENSON, GEORGE</td> +</tr> +<tr> +<td align='center'><a href="#VICTORY_OF_THE_ROCKET_LOCOMOTIVE"><b><span class="smcap">The “Rocket” Locomotive and Its Victory</span></b></a></td> +</tr> +<tr> +<td><p class="hang">Shall it be a system of stationary engines or locomotives? + The two best practical engineers of the day are in favour + of stationary engines. A test of locomotives is, however, + proffered, and George Stephenson and his son, Robert, discuss + how they may best build an engine to win the first prize. + They adopt a steam blast to stimulate the draft of the furnace, + and raise steam quickly in a boiler having twenty-five small + fire-tubes of copper. The “Rocket” with a maximum speed of + twenty-nine miles an hour distances its rivals. With its + load of water its weight was but four and a quarter tons.</p></td> + <td align='right'><a href="#Page_163">163</a></td> +</tr> +</table></div> + + +<hr /> +<p><span class='pagenum'><a name="Page_1" id="Page_1">[Pg 1]</a></span></p> +<h1>INVENTION AND DISCOVERY</h1> + + +<p><span class='pagenum'><a name="Page_3" id="Page_3">[Pg 3]</a></span></p> +<span class="totoc"><a href="#toc">Top</a></span> +<h2><a name="FRANKLIN_IDENTIFIES_LIGHTNING" id="FRANKLIN_IDENTIFIES_LIGHTNING"></a>FRANKLIN IDENTIFIES LIGHTNING<br /> +WITH ELECTRICITY</h2> + +<div class="noteb"><p>[From Franklin's Works, edited in ten volumes by John +Bigelow, Vol. I, pages 276-281, copyright by G. P. Putnam's +Sons, New York.]</p></div> + + +<p>Dr. Stuber, the author of the first continuation +of Franklin's life, gives this account of the +electrical experiments of Franklin:—</p> + +<p>“His observations he communicated, in a +series of letters, to his friend Collinson, the first +of which is dated March 28, 1747. In these he +shows the power of points in drawing and throwing +off the electrical matter, which had hitherto +escaped the notice of electricians. He also +made the grand discovery of a <i>plus</i> and <i>minus</i>, +or of a <i>positive</i> and <i>negative</i> state of electricity. +We give him the honour of this without hesitation; +although the English have claimed it for +their countryman, Dr. Watson. Watson's paper +is dated January 21, 1748; Franklin's July 11, +1747, several months prior. Shortly after +Franklin, from his principles of the <i>plus</i> and +<i>minus</i> state, explained in a satisfactory manner +the phenomena of the Leyden phial, first observed +by Mr. Cuneus, or by Professor Muschenbroeck, +of Leyden, which had much perplexed +philosophers. He showed clearly that when +charged the bottle contained no more electricity<span class='pagenum'><a name="Page_4" id="Page_4">[Pg 4]</a></span> +than before, but that as much was taken from +one side as thrown on the other; and that to +discharge it nothing was necessary but to produce +a communication between the two sides by +which the equilibrium might be restored, and +that then no signs of electricity would remain. +He afterwards demonstrated by experiments +that the electricity did not reside in the coating +as had been supposed, but in the pores of the +glass itself. After the phial was charged he +removed the coating, and found that upon applying +a new coating the shock might still be received. +In the year 1749, he first suggested +his idea of explaining the phenomena of thunder +gusts and of <i>aurora borealis</i> upon electric +principles. He points out many particulars in +which lightning and electricity agree; and he +adduces many facts, and reasonings from facts, +in support of his positions.</p> + +<p>“In the same year he conceived the astonishingly +bold and grand idea of ascertaining the +truth of his doctrine by actually drawing down +the lightning, by means of sharp pointed iron +rods raised into the regions of the clouds. Even +in this uncertain state his passion to be useful +to mankind displayed itself in a powerful manner. +Admitting the identity of electricity and +lightning, and knowing the power of points in +repelling bodies charged with electricity, and in +conducting fires silently and imperceptibly, he +suggested the idea of securing houses, ships and +the like from being damaged by lightning, by<span class='pagenum'><a name="Page_5" id="Page_5">[Pg 5]</a></span> +erecting pointed rods that should rise some feet +above the most elevated part, and descend some +feet into the ground or water. The effect of +these he concluded would be either to prevent +a stroke by repelling the cloud beyond the striking +distance or by drawing off the electrical fire +which it contained; or, if they could not effect this +they would at least conduct the electrical matter +to the earth without any injury to the building.</p> + +<p>“It was not until the summer of 1752 that he +was enabled to complete his grand and unparalleled +discovery by experiment. The plan which +he had originally proposed was, to erect, on some +high tower or elevated place, a sentry-box from +which should rise a pointed iron rod, insulated +by being fixed in a cake of resin. Electrified +clouds passing over this would, he conceived, +impart to it a portion of their electricity which +would be rendered evident to the senses by sparks +being emitted when a key, the knuckle, or other +conductor, was presented to it. Philadelphia +at this time afforded no opportunity of trying +an experiment of this kind. While Franklin was +waiting for the erection of a spire, it occurred to +him that he might have more ready access to the +region of clouds by means of a common kite. +He prepared one by fastening two cross sticks +to a silk handkerchief, which would not suffer +so much from the rain as paper. To the upright +stick was affixed an iron point. The string was, +as usual, of hemp, except the lower end, which +was silk. Where the hempen string terminated,<span class='pagenum'><a name="Page_6" id="Page_6">[Pg 6]</a></span> +a key was fastened. With this apparatus, on +the appearance of a thundergust approaching, +he went out into the commons, accompanied by +his son, to whom alone he communicated his +intentions, well knowing the ridicule which, too +generally for the interest of science, awaits unsuccessful +experiments in philosophy. He placed +himself under a shed, to avoid the rain; his kite +was raised, a thunder-cloud passed over it, no +sign of electricity appeared. He almost despaired +of success, when suddenly he observed +the loose fibres of his string to move towards an +erect position. He now presented his knuckle +to the key and received a strong spark. How +exquisite must his sensations have been at this +moment! On his experiment depended the fate +of his theory. If he succeeded, his name would +rank high among those who had improved +science; if he failed, he must inevitably be subjected +to the derision of mankind, or, what is +worse, their pity, as a well-meaning man, but a +weak, silly projector. The anxiety with which +he looked for the result of his experiment may +easily be conceived. Doubts and despair had +begun to prevail, when the fact was ascertained, +in so clear a manner, that even the most incredulous +could no longer withhold their assent. Repeated +sparks were drawn from the key, a phial +was charged, a shock given, and all the experiments +made which are usually performed with +electricity.”</p> + + + +<h2><a name="FARADAYS_DISCOVERIES_LEADING_UP" id="FARADAYS_DISCOVERIES_LEADING_UP"></a>FARADAY'S DISCOVERIES LEADING UP<br /> +TO THE ELECTRIC DYNAMO<br /> +AND MOTOR</h2> +<p><span class='pagenum'><a name="Page_7" id="Page_7">[Pg 7]</a></span></p> +<span class="totoc"><a href="#toc">Top</a></span> + +<div class="noteb"><p>[Michael Faraday was for many years Professor of Natural +Philosophy at the Royal Institution, London, where his +researches did more to subdue electricity to the service of +man than those of any other physicist who ever lived. “Faraday +as a Discoverer,” by Professor John Tyndall (his successor) +depicts a mind of the rarest ability and a character +of the utmost charm. This biography is published by +D. Appleton & Co., New York: the extracts which follow +are from the third chapter.]</p></div> + + +<p>In 1831 we have Faraday at the climax of his +intellectual strength, forty years of age, stored +with knowledge and full of original power. +Through reading, lecturing, and experimenting, +he had become thoroughly familiar with electrical +science: he saw where light was needed and +expansion possible. The phenomena of ordinary +electric induction belonged, as it were, to the +alphabet of his knowledge: he knew that under ordinary +circumstances the presence of an electrified +body was sufficient to excite, by induction, an +unelectrified body. He knew that the wire +which carried an electric current was an electrified +body, and still that all attempts had failed +to make it excite in other wires a state similar +to its own.</p> + +<p>What was the reason of this failure? Faraday<span class='pagenum'><a name="Page_8" id="Page_8">[Pg 8]</a></span> +never could work from the experiments of others, +however clearly described. He knew well that +from every experiment issues a kind of radiation, +luminous, in different degrees to different minds, +and he hardly trusted himself to reason upon an +experiment that he had not seen. In the autumn +of 1831 he began to repeat the experiments +with electric currents, which, up to that time, +had produced no positive result. And here, for +the sake of younger inquirers, if not for the sake +of us all, it is worth while to dwell for a moment +on a power which Faraday possessed in an extraordinary +degree. He united vast strength with +perfect flexibility. His momentum was that +of a river, which combines weight and directness +with the ability to yield to the flexures of its bed. +The intentness of his vision in any direction did +not apparently diminish his power of perception +in other directions; and when he attacked a subject, +expecting results, he had the faculty of +keeping his mind alert, so that results different +from those which he expected should not escape +him through pre-occupation.</p> + +<p>He began his experiments “on the induction +of electric currents” by composing a helix of two +insulated wires, which were wound side by side +round the same wooden cylinder. One of these +wires he connected with a voltaic battery of ten +cells, and the other with a sensitive galvanometer. +When connection with the battery was made, +and while the current flowed, no effect whatever +was observed at the galvanometer. But<span class='pagenum'><a name="Page_9" id="Page_9">[Pg 9]</a></span> +he never accepted an experimental result, until he +had applied to it the utmost power at his command. +He raised his battery from ten cells to +one hundred and twenty cells, but without avail. +The current flowed calmly through the battery +wire without producing, during its flow, any +sensible result upon the galvanometer.</p> + +<p>“During its flow,” and this was the time when +an effect was expected—but here Faraday's +power of lateral vision, separating, as it were +from the line of expectation, came into play—he +noticed that a feeble movement of the needle +always occurred at the moment when he made +contact with the battery; that the needle would +afterwards return to its former position and remain +quietly there unaffected by the <i>flowing</i> +current. At the moment, however, when the +circuit was interrupted the needle again moved, +and in a direction opposed to that observed on +the completion of the circuit.</p> + +<p>This result, and others of a similar kind, led +him to the conclusion “that the battery current +through the one wire did in reality induce a +similar current through the other; but that it +continued for an instant only, and partook more +of the nature of the electric wave from a common +Leyden jar than of the current from a voltaic +battery.” The momentary currents thus generated +were called <i>induced currents</i>, while the +current which generated them was called the +<i>inducing</i> current. It was immediately proved +that the current generated at making the circuit<span class='pagenum'><a name="Page_10" id="Page_10">[Pg 10]</a></span> +was always opposed in direction to its generator, +while that developed on the rupture of the circuit +coincided in direction with the inducing +current. It appeared as if the current on its +first rush through the primary wire sought a purchase +in the secondary one, and, by a kind of +kick, impelled backward through the latter an +electric wave, which subsided as soon as the +primary current was fully established.</p> + +<p>Faraday, for a time, believed that the secondary +wire, though quiescent when the primary +current had been once established, was not in its +natural condition, its return to that condition +being declared by the current observed at breaking +the circuit. He called this hypothetical +state of the wire the <i>electro-tonic state</i>: he afterwards +abandoned this hypothesis, but seemed to +return to it in after life. The term electro-tonic +is also preserved by Professor Du Bois Reymond +to express a certain electric condition of the +nerves, and Professor Clerk Maxwell has ably +defined and illustrated the hypothesis in the +Tenth Volume of the “Transactions of the Cambridge +Philosophical Society.”</p> + +<p>The mere approach of a wire forming a closed +curve to a second wire through which a voltaic +current flowed was then shown by Faraday to be +sufficient to arouse in the neutral wire an induced +current, opposed in direction to the inducing +current; the withdrawal of the wire also generated +a current having the same direction as the +inducing current; those currents existed only<span class='pagenum'><a name="Page_11" id="Page_11">[Pg 11]</a></span> +during the time of approach or withdrawal, and +when neither the primary nor the secondary wire +was in motion, no matter how close their proximity +might be, no induced current was generated.</p> + +<p>Faraday has been called a purely inductive +philosopher. A great deal of nonsense is, I fear, +uttered in this land of England about induction +and deduction. Some profess to befriend the +one, some the other, while the real vocation of +an investigator, like Faraday, consists in the incessant +marriage of both. He was at this time +full of the theory of Ampère, and it cannot be +doubted that numbers of his experiments were +executed merely to test his deductions from +that theory. Starting from the discovery of +Oersted, the celebrated French philosopher had +shown that all the phenomena of magnetism then +known might be reduced to the mutual attractions +and repulsions of electric currents. Magnetism +had been produced from electricity, and Faraday, +who all his life long entertained a strong belief in +such reciprocal actions, now attempted to effect +the evolution of electricity from magnetism. +Round a welded iron ring he placed two distinct +coils of covered wire, causing the coils to occupy +opposite halves of the ring. Connecting the ends +of one of the coils with a galvanometer, he found +that the moment the ring was magnetized, by +sending a current through <i>the other coil</i>, the galvanometer +needle whirled round four or five +times in succession. The action, as before, was +that of a pulse, which vanished immediately.<span class='pagenum'><a name="Page_12" id="Page_12">[Pg 12]</a></span> +On interrupting the current, a whirl of the needle +in the opposite direction occurred. It was only +during the time of magnetization or demagnetization +that these effects were produced. The induced +currents declared a <i>change</i> of condition +only, and they vanished the moment the act of +magnetization or demagnetization was complete.</p> + +<p>The effects obtained with the welded ring were +also obtained with straight bars of iron. Whether +the bars were magnetized by the electric current, +or were excited by the contact of permanent steel +magnets, induced currents were always generated +during the rise, and during the subsidence +of the magnetism. The use of iron was then +abandoned, and the same effects were obtained +by merely thrusting a permanent steel magnet +into a coil of wire. A rush of electricity through +the coil accompanied the insertion of the magnet; +an equal rush in the opposite direction accompanied +its withdrawal. The precision with +which Faraday describes these results, and the +completeness with which he defined the boundaries +of his facts, are wonderful. The magnet, +for example, must not be passed quite through +the coil, but only half through, for if passed +wholly through, the needle is stopped as by a +blow, and then he shows how this blow results +from a reversal of the electric wave in the helix. +He next operated with the powerful permanent +magnet of the Royal Society, and obtained with +it, in an exalted degree, all the foregoing phenomena.<span class='pagenum'><a name="Page_13" id="Page_13">[Pg 13]</a></span></p> + +<p>And now he turned the light of these discoveries +upon the darkest physical phenomenon of +that day. Arago had discovered in 1824, that +a disk of non-magnetic metal had the power of +bringing a vibrating magnetic needle suspended +over it rapidly to rest; and that on causing the +disk to rotate the magnetic needle rotated along +with it. When both were quiescent, there was +not the slightest measurable attraction or repulsion +exerted between the needle and the disk; +still when in motion the disk was competent +to drag after it, not only a light needle, but a +heavy magnet. The question had been probed +and investigated with admirable skill by both +Arago and Ampère, and Poisson had published a +theoretic memoir on the subject; but no cause +could be assigned for so extraordinary an action. +It had also been examined in this country by +two celebrated men, Mr. Babbage and Sir John +Herschel; but it still remained a mystery. Faraday +always recommended the suspension of +judgment in cases of doubt. “I have always +admired,” he says, “the prudence and philosophical +reserve shown by M. Arago in resisting +the temptations to give a theory of the effect he +had discovered, so long as he could not devise one +which was perfect in its application, and in refusing +to assent to the imperfect theories of +others.” Now, however, the time for theory +had come. Faraday saw mentally the rotating +disk, under the operation of the magnet, flooded +with his induced currents, and from the known<span class='pagenum'><a name="Page_14" id="Page_14">[Pg 14]</a></span> +laws of interaction between currents and magnets +he hoped to deduce the motion observed by +Arago. That hope he realized, showing by +actual experiment that when his disk rotated +currents passed through it, their position and +direction being such as must, in accordance with +the established laws of electro-magnetic action, +produce the observed rotation.</p> + +<p>Introducing the edge of his disk between the +poles of the large horseshoe magnet of the Royal +Society, and connecting the axis and the edge +of the disk, each by a wire with a galvanometer, +he obtained, when the disk was turned round, +a constant flow of electricity. The direction of +the current was determined by the direction of +the motion, the current being reversed when the +rotation was reversed. He now states the law +which rules the production of currents in both +disks and wires, and in so doing uses, for the +first time, a phrase which has since become +famous. When iron filings are scattered over a +magnet, the particles of iron arrange themselves +in certain determined lines called magnetic curves. +In 1831, Faraday for the first time called these +curves “lines of magnetic force;” and he showed +that to produce induced currents neither approach +to nor withdrawal from a magnetic source, or +centre, or pole, was essential, but that it was +only necessary to cut appropriately the lines of +magnetic force. Faraday's first paper on +Magneto-electric Induction, which I have +here endeavoured to condense, was read<span class='pagenum'><a name="Page_15" id="Page_15">[Pg 15]</a></span> +before the Royal Society on the 24th of +November, 1831.</p> + +<p>On January 12, 1832, he communicated to the +Royal Society a second paper on “Terrestrial +Magneto-electric Induction,” which was chosen +as the Bakerian Lecture for the year. He placed +a bar of iron in a coil of wire, and lifting the bar +into the direction of the dipping needle, he excited +by this action a current in the coil. On +reversing the bar, a current in the opposite direction +rushed through the wire. The same effect +was produced, when, on holding the helix in the +line of dip, a bar of iron was thrust into it. Here, +however, the earth acted on the coil through +the intermediation of the bar of iron. He +abandoned the bar and simply set a copper-plate +spinning in a horizontal plane; he knew that the +earth's lines of magnetic force then crossed the +plate at an angle of about 70°. When the plate +spun round, the lines of force were intersected +and induced currents generated, which produced +their proper effect when carried from the plate to +the galvanometer. “When the plate was in the +magnetic meridian, or in any other plane coinciding +with the magnetic dip, then its rotation produced +no effect upon the galvanometer.”</p> + +<p>At the suggestion of a mind fruitful in suggestions +of a profound and philosophic character—I +mean that of Sir John Herschel—Mr. Barlow, +of Woolwich, had experimented with a rotating +iron shell. Mr. Christie had also performed an +elaborate series of experiments on a rotating<span class='pagenum'><a name="Page_16" id="Page_16">[Pg 16]</a></span> +iron disk. Both of them had found that when +in rotation the body exercised a peculiar action +upon the magnetic needle, deflecting it in a manner +which was not observed during quiescence; +but neither of them was aware at the time of the +agent which produced this extraordinary deflection. +They ascribed it to some change in the +magnetism of the iron shell and disk.</p> + +<p>But Faraday at once saw that his induced +currents must come into play here, and he immediately +obtained them from an iron disk. With +a hollow brass ball, moreover, he produced the +effects obtained by Mr. Barlow. Iron was in no +way necessary: the only condition of success was +that the rotating body should be of a character +to admit of the formation of currents in its substance: +it must, in other words, be a conductor +of electricity. The higher the conducting power +the more copious were the currents. He now +passes from his little brass globe to the globe of +the earth. He plays like a magician with the +earth's magnetism. He sees the invisible lines +along which its magnetic action is exerted and +sweeping his wand across these lines evokes this +new power. Placing a simple loop of wire round +a magnetic needle he bends its upper portion to +the west: the north pole of the needle immediately +swerves to the east: he bends his loop to +the east, and the north poles moves to the west. +Suspending a common bar magnet in a vertical +position, he causes it to spin round its own axis. +Its pole being connected with one end of a galvanometer<span class='pagenum'><a name="Page_17" id="Page_17">[Pg 17]</a></span> +wire, and its equator with the other +end, electricity rushes round the galvanometer +from the rotating magnet. He remarks upon +the “<i>singular independence</i>” of the magnetism +and the body of the magnet which carries it. +The steel behaves as if it were isolated from its +own magnetism.</p> + +<p>And then his thoughts suddenly widen, and +he asks himself whether the rotating earth does +not generate induced currents as it turns round +its axis from west to east. In his experiment +with the twirling magnet the galvanometer wire +remained at rest; one portion of the circuit was +in motion <i>relatively</i> to <i>another portion</i>. But in +the case of the twirling planet the galvanometer +wire would necessarily be carried along with the +earth; there would be no relative motion. What +must be the consequence? Take the case of a +telegraph wire with its two terminal plates +dipped into the earth, and suppose the wire to lie +in the magnetic meridian. The ground underneath +the wire is influenced like the wire itself by +the earth's rotation; if a current from south to +north be generated in the wire, a similar current +from south to north would be generated in the +earth under the wire; these currents would run +against the same terminal plates, and thus neutralize +each other.</p> + +<p>This inference appears inevitable, but his +profound vision perceived its possible invalidity. +He saw that it was at least possible that the difference +of conducting power between the earth<span class='pagenum'><a name="Page_18" id="Page_18">[Pg 18]</a></span> +and the wire might give one an advantage over +the other, and that thus a residual or differential +current might be obtained. He combined wires +of different materials, and caused them to act in +opposition to each other, but found the combination +ineffectual. The more copious flow in the +better conductor was exactly counterbalanced +by the resistance of the worst. Still, though +experiment was thus emphatic, he would clear +his mind of all discomfort by operating on the +earth itself. He went to the round lake near +Kensington Palace, and stretched four hundred +and eighty feet of copper wire, north and south, +over the lake, causing plates soldered to the wire +at its ends to dip into the water. The copper +wire was severed at the middle, and the severed +ends connected with a galvanometer. No +effect whatever was observed. But though +quiescent water gave no effect, moving water +might. He therefore worked at London Bridge +for three days during the ebb and flow of the +tide, but without any satisfactory result. Still +he urges, “Theoretically it seems a necessary consequence, +that where water is flowing there electric +currents should be formed. If a line be imagined +passing from Dover to Calais through the +sea, and returning through the land, beneath the +water, to Dover, it traces out a circuit of conducting +matter one part of which, when the +water moves up or down the channel, is cutting +the magnetic curves of the earth, while the other +is relatively at rest.... There is every<span class='pagenum'><a name="Page_19" id="Page_19">[Pg 19]</a></span> +reason to believe that currents do run in the +general direction of the circuit described, either +one way or the other, according as the passage of +the waters is up or down the channel.” This +was written before the submarine cable was +thought of, and he once informed me that actual +observation upon that cable had been found to be +in accordance with his theoretic deduction.</p> + +<p>Three years subsequent to the publication +of these researches, that is to say on January 29, +1835, Faraday read before the Royal Society a +paper “On the influence by induction of an electric +current upon itself.” A shock and spark +of a peculiar character had been observed by a +young man named William Jenkin, who must +have been a youth of some scientific promise, but +who, as Faraday once informed me, was dissuaded +by his own father from having anything +to do with science. The investigation of the +fact noticed by Mr. Jenkin led Faraday to the +discovery of the <i>extra current</i>, or the current +<i>induced in the primary wire itself</i> at the moments +of making and breaking contact, the phenomena +of which he described and illustrated in the +beautiful and exhaustive paper referred to.</p> + +<p>Seven and thirty years have passed since the +discovery of magneto-electricity; but, if we +except the <i>extra current</i>, until quite recently +nothing of moment was added to the subject. +Faraday entertained the opinion that the discoverer +of a great law or principle had a right to +the “spoils”—this was his term—arising from its<span class='pagenum'><a name="Page_20" id="Page_20">[Pg 20]</a></span> +illustration; and guided by the principle he had +discovered, his wonderful mind, aided by his +wonderful ten fingers, overran in a single autumn +this vast domain, and hardly left behind him the +shred of a fact to be gathered by his successors.</p> + +<p>And here the question may arise in some minds, +What is the use of it all? The answer is, that if +man's intellectual nature thirsts for knowledge +then knowledge is useful because it satisfies this +thirst. If you demand practical ends, you must, +I think, expand your definition of the term practical, +and make it include all that elevates and +enlightens the intellect, as well as all that ministers +to the bodily health and comfort of men. +Still, if needed, an answer of another kind might +be given to the question “what is its use?” +As far as electricity has been applied for medical +purposes, it has been almost exclusively Faraday's +electricity. You have noticed those lines +of wire which cross the streets of London. It is +Faraday's currents that speed from place to +place through these wires. Approaching the +point of Dungeness, the mariner sees an unusually +brilliant light, and from the noble lighthouse +of La Hève the same light flashes across the sea. +These are Faraday's sparks exalted by suitable +machinery to sun-like splendour. At the present +moment the Board of Trade and the Brethren +of the Trinity House, as well as the Commissioners +of Northern Lights, are contemplating the introduction +of the Magneto-electric Light at +numerous points upon our coasts; and future<span class='pagenum'><a name="Page_21" id="Page_21">[Pg 21]</a></span> +generations will be able to refer to those guiding +stars in answer to the question, what has been +the practical use of the labours of Faraday? But +I would again emphatically say, that his work +needs no justification, and that if he had allowed +his vision to be disturbed by considerations regarding +the practical use of his discoveries, those +discoveries would never have been made by him. +“I have rather,” he writes in 1831, “been desirous +of discovering new facts and new relations +dependent on magneto-electric induction, than +of exalting the force of those already obtained; +being assured that the latter would find their +full development hereafter.”</p> + +<p>In 1817, when lecturing before a private society +in London on the element chlorine, Faraday +thus expresses himself with reference to this +question of utility. “Before leaving this subject, +I will point out the history of this substance +as an answer to those who are in the habit of +saying to every new fact, 'What is its use?' Dr. +Franklin says to such, 'What is the use of an infant?' +The answer of the experimentalist is, +'Endeavour to make it useful.' When Scheele +discovered this substance, it appeared to have no +use; it was in its infancy and useless state, but +having grown up to maturity, witness its powers, +and see what endeavours to make it useful have +done.”</p> + + + +<h2><a name="PROFESSOR_JOSEPH_HENRYS_INVENTION" id="PROFESSOR_JOSEPH_HENRYS_INVENTION"></a>PROFESSOR JOSEPH HENRY'S INVENTION<br /> +OF THE ELECTRIC TELEGRAPH</h2> +<span class="totoc"><a href="#toc">Top</a></span> +<p><span class='pagenum'><a name="Page_23" id="Page_23">[Pg 23]</a></span></p> + +<div class="noteb"><p>[In 1855 the Regents of the Smithsonian Institution, +Washington, D. C., at the instance of their secretary, Professor +Joseph Henry, took evidence with respect to his +claims as inventor of the electric telegraph. The essential +paragraphs of Professor Henry's statement are taken from +the Proceedings of the Board of Regents of the Smithsonian +Institution, Washington, 1857.]</p></div> + + +<p>There are several forms of the electric telegraph; +first, that in which frictional electricity +has been proposed to produce sparks and motion +of pith balls at a distance.</p> + +<p>Second, that in which galvanism has been employed +to produce signals by means of bubbles +of gas from the decomposition of water.</p> + +<p>Third, that in which electro-magnetism is the +motive power to produce motion at a distance; +and again, of the latter there are two kinds of +telegraphs, those in which the intelligence is indicated +by the motion of a magnetic needle, and +those in which sounds and permanent signs are +made by the attraction of an electro-magnet. +The latter is the class to which Mr. Morse's invention +belongs. The following is a brief exposition +of the several steps which led to this +form of the telegraph.</p> + +<p>The first essential fact which rendered the +electro-magnetic telegraph possible was discovered<span class='pagenum'><a name="Page_24" id="Page_24">[Pg 24]</a></span> +by Oersted, in the winter of 1819-'20. +It is illustrated by <a href="#Fig_1">figure 1</a>, in which the magnetic +needle is deflected by the action of a current +of galvanism transmitted through the wire +A B.</p> + +<a name="Fig_1" id="Fig_1"></a> +<div class="figcenter" style="width: 500px;"> +<img src="images/il040a.png" width="500" height="110" alt="Fig. 1" title="Fig. 1" /> +<span class="caption">Fig. 1</span> +</div> + +<p>The second fact of importance, discovered in +1820, by Arago and Davy, is illustrated in <a href="#Fig_2">Fig. 2</a>. +It consists in this, that while a current of galvanism +is passing through a copper wire A B, it +is magnetic, it attracts iron filings and not those +of copper or brass, and is capable of developing +magnetism in soft iron.</p> + +<a name="Fig_2" id="Fig_2"></a> +<div class="figcenter" style="width: 500px;"> +<img src="images/il040b.png" width="500" height="150" alt="Fig. 2" title="Fig. 2" /> +<span class="caption">Fig. 2</span> +</div> + +<p>The next important discovery, also made in +1820, by Ampère, was that two wires through +which galvanic currents are passing in the same +direction attract, and in the opposite direction,<span class='pagenum'><a name="Page_25" id="Page_25">[Pg 25]</a></span> +repel, each other. On this fact Ampère founded +his celebrated theory, that magnetism consists +merely in the attraction of electrical currents +revolving at right angles to the line joining the +two poles of the magnet. The magnetization of +a bar of steel or iron, according to this theory +consists in establishing within the metal by induction +a series of electrical currents, all revolving +in the same direction at right angles to the +axis or length of the bar.</p> + +<a name="Fig_3" id="Fig_3"></a> +<div class="figcenter" style="width: 500px;"> +<img src="images/il041.png" width="500" height="87" alt="Fig. 3" title="Fig. 3" /> +<span class="caption">Fig. 3</span> +</div> + +<p>It was this theory which led Arago, as he +states, to adopt the method of magnetizing +sewing needles and pieces of steel wire, shown in +<a href="#Fig_3">Fig. 3.</a> This method consists in transmitting +a current of electricity through a helix surrounding +the needle or wire to be magnetised. For +the purpose of insulation the needle was enclosed +in a glass tube, and the several turns of the helix +were at a distance from each other to insure the +passage of electricity through the whole length +of the wire, or, in other words, to prevent it from +seeking a shorter passage by cutting across from +one spire to another. The helix employed by +Arago obviously approximates the arrangement +required by the theory of Ampère, in order to +develop by induction the magnetism of the iron.<span class='pagenum'><a name="Page_26" id="Page_26">[Pg 26]</a></span> +By an attentive perusal of the original account +of the experiments of Arago, it will be seen that, +properly speaking, he made no electro-magnet, +as has been asserted by Morse and others; his +experiments were confined to the magnetism of +iron filings, to sewing needles and pieces of steel +wire of the diameter of a millimetre, or of about +the thickness of a small knitting needle.</p> + +<a name="Fig_4" id="Fig_4"></a> +<div class="figcenter" style="width: 500px;"> +<img src="images/il042.png" width="500" height="386" alt="Fig. 4" title="Fig. 4" /> +<span class="caption">Fig. 4</span> +</div> + +<p>Mr. Sturgeon, in 1825, made an important +step in advance of the experiments of Arago, and +produced what is properly known as the electro-magnet. +He bent a piece of iron <i>wire</i> into the +form of a horseshoe, covered it with varnish to +insulate it, and surrounded it with a helix, of +which the spires were at a distance. When a +current of galvanism was passed through the helix +from a small battery of a single cup the iron wire +became magnetic, and continued so during the +passage of the current. When the current was +interrupted the magnetism disappeared, and<span class='pagenum'><a name="Page_27" id="Page_27">[Pg 27]</a></span> +thus was produced the first temporary soft iron +magnet.</p> + +<p>The electro-magnet of Sturgeon is shown in +<a href="#Fig_4">Fig. 4.</a> By comparing <a href="#Fig_3">Figs. 3</a> and <a href="#Fig_4">4</a> it will be +seen that the helix employed by Sturgeon was +of the same kind as that used by Arago; instead +however, of a straight steel wire inclosed in a tube +of glass, the former employed a bent wire of soft +iron. The difference in +the arrangement at first +sight might appear to +be small, but the difference +in the results produced +was important, +since the temporary magnetism +developed in the +arrangement of Sturgeon +was sufficient to support +a weight of several +pounds, and an instrument was thus produced +of value in future research.</p> + +<a name="Fig_5" id="Fig_5"></a> +<div class="figright" style="width: 300px;"> +<img src="images/il043.png" width="300" height="293" alt="Fig. 5" title="Fig. 5" /> +<span class="caption">Fig. 5</span> +</div> + +<p>The next improvement was made by myself. +After reading an account of the galvanometer of +Schweigger, the idea occurred to me that a +much nearer approximation to the requirements +of the theory of Ampère could be attained by +insulating the conducting wire itself, instead of +the rod to be magnetized, and by covering the +whole surface of the iron with a series of coils +in close contact. This was effected by insulating +a long wire with silk thread, and winding this +around the rod of iron in close coils from one end<span class='pagenum'><a name="Page_28" id="Page_28">[Pg 28]</a></span> +to the other. The same principle was extended +by employing a still longer insulated wire, and +winding several strata of this over the first, care +being taken to insure the insulation between +each stratum by a covering of silk ribbon. By +this arrangement the rod was surrounded by a +compound helix formed of a long wire of many +coils, instead of a single helix of a few coils, +(<a href="#Fig_5">Fig. 5</a>).</p> + +<p>In the arrangement of Arago and Sturgeon the +several turns of wire were not precisely at right +angles to the axis of the rod, as they should be, +to produce the effect required by the theory, +but slightly oblique, and therefore each tended +to develop a separate magnetism not coincident +with the axis of the bar. But in winding the wire +over itself, the obliquity of the several turns +compensated each other, and the resultant action +was at right angles to the bar. The arrangement +then introduced by myself was superior to +those of Arago and Sturgeon, first in the greater +multiplicity of turns of wire, and second in the +better application of these turns to the development +of magnetism. The power of the instrument +with the same amount of galvanic force, +was by this arrangement several times increased.</p> + +<a name="Fig_6" id="Fig_6"></a> +<div class="figright" style="width: 284px;"> +<img src="images/il045.png" width="284" height="300" alt="Fig. 6" title="Fig. 6" /> +<span class="caption">Fig. 6</span> +</div> + +<p>The maximum effect, however, with this arrangement +and a single battery was not yet obtained. +After a certain length of wire had been +coiled upon the iron, the power diminished with +a further increase of the number of turns. This +was due to the increased resistance which the<span class='pagenum'><a name="Page_29" id="Page_29">[Pg 29]</a></span> +longer wire offered to the conduction of electricity. +Two methods of improvement therefore suggested +themselves. The first consisted, not in +increasing the length of the coil, but in using a +number of separate coils on the same piece of +iron. By this arrangement the resistance to the +conduction of the electricity was diminished and +a greater quantity made to circulate around the +iron from the same battery. +The second +method of producing a +similar result consisted +in increasing the number +of elements of the +battery, or, in other +words, the projectile +force of the electricity, +which enabled it to pass +through an increased +number of turns of wire, +and thus, by increasing the length of the wire, +to develop the maximum power of the iron.</p> + +<p>To test these principles on a larger scale, the +experimental magnet was constructed, which is +shown in <a href="#Fig_6">Fig. 6.</a> In this a number of compound +helices were placed on the same bar, their ends +left projecting, and so numbered that they could +be all united into one long helix, or variously +combined in sets of lesser length.</p> + +<p>From a series of experiments with this and +other magnets it was proved that, in order to +produce the greatest amount of magnetism from<span class='pagenum'><a name="Page_30" id="Page_30">[Pg 30]</a></span> +a battery of a single cup, a number of helices is +required; but when a compound battery is used, +then one long wire must be employed, making +many turns around the iron, the length of wire +and consequently the number of turns being +commensurate with the projectile power of the +battery.</p> + +<p>In describing the results of my experiments, +the terms <i>intensity</i> and <i>quantity</i> magnets were +introduced to avoid circumlocution, and were +intended to be used merely in a technical sense. +By the <i>intensity</i> magnet I designated a piece of +soft iron, so surrounded with wire that its magnetic +power could be called into operation by an +<i>intensity</i> battery, and by a <i>quantity</i> magnet, a +piece of iron so surrounded by a number of separate +coils, that its magnetism could be fully developed +by a <i>quantity</i> battery.</p> + +<p>I was the first to point out this connection of +the two kinds of the battery with the two forms +of the magnet, in my paper in <i>Silliman's Journal</i>, +January, 1831, and clearly to state that when +magnetism was to be developed by means of a +compound battery, one long coil was to be employed, +and when the maximum effect was to +be produced by a single battery, a number of +single strands were to be used.</p> + +<p>These steps in the advance of electro-magnetism, +though small, were such as to interest and +astonish the scientific world. With the same +battery used by Mr. Sturgeon, at least a hundred +times more magnetism was produced than could<span class='pagenum'><a name="Page_31" id="Page_31">[Pg 31]</a></span> +have been obtained by his experiment. The +developments were considered at the time of +much importance in a scientific point of view, +and they subsequently furnished the means by +which magneto-electricity, the phenomena of +dia-magnetism, and the magnetic effects on +polarized light were discovered. They gave rise +to the various forms of electro-magnetic machines +which have since exercised the ingenuity of inventors +in every part of the world, and were of +immediate applicability in the introduction of +the magnet to telegraphic purposes. Neither +the electro-magnet of Sturgeon nor any electro-magnet +ever made previous to my investigations +was applicable to transmitting power to a +distance.</p> + +<p>The principles I have developed were properly +appreciated by the scientific mind of Dr. Gale, +and applied by him to operate Mr. Morse's +machine at a distance.</p> + +<p>Previous to my investigations the means of +developing magnetism in soft iron were imperfectly +understood. The electro-magnet made +by Sturgeon, and copied by Dana, of New York, +was an imperfect quantity magnet, the feeble +power of which was developed by a single battery. +It was entirely inapplicable to a long circuit +with an intensity battery, and no person possessing +the requisite scientific knowledge, would +have attempted to use it in that connection after +reading my paper.</p> + +<p>In sending a message to a distance, two circuits<span class='pagenum'><a name="Page_32" id="Page_32">[Pg 32]</a></span> +are employed, the first a long circuit through +which the electricity is sent to the distant station +to bring into action the second, a short one, in +which is the local battery and magnet for working +the machine. In order to give projectile +force sufficient to send the power to a distance, +it is necessary to use an intensity battery in the +long circuit, and in connection with this, at +the distant station, a magnet surrounded with +many turns of one long wire must be employed +to receive and multiply the effect of the current +enfeebled by its transmission through the long +conductor. In the local or short circuit either +an intensity or a quantity magnet may be employed. +If the first be used, then with it a compound +battery will be required; and, therefore +on account of the increased resistance due to +the greater quantity of acid, a less amount of +work will be performed by a given amount of +material; and, consequently, though this arrangement +is practicable it is by no means economical. +In my original paper I state that the advantages +of a greater conducting power, from using several +wires in the quantity magnet, may, in a less degree, +be obtained by substituting for them one +large wire; but in this case, on account of the +greater obliquity of the spires and other causes, +the magnetic effect would be less. In accordance +with these principles, the receiving magnet, or +that which is introduced into the long circuit, +consists of a horseshoe magnet surrounded with +many hundred turns of a single long wire, and<span class='pagenum'><a name="Page_33" id="Page_33">[Pg 33]</a></span> +is operated with a battery of from twelve to +twenty-four elements or more, while in the local +circuit it is customary to employ a battery of one +or two elements with a much thicker wire and +fewer turns.</p> + +<p>It will, I think, be evident to the impartial +reader that these were improvements in the electro-magnet, +which first rendered it adequate to +the transmission of mechanical power to a distance; +and had I omitted all allusion to the telegraph +in my paper, the conscientious historian of +science would have awarded me some credit, +however small might have been the advance +which I made. Arago and Sturgeon, in the accounts +of their experiments, make no mention of +the telegraph, and yet their names always have +been and will be associated with the invention. +I briefly, however, called attention to the fact +of the applicability of my experiments to the +construction of the telegraph; but not being +familiar with the history of the attempts made +in regard to this invention, I called it “Barlow's +project,” while I ought to have stated that Mr. +Barlow's investigation merely tended to disprove +the possibility of a telegraph.</p> + +<p>I did not refer exclusively to the needle telegraph +when, in my paper, I stated that the <i>magnetic</i> +action of a current from a trough is at least +not sensibly diminished by passing through a long +wire. This is evident from the fact that the +immediate experiment from which this deduction +was made was by means of an electro-magnet<span class='pagenum'><a name="Page_34" id="Page_34">[Pg 34]</a></span> +and not by means of a needle galvanometer.</p> + +<a name="Fig_7" id="Fig_7"></a> +<div class="figcenter" style="width: 500px;"> +<img src="images/il050.png" width="500" height="384" alt="Fig. 7" title="Fig. 7" /> +<span class="caption">Fig. 7</span> +</div> + +<p>At the conclusion of the series of experiments +which I described in <i>Silliman's Journal</i>, there +were two applications of the electro-magnet in +my mind: one the production of a machine to be +moved by electro-magnetism, and the other the +transmission of or calling into action power at a +distance. The first was carried into execution +in the construction of the machine described in +<i>Silliman's Journal</i>, vol. xx, 1831, and for the purpose +of experimenting in regard to the second, I +arranged around one of the upper rooms in the +Albany Academy a wire of more than a mile in +length, through which I was enabled to make +signals by sounding a bell, (<a href="#Fig_7">Fig. 7.</a>) The mechanical +arrangement for effecting this object was +simply a steel bar, permanently magnetized, of +about ten inches in length, supported on a pivot,<span class='pagenum'><a name="Page_35" id="Page_35">[Pg 35]</a></span> +and placed with its north end between the two +arms of a horseshoe magnet. When the latter +was excited by the current, the end of the bar thus +placed was attracted by one arm of the horseshoe, +and repelled by the other, and was thus +caused to move in a horizontal plane and its further +extremity to strike a bell suitably adjusted.</p> + +<p>I also devised a method of breaking a circuit, +and thereby causing a large weight to fall. It was +intended to illustrate the practicability of calling +into action a great power at a distance capable +of producing mechanical effects; but as a description +of this was not printed, I do not place +it in the same category with the experiments of +which I published an account, or the facts which +could be immediately deduced from my papers in +<i>Silliman's Journal</i>.</p> + +<p>From a careful investigation of the history of +electro-magnetism in its connection with the +telegraph, the following facts may be established:</p> + +<p>1. Previous to my investigations the means of +developing magnetism in soft iron were imperfectly +understood, and the electro-magnet which +then existed was inapplicable to the transmission +of power to a distance.</p> + +<p>2. I was the first to prove by actual experiment +that, in order to develop magnetic power +at a distance, a galvanic battery of intensity +must be employed to project the current through +the long conductor, and that a magnet surrounded +by many turns of one long wire must be used to +receive this current.<span class='pagenum'><a name="Page_36" id="Page_36">[Pg 36]</a></span></p> + +<p>3. I was the first actually to magnetize a piece +of iron at a distance, and to call attention to the +fact of the applicability of my experiments to +the telegraph.</p> + +<p>4. I was the first to actually sound a bell at a +distance by means of the electro-magnet.</p> + +<p>5. The principles I had developed were applied +by Dr. Gale to render Morse's machine effective +at a distance.</p> + + + +<h2><a name="THE_FIRST_ATLANTIC_CABLES" id="THE_FIRST_ATLANTIC_CABLES"></a>THE FIRST ATLANTIC CABLES</h2> +<p><span class='pagenum'><a name="Page_37" id="Page_37">[Pg 37]</a></span></p> +<span class="totoc"><a href="#toc">Top</a></span> +<h3><span class="smcap">George Iles</span></h3> + +<div class="noteb"><p>[From “Flame, Electricity and the Camera,” copyright +Doubleday, Page & Co., New York.]</p></div> + + +<p>Electric telegraphy on land has put a vast +distance between itself and the mechanical signalling +of Chappé, just as the scope and availability +of the French invention are in high contrast +with the rude signal fires of the primitive savage. +As the first land telegraphs joined village to +village, and city to city, the crossing of water +came in as a minor incident; the wires were +readily committed to the bridges which spanned +streams of moderate width. Where a river or +inlet was unbridged, or a channel was too wide +for the roadway of the engineer, the question +arose, May we lay an electric wire under water? +With an ordinary land line, air serves as so good +a non-conductor and insulator that as a rule +cheap iron may be employed for the wire instead +of expensive copper. In the quest for non-conductors +suitable for immersion in rivers, channels, +and the sea, obstacles of a stubborn kind were +confronted. To overcome them demanded new +materials, more refined instruments, and a complete +revision of electrical philosophy.</p> + +<p>As far back as 1795, Francisco Salva had recommended +to the Academy of Sciences, Barcelona,<span class='pagenum'><a name="Page_38" id="Page_38">[Pg 38]</a></span> +the covering of subaqueous wires by resin, +which is both impenetrable by water and a non-conductor +of electricity. Insulators, indeed, of +one kind and another, were common enough, but +each of them was defective in some quality indispensable +for success. Neither glass nor +porcelain is flexible, and therefore to lay a continuous +line of one or the other was out of the +question. Resin and pitch were even more faulty, +because extremely brittle and friable. What of +such fibres as hemp or silk, if saturated with tar +or some other good non-conductor? For very +short distances under still water they served +fairly well, but any exposure to a rocky beach +with its chafing action, any rub by a passing +anchor, was fatal to them. What the copper +wire needed was a covering impervious to water, +unchangeable in composition by time, tough of +texture, and non-conducting in the highest degree. +Fortunately all these properties are united +in gutta-percha: they exist in nothing else known +to art. Gutta-percha is the hardened juice of a +large tree (<i>Isonandra gutta</i>) common in the +Malay Archipelago; it is tough and strong, easily +moulded when moderately heated. In comparison +with copper it is but one 60,000,000,000,000,000,000th +as conductive. As without gutta-percha +there could be no ocean telegraphy, it is +worth while recalling how it came within the +purview of the electrical engineer.</p> + +<p>In 1843 José d'Almeida, a Portuguese engineer, +presented to the Royal Asiatic Society,<span class='pagenum'><a name="Page_39" id="Page_39">[Pg 39]</a></span> +London, the first specimens of gutta-percha +brought to Europe. A few months later, Dr. +W. Montgomerie, a surgeon, gave other specimens +to the Society of Arts, of London, which +exhibited them; but it was four years before the +chief characteristic of the gum was recognized. +In 1847 Mr. S. T. Armstrong of New York, during +a visit to London, inspected a pound or two of +gutta-percha, and found it to be twice as good a +non-conductor as glass. The next year, through +his instrumentality, a cable covered with this +new insulator was laid between New York and +Jersey City; its success prompted Mr Armstrong +to suggest that a similarly protected cable be +submerged between America and Europe. +Eighteen years of untiring effort, impeded by +the errors inevitable to the pioneer, stood between +the proposal and its fulfilment. In 1848 +the Messrs. Siemens laid under water in the port +of Kiel a wire covered with seamless gutta-percha, +such as, beginning with 1847, they had +employed for subterranean conductors. This +particular wire was not used for telegraphy, but +formed part of a submarine-mine system. In +1849 Mr. C. V. Walker laid an experimental line +in the English Channel; he proved the possibility +of signalling for two miles through a wire covered +with gutta-percha, and so prepared the way for +a venture which joined the shores of France and +England.</p> + +<a name="Fig_58" id="Fig_58"></a> +<div class="figcenter" style="width: 500px;"> +<img src="images/il056.png" width="500" height="154" alt="Fig. 58.—Calais-Dover cable, 1851" title="Fig. 58.—Calais-Dover cable, 1851" /> +<span class="caption">Fig. 58.—Calais-Dover cable, 1851</span> +</div> + +<p>In 1850 a cable twenty-five miles in length +was laid from Dover to Calais, only to prove<span class='pagenum'><a name="Page_40" id="Page_40">[Pg 40]</a></span> +worthless from faulty insulation and the lack +of armour against dragging anchors and fretting +rocks. In 1851 the experiment was repeated +with success. The conductor now was not a +single wire of copper, but four wires, wound +spirally, so as to combine strength with flexibility; +these were covered with gutta-percha and surrounded +with tarred hemp. As a means of imparting +additional strength, ten iron wires were +wound round the hemp—a feature which has +been copied in every subsequent cable (<a href="#Fig_58">Fig. 58</a>). +The engineers were fast learning the rigorous +conditions of submarine telegraphy; in its essentials +the Dover-Calais line continues to be the +type of deep-sea cables to-day. The success of +the wire laid across the British Channel incited +other ventures of the kind. Many of them, +through careless construction or unskilful laying, +were utter failures. At last, in 1855, a submarine +line 171 miles in length gave excellent +service, as it united Varna with Constantinople; +this was the greatest length of satisfactory cable +until the submergence of an Atlantic line.<span class='pagenum'><a name="Page_41" id="Page_41">[Pg 41]</a></span></p> + +<p>In 1854 Cyrus W. Field of New York opened +a new chapter in electrical enterprise as he resolved +to lay a cable between Ireland and Newfoundland, +along the shortest line that joins +Europe to America. He chose Valentia and +Heart's Content, a little more than 1,600 miles +apart, as his termini, and at once began to enlist +the co-operation of his friends. Although an +unfaltering enthusiast when once his great idea +had possession of him, Mr. Field was a man of +strong common sense. From first to last he went +upon well-ascertained facts; when he failed he +did so simply because other facts, which he could +not possibly know, had to be disclosed by costly +experience. Messrs. Whitehouse and Bright, +electricians to his company, were instructed to +begin a preliminary series of experiments. They +united a continuous stretch of wires laid beneath +land and water for a distance of 2,000 miles, and +found that through this extraordinary circuit +they could transmit as many as four signals per +second. They inferred that an Atlantic cable +would offer but little more resistance, and would +therefore be electrically workable and commercially +lucrative.</p> + +<p>In 1857 a cable was forthwith manufactured, +divided in halves, and stowed in the holds of the +<i>Niagara</i> of the United States navy, and the +<i>Agamemnon</i> of the British fleet. The <i>Niagara</i> +sailed from Ireland; the sister ship proceeded to +Newfoundland, and was to meet her in mid-ocean. +When the <i>Niagara</i> had run out 335<span class='pagenum'><a name="Page_42" id="Page_42">[Pg 42]</a></span> +miles of her cable it snapped under a sudden increase +of strain at the paying-out machinery; +all attempts at recovery were unavailing, and the +work for that year was abandoned. The next +year it was resumed, a liberal supply of new +cable having been manufactured to replace the +lost section, and to meet any fresh emergency +that might arise. A new plan of voyages was +adopted: the vessels now sailed together to +mid-sea, uniting there both portions of the cable; +then one ship steamed off to Ireland, the other +to the Newfoundland coast. Both reached their +destinations on the same day, August 5, 1858, +and, feeble and irregular though it was, an electric +pulse for the first time now bore a message +from hemisphere to hemisphere. After 732 +despatches had passed through the wire it became +silent forever. In one of these despatches +from London, the War Office countermanded +the departure of two regiments about to leave +Canada for England, which saved an outlay of +about $250,000. This widely quoted fact demonstrated +with telling effect the value of cable +telegraphy.</p> + +<p>Now followed years of struggle which would +have dismayed any less resolute soul than Mr. +Field. The Civil War had broken out, with its +perils to the Union, its alarms and anxieties for +every American heart. But while battleships +and cruisers were patrolling the coast from +Maine to Florida, and regiments were marching +through Washington on their way to battle,<span class='pagenum'><a name="Page_43" id="Page_43">[Pg 43]</a></span> +there was no remission of effort on the part of the +great projector.</p> + +<p>Indeed, in the misunderstandings which grew +out of the war, and that at one time threatened +international conflict, he plainly saw how a cable +would have been a peace-maker. A single word +of explanation through its wire, and angry feelings +on both sides of the ocean would have been +allayed at the time of the <i>Trent</i> affair. In this +conviction he was confirmed by the English +press; the London <i>Times</i> said: “We nearly went +to war with America because we had no telegraph +across the Atlantic.” In 1859 the British government +had appointed a committee of eminent +engineers to inquire into the feasibility of an +Atlantic telegraph, with a view to ascertaining +what was wanting for success, and with the intention +of adding to its original aid in case the +enterprise were revived. In July, 1863, this +committee presented a report entirely favourable +in its terms, affirming “that a well-insulated +cable, properly protected, of suitable specific +gravity, made with care, tested under water +throughout its progress with the best-known +apparatus, and paid into the ocean with the most +improved machinery, possesses every prospect +of not only being successfully laid in the first +instance, but may reasonably be relied upon to +continue for many years in an efficient state for +the transmission of signals.”</p> + +<p>Taking his stand upon this endorsement, Mr. +Field now addressed himself to the task of raising<span class='pagenum'><a name="Page_44" id="Page_44">[Pg 44]</a></span> +the large sum needed to make and lay a new +cable which should be so much better than the +old ones as to reward its owners with triumph. +He found his English friends willing to venture +the capital required, and without further delay +the manufacture of a new cable was taken in +hand. In every detail the recommendations of +the Scientific Committee were carried out to the +letter, so that the cable of 1865 was incomparably +superior to that of 1858. First, the central +copper wire, which was the nerve along which +the lightning was to run, was nearly three times +larger than before. The old conductor was a +strand consisting of seven fine wires, six laid +around one, and weighed but 107 pounds to +the mile. The new was composed of the same +number of wires, but weighed 300 pounds to the +mile. It was made of the finest copper obtainable.</p> + +<p>To secure insulation, this conductor was first +embedded in Chatterton's compound, a preparation +impervious to water, and then covered with +four layers of gutta-percha, which were laid on +alternately with four thin layers of Chatterton's +compound. The old cable had but three coatings +of gutta-percha, with nothing between. +Its entire insulation weighed but 261 pounds +to the mile, while that of the new weighed 400 +pounds.<a name="FNanchor_1_1" id="FNanchor_1_1"></a><a href="#Footnote_1_1" class="fnanchor">[1]</a> The exterior wires, ten in number, +were of Bessemer steel, each separately wound<span class='pagenum'><a name="Page_45" id="Page_45">[Pg 45]</a></span> +in pitch-soaked hemp yarn, the shore ends +specially protected by thirty-six wires girdling +the whole. Here was a combination of the +tenacity of steel with much of the flexibility of +rope. The insulation of the copper was so +excellent as to exceed by a hundredfold that of +the core of 1858—which, faulty though it was, +had, nevertheless, sufficed for signals. So much +inconvenience and risk had been encountered +in dividing the task of cable-laying between two +ships that this time it was decided to charter a +single vessel, the <i>Great Eastern</i>, which, fortunately, +was large enough to accommodate the +cable in an unbroken length. Foilhommerum +Bay, about six miles from Valentia, was selected +as the new Irish terminus by the company. Although +the most anxious care was exercised in +every detail, yet, when 1,186 miles had been laid, +the cable parted in 11,000 feet of water, and +although thrice it was grappled and brought +toward the surface, thrice it slipped off the +grappling hooks and escaped to the ocean floor. +Mr. Field was obliged to return to England +and face as best he might the men whose capital +lay at the bottom of the sea—perchance as +worthless as so much Atlantic ooze. With +heroic persistence he argued that all difficulties +would yield to a renewed attack. There must +be redoubled precautions and vigilance never +for a moment relaxed. Everything that deep-sea +telegraphy has since accomplished was at +that moment daylight clear to his prophetic<span class='pagenum'><a name="Page_46" id="Page_46">[Pg 46]</a></span> +view. Never has there been a more signal example +of the power of enthusiasm to stir cold-blooded +men of business; never has there been a +more striking illustration of how much science +may depend for success upon the intelligence +and the courage of capital. Electricians might +have gone on perfecting exquisite apparatus for +ocean telegraphy, or indicated the weak points in +the comparatively rude machinery which made +and laid the cable, yet their exertions would +have been wasted if men of wealth had not responded +to Mr. Field's renewed appeal for help. +Thrice these men had invested largely, and thrice +disaster had pursued their ventures; nevertheless +they had faith surviving all misfortunes for +a fourth attempt.</p> + +<p>In 1866 a new company was organized, for two +objects: first, to recover the cable lost the previous +year and complete it to the American shore; +second, to lay another beside it in a parallel +course. The <i>Great Eastern</i> was again put in +commission, and remodelled in accordance with +the experience of her preceding voyage. This +time the exterior wires of the cable were of galvanized +iron, the better to resist corrosion. The +paying-out machinery was reconstructed and +greatly improved. On July 13, 1866, the huge +steamer began running out her cable twenty-five +miles north of the line struck out during the +expedition of 1865; she arrived without mishap +in Newfoundland on July 27, and electrical communication +was re-established between America<span class='pagenum'><a name="Page_47" id="Page_47">[Pg 47]</a></span> +and Europe. The steamer now returned to the +spot where she had lost the cable a few months +before; after eighteen days' search it was brought +to the deck in good order. Union was effected +with the cable stowed in the tanks below, and +the prow of the vessel was once more turned +to Newfoundland. On September 8th this second +cable was safely landed at Trinity Bay. Misfortunes +now were at an end; the courage of Mr. +Field knew victory at last; the highest honors +of two continents were showered upon him.</p> + +<div class="poem"><div class="stanza"> +<span class="i0">'Tis not the grapes of Canaan that repay,<br /></span> +<span class="i0">But the high faith that failed not by the way.<br /></span> +</div></div> + +<a name="Fig_59" id="Fig_59"></a> +<div class="figcenter" style="width: 500px;"> +<img src="images/il064.png" width="500" height="399" alt="Fig. 59.—Commercial cable, 1894" title="Fig. 59.—Commercial cable, 1894" /> +<span class="caption">Fig. 59.—Commercial cable, 1894</span> +</div> + +<p>What at first was as much a daring adventure +as a business enterprise has now taken its place +as a task no more out of the common than building +a steamship, or rearing a cantilever bridge. +Given its price, which will include too moderate +a profit to betray any expectation of failure, and +a responsible firm will contract to lay a cable +across the Pacific itself. In the Atlantic lines +the uniformly low temperature of the ocean +floor (about 4° C.), and the great pressure of the +superincumbent sea, co-operate in effecting an +enormous enhancement both in the insulation +and in the carrying capacity of the wire. As an +example of recent work in ocean telegraphy let +us glance at the cable laid in 1894, by the Commercial +Cable Company of New York. It unites +Cape Canso, on the northeastern coast of Nova +Scotia, to Waterville, on the southwestern coast +of Ireland. The central portion of this cable<span class='pagenum'><a name="Page_48" id="Page_48">[Pg 48]</a></span> +much resembles that of its predecessor in 1866. +Its exterior armour of steel wires is much more +elaborate. The first part of <a href="#Fig_59">Fig. 59</a> shows the +details of manufacture: the central copper core +is covered with gutta-percha, then with jute, +upon which the steel wires are spirally wound, +followed by a strong outer covering. For the +greatest depths at sea, type <i>A</i> is employed for a +total length of 1,420 miles; the diameter of this +part of the cable is seven-eighths of an inch. As +the water lessens in depth the sheathing increases +in size until the diameter of the cable +becomes one and one-sixteenth inches for 152 +miles, as type <i>B</i>. The cable now undergoes a +third enlargement, and then its fourth and last<span class='pagenum'><a name="Page_49" id="Page_49">[Pg 49]</a></span> +proportions are presented as it touches the shore, +for a distance of one and three-quarter miles, +where type <i>C</i> has a diameter of two and one-half +inches. The weights of material used in this +cable are: copper wire, 495 tons; gutta-percha, +315 tons; jute yarn, 575 tons; steel wire, 3,000 +tons; compound and tar, 1,075 tons; total, +5,460 tons. The telegraph-ship <i>Faraday</i>, specially +designed for cable-laying, accomplished +the work without mishap.</p> + +<p>Electrical science owes much to the Atlantic +cables, in particular to the first of them. At +the very beginning it banished the idea that +electricity as it passes through metallic conductors +has anything like its velocity through free +space. It was soon found, as Professor Mendenhall +says, “that it is no more correct to assign +a definite velocity to electricity than to a river. +As the rate of flow of a river is determined by the +character of its bed, its gradient, and other circumstances, +so the velocity of an electric current +is found to depend on the conditions under which +the flow takes place.”<a name="FNanchor_2_2" id="FNanchor_2_2"></a><a href="#Footnote_2_2" class="fnanchor">[2]</a> Mile for mile the original +Atlantic cable had twenty times the retarding +effect of a good aerial line; the best recent +cables reduce this figure by nearly one-half.</p> + +<p>In an extreme form, this slowing down reminds +us of the obstruction of light as it enters the atmosphere +of the earth, of the further impediment +which the rays encounter if they pass from<span class='pagenum'><a name="Page_50" id="Page_50">[Pg 50]</a></span> +the air into the sea. In the main the causes +which hinder a pulse committed to a cable are +two: induction, and the electrostatic capacity of +the wire, that is, the capacity of the wire to take +up a charge of its own, just as if it were the +metal of a Leyden jar.</p> + +<p>Let us first consider induction. As a current +takes its way through the copper core it induces +in its surroundings a second and opposing current. +For this the remedy is one too costly to +be applied. Were a cable manufactured in a +double line, as in the best telephonic circuits, +induction, with its retarding and quenching +effects, would be neutralized. Here the steel +wire armour which encircles the cable plays an +unwelcome part. Induction is always proportioned +to the conductivity of the mass in +which it appears; as steel is an excellent conductor, +the armour of an ocean cable, close as it is +to the copper core, has induced in it a current +much stronger, and therefore more retarding, +than if the steel wire were absent.</p> + +<p>A word now as to the second difficulty in working +beneath the sea—that due to the absorbing +power of the line itself. An Atlantic cable, like +any other extended conductor, is virtually a long, +cylindrical Leyden jar, the copper wire forming +the inner coat, and its surroundings the outer +coat. Before a signal can be received at the +distant terminus the wire must first be charged. +The effect is somewhat like transmitting a signal +through water which fills a rubber tube; first of<span class='pagenum'><a name="Page_51" id="Page_51">[Pg 51]</a></span> +all the tube is distended, and its compression, or +secondary effect, really transmits the impulse. +A remedy for this is a condenser formed of alternate +sheets of tin-foil and mica, <i>C</i>, connected +with the battery, <i>B</i>, so as to balance the electric +charge of the cable wire (<a href="#Fig_60">Fig. 60</a>). In the first +Atlantic line an impulse demanded one-seventh +of a second for its journey. This was reduced +when Mr. Whitehouse made the capital discovery +that the speed of a signal is increased +threefold when the wire is alternately connected +with the zinc and copper poles of the battery. +Sir William Thomson ascertained that these +successive pulses are most effective when of proportioned +lengths. He accordingly devised +an automatic transmitter which draws a duly +perforated slip of paper under a metallic spring +connected with the cable. To-day 250 to 300 +letters are sent per minute instead of fifteen, as +at first.</p> + +<a name="Fig_60" id="Fig_60"></a> +<div class="figcenter" style="width: 500px;"> +<img src="images/il067.png" width="500" height="411" alt="Fig. 60.—Condenser" title="Fig. 60.—Condenser" /> +<span class="caption">Fig. 60.—Condenser</span> +</div> + +<p>In many ways a deep-sea cable exaggerates in<span class='pagenum'><a name="Page_52" id="Page_52">[Pg 52]</a></span> +an instructive manner the phenomena of telegraphy +over long aerial lines. The two ends of a +cable may be in regions of widely diverse +electrical potential, or pressure, just as the readings +of the barometer at these two places may +differ much. If a copper wire were allowed to +offer itself as a gateless conductor it would +equalize these variations of potential with serious +injury to itself. Accordingly the rule is adopted +of working the cable not directly, as if it were a +land line, but indirectly through condensers. +As the throb sent through such apparatus is but +momentary, the cable is in no risk from the strong +currents which would course through it if it +were permitted to be an open channel.</p> + +<a name="Fig_61" id="Fig_61"></a> +<div class="figcenter" style="width: 500px;"> +<img src="images/il068.png" width="500" height="218" alt="Fig. 61.—Reflecting galvanometer +L, lamp; N, moving spot of light reflected from mirror" title="Fig. 61.—Reflecting galvanometer +L, lamp; N, moving spot of light reflected from mirror" /> +<span class="caption">Fig. 61.—Reflecting galvanometer<br /> +L, lamp; N, moving spot of light reflected from mirror</span> +</div> + +<p>A serious error in working the first cables was +in supposing that they required strong currents +as in land lines of considerable length. The +very reverse is the fact. Mr. Charles Bright, +in <i>Submarine Telegraphs</i>, says:<span class='pagenum'><a name="Page_53" id="Page_53">[Pg 53]</a></span></p> + +<p>“Mr. Latimer Clark had the conductor of the +1865 and 1866 lines joined together at the Newfoundland +end, thus forming an unbroken length +of 3,700 miles in circuit. He then placed some +sulphuric acid in a very small silver thimble, with +a fragment of zinc weighing a grain or two. By +this primitive agency he succeeded in conveying +signals through twice the breadth of the Atlantic +Ocean in little more than a second of time after +making contact. The deflections were not of a +dubious character, but full and strong, from which +it was manifest than an even smaller battery +would suffice to produce somewhat similar +effects.”</p> + +<a name="Fig_62" id="Fig_62"></a> +<div class="figcenter" style="width: 500px;"> +<img src="images/il069.png" width="500" height="491" alt="Fig. 62.—Siphon recorder" title="Fig. 62.—Siphon recorder" /> +<span class="caption">Fig. 62.—Siphon recorder</span> +</div> + +<p>At first in operating the Atlantic cable a mirror +galvanometer was employed as a receiver. The +principle of this receiver has often been illustrated<span class='pagenum'><a name="Page_54" id="Page_54">[Pg 54]</a></span> +by a mischievous boy as, with a slight and almost +imperceptible motion of his hand, he has +used a bit of looking-glass to dart a ray of reflected +sunlight across a wide street or a large +room. On the same plan, the extremely minute +motion of a galvanometer, as it receives the +successive pulsations of a message, is magnified +by a weightless lever of light so that the words +are easily read by an operator (<a href="#Fig_61">Fig. 61</a>). This +beautiful invention comes from the hands of Sir +William Thomson [now Lord Kelvin], who, +more than any other electrician, has made +ocean telegraphy an established success.</p> + +<a name="Fig_63" id="Fig_63"></a> +<div class="figcenter" style="width: 500px;"> +<img src="images/il070.png" width="500" height="93" alt="Fig. 63.—Siphon record. “Arrived yesterday”" title="Fig. 63.—Siphon record. “Arrived yesterday”" /> +<span class="caption">Fig. 63.—Siphon record. “Arrived yesterday”</span> +</div> + +<p>In another receiver, also of his design, the +siphon recorder, he began by taking advantage +of the fact, observed long before by Bose, that a +charge of electricity stimulates the flow of a +liquid. In its original form the ink-well into +which the siphon dipped was insulated and +charged to a high voltage by an influence-machine; +the ink, powerfully repelled, was spurted +from the siphon point to a moving strip of paper +beneath (<a href="#Fig_62">Fig. 62</a>). It was afterward found +better to use a delicate mechanical shaker which +throws out the ink in minute drops as the cable +current gently sways the siphon back and forth +(<a href="#Fig_63">Fig. 63</a>).<span class='pagenum'><a name="Page_55" id="Page_55">[Pg 55]</a></span></p> + +<p>Minute as the current is which suffices for +cable telegraphy, it is essential that the metallic +circuit be not only unbroken, but unimpaired +throughout. No part of his duty has more severely +taxed the resources of the electrician +than to discover the breaks and leaks in his ocean +cables. One of his methods is to pour electricity +as it were, into a broken wire, much as if it were +a narrow tube, and estimate the length of the +wire (and consequently the distance from shore +to the defect or break) by the quantity of current +required to fill it.</p> + + +<div class="footnotes"><h3>FOOTNOTES:</h3> + +<div class="footnote"><p><a name="Footnote_1_1" id="Footnote_1_1"></a><a href="#FNanchor_1_1"><span class="label">[1]</span></a> Henry M. Field, “History of the Atlantic Telegraph.” +New York: Scribner, 1866.</p></div> + +<div class="footnote"><p><a name="Footnote_2_2" id="Footnote_2_2"></a><a href="#FNanchor_2_2"><span class="label">[2]</span></a> “A Century of Electricity.” Boston, Houghton, +Mifflin & Co., 1887.</p></div> +</div> + + + +<h2><a name="BELLS_TELEPHONIC_RESEARCHES" id="BELLS_TELEPHONIC_RESEARCHES"></a>BELL'S TELEPHONIC RESEARCHES</h2> +<p><span class='pagenum'><a name="Page_57" id="Page_57">[Pg 57]</a></span></p> +<span class="totoc"><a href="#toc">Top</a></span> +<div class="noteb"><p>[From “Bell's Electric Speaking Telephones,” by George +B. Prescott, copyright by D Appleton & Co., New York, 1884]</p></div> + + +<p>In a lecture delivered before the Society of +Telegraph Engineers, in London, October 31, +1877, Prof. A. G. Bell gave a history of his researches +in telephony, together with the experiments +that he was led to undertake in his endeavours +to produce a practical system of multiple +telegraphy, and to realize also the transmission +of articulate speech. After the usual +introduction, Professor Bell said in part:</p> + +<p>It is to-night my pleasure, as well as duty, +to give you some account of the telephonic researches +in which I have been so long engaged. +Many years ago my attention was directed to +the mechanism of speech by my father, Alexander +Melville Bell, of Edinburgh, who has made a +life-long study of the subject. Many of those +present may recollect the invention by my father +of a means of representing, in a wonderfully +accurate manner, the positions of the vocal +organs in forming sounds. Together we carried +on quite a number of experiments, seeking to +discover the correct mechanism of English and +foreign elements of speech, and I remember +especially an investigation in which we were<span class='pagenum'><a name="Page_58" id="Page_58">[Pg 58]</a></span> +engaged concerning the musical relations of +vowel sounds. When vocal sounds are whispered, +each vowel seems to possess a particular +pitch of its own, and by whispering certain vowels +in succession a musical scale can be distinctly +perceived. Our aim was to determine the +natural pitch of each vowel; but unexpected +difficulties made their appearance, for many of +the vowels seemed to possess a double pitch—one +due, probably, to the resonance of the air in +the mouth, and the other to the resonance of the +air contained in the cavity behind the tongue, +comprehending the pharynx and larynx.</p> + +<p>I hit upon an expedient for determining the +pitch, which, at that time, I thought to be original +with myself. It consisted in vibrating a tuning +fork in front of the mouth while the positions of +the vocal organs for the various vowels were +silently taken. It was found that each vowel +position caused the reinforcement of some particular +fork or forks.</p> + +<p>I wrote an account of these researches to Mr. +Alex. J. Ellis, of London. In reply, he informed +me that the experiments related had already been +performed by Helmholtz, and in a much more +perfect manner than I had done. Indeed, he +said that Helmholtz had not only analyzed the +vowel sounds into their constituent musical elements, +but had actually performed the synthesis +of them.</p> + +<p>He had succeeded in producing, artificially, +certain of the vowel sounds by causing tuning<span class='pagenum'><a name="Page_59" id="Page_59">[Pg 59]</a></span> +forks of different pitch to vibrate simultaneously +by means of an electric current. Mr. Ellis was +kind enough to grant me an interview for the +purpose of explaining the apparatus employed +by Helmholtz in producing these extraordinary +effects, and I spent the greater part of a delightful +day with him in investigating the subject. +At that time, however, I was too slightly acquainted +with the laws of electricity fully to +understand the explanations given; but the interview +had the effect of arousing my interest in +the subjects of sound and electricity, and I did +not rest until I had obtained possession of a copy +of Helmholtz's great work “The Theory of Tone,” +and had attempted, in a crude and imperfect +manner, it is true, to reproduce his results. While +reflecting upon the possibilities of the production +of sound by electrical means, it struck me that +the principle of vibrating a tuning fork by the +intermittent attraction of an electro-magnet +might be applied to the electrical production of +music.</p> + +<p>I imagined to myself a series of tuning forks +of different pitches, arranged to vibrate automatically +in the manner shown by Helmholtz—each +fork interrupting, at every vibration, a +voltaic current—and the thought occurred, Why +should not the depression of a key like that of a +piano direct the interrupted current from any +one of these forks, through a telegraph wire, to +a series of electro-magnets operating the strings +of a piano or other musical instrument, in which<span class='pagenum'><a name="Page_60" id="Page_60">[Pg 60]</a></span> +case a person might play the tuning fork piano +in one place and the music be audible from the +electro-magnetic piano in a distant city.</p> + +<p>The more I reflected upon this arrangement +the more feasible did it seem to me; indeed, I +saw no reason why the depression of a number +of keys at the tuning fork end of the circuit should +not be followed by the audible production of a +full chord from the piano in the distant city, each +tuning fork affecting at the receiving end that +string of the piano with which it was in unison. +At this time the interest which I felt in electricity +led me to study the various systems of telegraphy +in use in this country and in America. I was +much struck with the simplicity of the Morse +alphabet, and with the fact that it could be +read by sound. Instead of having the dots and +dashes recorded on paper, the operators were +in the habit of observing the duration of the +click of the instruments, and in this way were +enabled to distinguish by ear the various signals.</p> + +<p>It struck me that in a similar manner the duration +of a musical note might be made to represent +the dot or dash of the telegraph code, so that +a person might operate one of the keys of the +tuning fork piano referred to above, and the duration +of the sound proceeding from the corresponding +string of the distant piano be observed +by an operator stationed there. It seemed to +me that in this way a number of distinct telegraph +messages might be sent simultaneously +from the tuning fork piano to the other end of the<span class='pagenum'><a name="Page_61" id="Page_61">[Pg 61]</a></span> +circuit by operators, each manipulating a different +key of the instrument. These messages would +be read by operators stationed at the distant +piano, each receiving operator listening for signals +for a certain definite pitch, and ignoring all +others. In this way could be accomplished the +simultaneous transmission of a number of telegraphic +messages along a single wire, the number +being limited only by the delicacy of the listener's +ear. The idea of increasing the carrying power +of a telegraph wire in this way took complete +possession of my mind, and it was this practical +end that I had in view when I commenced my +researches in electric telephony.</p> + +<a name="il077" id="il077"></a> +<div class="figcenter" style="width: 500px;"> +<img src="images/il077.png" width="500" height="141" alt="Fig. 1" title="Fig. 1" /> +<span class="caption">Fig. 1</span> +</div> + +<p>In the progress of science it is universally found +that complexity leads to simplicity, and in narrating +the history of scientific research it is often +advisable to begin at the end.</p> + +<p>In glancing back over my own researches, I +find it necessary to designate, by distinct names, +a variety of electrical currents by means of which +sounds can be produced, and I shall direct your +attention to several distinct species of what may<span class='pagenum'><a name="Page_62" id="Page_62">[Pg 62]</a></span> +be termed telephonic currents of electricity. In +order that the peculiarities of these currents may +be clearly understood, I shall project upon the +screen a graphical illustration of the different +varieties.</p> + +<p>The graphical method of representing electrical +currents shown in <a href="#il077">Fig. 1</a> is the best means I have +been able to devise of studying, in an accurate +manner, the effects produced by various forms +of telephonic apparatus, and it has led me to the +conception of that peculiar species of telephonic +current, here designated as <i>undulatory</i>, which has +rendered feasible the artificial production of +articulate speech by electrical means.</p> + +<p>A horizontal line (<i>g g´</i>) is taken as the zero of +current, and impulses of positive electricity are +represented above the zero line, and negative +impulses below it, or <i>vice versa</i>.</p> + +<p>The vertical thickness of any electrical impulse +(<i>b</i> or <i>d</i>), measured from the zero line, indicates +the intensity of the electrical current at +the point observed; and the horizontal extension +of the electric line (<i>b</i> or <i>d</i>) indicates the duration +of the impulse.</p> + +<p>Nine varieties of telephonic currents may be +distinguished, but it will only be necessary to +show you six of these. The three primary varieties +designated as intermittent, pulsatory and +undulatory, are represented in lines 1, 2 and 3.</p> + +<p>Sub-varieties of these can be distinguished as +direct or reversed currents, according as the +electrical impulses are all of one kind or are alternately<span class='pagenum'><a name="Page_63" id="Page_63">[Pg 63]</a></span> +positive and negative. Direct currents +may still further be distinguished as positive +or negative, according as the impulses are of one +kind or of the other.</p> + +<p>An intermittent current is characterized by +the alternate presence and absence of electricity +upon the circuit.</p> + +<p>A pulsatory current results from sudden or +instantaneous changes in the intensity of a continuous +current; and</p> + +<p>An undulatory current is a current of electricity, +the intensity of which varies in a manner proportional +to the velocity of the motion of a particle +of air during the production of a sound: +thus the curve representing graphically the undulatory +current for a simple musical note is the +curve expressive of a simple pendulous vibration—that +is, a sinusoidal curve.</p> + +<p>And here I may remark, that, although the +conception of the undulatory current of electricity +is entirely original with myself, methods of +producing sound by means of intermittent and +pulsatory currents have long been known. For +instance, it was long since discovered that an +electro-magnet gives forth a decided sound when +it is suddenly magnetized or demagnetized. +When the circuit upon which it is placed is rapidly +made and broken, a succession of explosive +noises proceeds from the magnet. These sounds +produce upon the ear the effect of a musical note +when the current is interrupted a sufficient number +of times per second....<span class='pagenum'><a name="Page_64" id="Page_64">[Pg 64]</a></span></p> + +<a name="il080" id="il080"></a> +<div class="figcenter" style="width: 500px;"> +<img src="images/il080.png" width="500" height="370" alt="Fig. 2" title="Fig. 2" /> +<span class="caption">Fig. 2</span> +</div> + +<p>For several years my attention was almost +exclusively directed to the production of an instrument +for making and breaking a voltaic +circuit with extreme rapidity, to take the place +of the transmitting tuning fork used in Helmholtz's +researches. Without going into details, +I shall merely say that the great defects of this +plan of multiple telegraphy were found to consist, +first, in the fact that the receiving operators +were required to possess a good musical ear +in order to discriminate the signals; and secondly, +that the signals could only pass in one direction +along the line (so that two wires would be necessary +in order to complete communication in both +directions). The first objection was got over +by employing the device which I term a “vibratory +circuit breaker,” whereby musical signals +can be automatically recorded....<span class='pagenum'><a name="Page_65" id="Page_65">[Pg 65]</a></span></p> + +<p>I have formerly stated that Helmholtz was enabled +to produce vowel sounds artificially by combining +musical tones of different pitches and intensities. +His apparatus is shown in <a href="#il080">Fig. 2.</a> +Tuning forks of different pitch are placed between +the poles of electro-magnets (<i>a1</i>, <i>a2</i>, &c.), +and are kept in continuous vibration by the action +of an intermittent current from the fork <i>b</i>. Resonators, +1, 2, 3, etc., are arranged so as to reinforce +the sounds in a greater or less degree, according +as the exterior orifices are enlarged or +contracted.</p> + +<a name="il082" id="il082"></a> +<div class="figcenter" style="width: 500px;"> +<img src="images/il082.png" width="500" height="261" alt="Fig. 3" title="Fig. 3" /> +<span class="caption">Fig. 3</span> +</div> + +<p>Thus it will be seen that upon Helmholtz's plan +the tuning forks themselves produce tones of +uniform intensity, the loudness being varied +by an external reinforcement; but it struck me +that the same results would be obtained, and in +a much more perfect manner, by causing the +tuning forks themselves to vibrate with different +degrees of amplitude. I therefore devised the +apparatus shown in <a href="#il082">Fig. 3</a>, which was my first +form of articulating telephone. In this figure a +harp of steel rods is employed, attached to the +poles of a permanent magnet, N. S. When any +one of the rods is thrown into vibration an undulatory +current is produced in the coils of the +electro-magnet E, and the electro-magnet E´ attracts +the rods of the harp H´ with a varying +force, throwing into vibration that rod which is +in unison with that vibrating at the other end +of the circuit. Not only so, but the amplitude of +vibration in the one will determine the amplitude<span class='pagenum'><a name="Page_66" id="Page_66">[Pg 66]</a></span> +of vibration in the other, for the intensity of the +induced current is determined by the amplitude +of the inducing vibration, and the amplitude of +the vibration at the receiving end depends upon +the intensity of the attractive impulses. When +we sing into a piano, certain of the strings of the +instrument are set in vibration sympathetically +by the action of the voice with different degrees +of amplitude, and a sound, which is an approximation +to the vowel uttered, is produced from the +piano. Theory shows that, had the piano a very +much larger number of strings to the octave, the +vowel sounds would be perfectly reproduced. +My idea of the action of the apparatus, shown +in <a href="#il082">Fig. 3</a>, was this: Utter a sound in the neighbourhood +of the harp H, and certain of the rods +would be thrown into vibration with different +amplitudes. At the other end of the circuit the +corresponding rods of the harp H would vibrate +with their proper relations of force, and the<span class='pagenum'><a name="Page_67" id="Page_67">[Pg 67]</a></span> +<i>timbre</i> [characteristic quality] of the sound would +be reproduced. The expense of constructing such +an apparatus as that shown in <a href="#il082">figure 3</a> deterred +me from making the attempt, and I sought to +simplify the apparatus before venturing to have +it made.</p> + +<a name="il083" id="il083"></a> +<div class="figcenter" style="width: 500px;"> +<img src="images/il083.png" width="500" height="268" alt="Fig. 4" title="Fig. 4" /> +<span class="caption">Fig. 4</span> +</div> + +<p>I have before alluded to the invention by my +father of a system of physiological symbols for +representing the action of the vocal organs, and +I had been invited by the Boston Board of Education +to conduct a series of experiments with +the system in the Boston school for the deaf and +dumb. It is well known that deaf mutes are +dumb merely because they are deaf, and that +there is no defect in their vocal organs to incapacitate +them from utterance. Hence it was +thought that my father's system of pictorial +symbols, popularly known as visible speech,<span class='pagenum'><a name="Page_68" id="Page_68">[Pg 68]</a></span> +might prove a means whereby we could teach +the deaf and dumb to use their vocal organs and +to speak. The great success of these experiments +urged upon me the advisability of devising +method of exhibiting the vibrations of sound +optically, for use in teaching the deaf and dumb. +For some time I carried on experiments with the +manometric capsule of Köenig and with the +phonautograph of Léon Scott. The scientific +apparatus in the Institute of Technology in +Boston was freely placed at my disposal for +these experiments, and it happened that at that +time a student of the Institute of Technology, +Mr. Maurey, had invented an improvement upon +the phonautograph. He had succeeded in vibrating +by the voice a stylus of wood about a foot in +length, which was attached to the membrane of +the phonautograph, and in this way he had +been enabled to obtain enlarged tracings upon a +plane surface of smoked glass. With this apparatus +I succeeded in producing very beautiful +tracings of the vibrations of the air for vowel +sounds. Some of these tracings are shown in +<a href="#il083">Fig. 4</a>. I was much struck with this improved +form of apparatus, and it occurred to me that +there was a remarkable likeness between the +manner in which this piece of wood was vibrated +by the membrane of the phonautograph and the +manner in which the <i>ossiculo</i> [small bones] of +the human ear were moved by the tympanic +membrane. I determined therefore, to construct +a phonautograph modelled still more<span class='pagenum'><a name="Page_69" id="Page_69">[Pg 69]</a></span> +closely upon the mechanism of the human ear, +and for this purpose I sought the assistance of a +distinguished aurist in Boston, Dr. Clarence J. +Blake.</p> +<a name="il085" id="il085"></a> +<div class="figcenter" style="width: 382px;"> +<img src="images/il085.png" width="382" height="500" alt="Fig. 5" title="Fig. 5" /> +<span class="caption">Fig. 5</span> +</div> +<p class="noindent">He suggested the use of the human ear +itself as a phonautograph, instead of making an<span class='pagenum'><a name="Page_70" id="Page_70">[Pg 70]</a></span> +artificial imitation of it. The idea was novel +and struck me accordingly, and I requested my +friend to prepare a specimen for me, which he +did. The apparatus, as finally constructed, is +shown in <a href="#il085">Fig. 5</a>. The <i>stapes</i> [inmost of the +three auditory ossicles] was removed and a +pointed piece of hay about an inch in length +was attached to the end of the incus [the middle +of the three auditory ossicles].</p> +<a name="il086" id="il086"></a> +<div class="figcenter" style="width: 500px;"> +<img src="images/il086.png" width="500" height="177" alt="Fig. 6" title="Fig. 6" /> +<span class="caption">Fig. 6</span> +</div> +<p class="noindent">Upon moistening +the membrana tympani [membrane of the +ear drum] and the ossiculæ with a mixture of +glycerine and water the necessary mobility of +the parts was obtained, and upon singing into the +external artificial ear the piece of hay was thrown +into vibration, and tracings were obtained upon +a plane surface of smoked glass passed rapidly +underneath. While engaged in these experiments +I was struck with the remarkable disproportion +in weight between the membrane and +the bones that were vibrated by it. It occurred +to me that if a membrane as thin as tissue paper +could control the vibration of bones that were, +compared to it, of immense size and weight, why<span class='pagenum'><a name="Page_71" id="Page_71">[Pg 71]</a></span> +should not a larger and thicker membrane be +able to vibrate a piece of iron in front of an +electro-magnet, in which case the complication +of steel rods shown in my first form of telephone, +<a href="#il082">Fig. 3</a>, could be done away with, and a simple +piece of iron attached to a membrane be placed +at either end of the telegraphic circuit.</p> + +<a name="il088" id="il088"></a> +<div class="figcenter" style="width: 500px;"> +<img src="images/il088.png" width="500" height="198" alt="Fig. 7" title="Fig. 7" /> +<span class="caption">Fig. 7</span> +</div> + +<p><a href="#il086">Figure 6</a> shows the form of apparatus that I +was then employing for producing undulatory +currents of electricity for the purpose of multiple +telegraphy. A steel reed, A, was clamped firmly +by one extremity to the uncovered leg <i>h</i> of an +electro-magnet E, and the free end of the reed +projected above the covered leg. When the +reed A was vibrated in any mechanical way the +battery current was thrown into waves, and +electrical undulations traversed the circuit +B E W E´, throwing into vibration the corresponding +reed A´ at the other end of the circuit. +I immediately proceeded to put my new idea to +the test of practical experiment, and for this +purpose I attached the reed A (<a href="#il088">Fig. 7</a>) loosely +by one extremity to the uncovered pole <i>h</i> of the +magnet, and fastened the other extremity to the +centre of a stretched membrane of goldbeaters' +skin <i>n</i>. I presumed that upon speaking in the +neighbourhood of the membrane <i>n</i> it would be +thrown into vibration and cause the steel reed A +to move in a similar manner, occasioning undulations +in the electrical current that would correspond +to the changes in the density of the air +during the production of the sound; and I further<span class='pagenum'><a name="Page_72" id="Page_72">[Pg 72]</a></span> +thought that the change of the density of the +current at the receiving end would cause the +magnet there to attract the reed A´ in such a +manner that it should copy the motion of the +reed A, in which case its movements would occasion +a sound from the membrane <i>n´</i> similar +in <i>timbre</i> to that which had occasioned the original +vibration.</p> + +<a name="il089" id="il089"></a> +<div class="figcenter" style="width: 500px;"> +<img src="images/il089.png" width="500" height="244" alt="Fig. 8" title="Fig. 8" /> +<span class="caption">Fig. 8</span> +</div> + +<p>The results, however, were unsatisfactory and +discouraging. My friend, Mr. Thomas A. Watson, +who assisted me in this first experiment, +declared that he heard a faint sound proceed +from the telephone at his end of the circuit, but I +was unable to verify his assertion. After many +experiments, attended by the same only partially +successful results, I determined to reduce the +size and weight of the spring as much as possible. +For this purpose I glued a piece of clock spring +about the size and shape of my thumb nail, +firmly to the centre of the diaphragm, and had +a similar instrument at the other end (<a href="#il089">Fig. 8</a>); +we were then enabled to obtain distinctly audible<span class='pagenum'><a name="Page_73" id="Page_73">[Pg 73]</a></span> +effects. I remember an experiment made +with this telephone, which at the time gave +me great satisfaction and delight. One of the +telephones was placed in my lecture room in the +Boston University, and the other in the basement +of the adjoining building. One of my +students repaired to the distant telephone to +observe the effects of articulate speech, while I +uttered the sentence, “Do you understand what I +say?” into the telephone placed in the lecture +hall. To my delight an answer was returned +through the instrument itself, articulate sounds +proceeded from the steel spring attached to the +membrane, and I heard the sentence, “Yes, I +understand you perfectly.” It is a mistake, +however, to suppose that the articulation was by +any means perfect, and expectancy no doubt had +a great deal to do with my recognition of the +sentence; still, the articulation was there, and I +recognized the fact that the indistinctness was<span class='pagenum'><a name="Page_74" id="Page_74">[Pg 74]</a></span> +entirely due to the imperfection of the instrument. +I will not trouble you by detailing the +various stages through which the apparatus +passed, but shall merely say that after a time I +produced the form of instrument shown in <a href="#il090">Fig. 9</a>, +which served very well as a receiving telephone. +In this condition my invention was, in 1876, +exhibited at the Centennial Exhibition in Philadelphia. +The telephone shown in <a href="#il089">Fig. 8</a> was +used as a transmitting instrument, and that in +<a href="#il090">Fig. 9</a> as a receiver, so that vocal communication +was only established in one direction....</p> + +<a name="il090" id="il090"></a> +<div class="figcenter" style="width: 500px;"> +<img src="images/il090.png" width="500" height="368" alt="Fig. 9" title="Fig. 9" /> +<span class="caption">Fig. 9</span> +</div> + +<p>The articulation produced from the instrument +shown in <a href="#il090">Fig. 9</a> was remarkably distinct, +but its great defect consisted in the fact that it +could not be used as a transmitting instrument, +and thus two telephones were required at each +station, one for transmitting and one for receiving +spoken messages.</p> + +<a name="il091" id="il091"></a> +<div class="figcenter" style="width: 500px;"> +<img src="images/il091.png" width="500" height="317" alt="Fig. 10" title="Fig. 10" /> +<span class="caption">Fig. 10</span> +</div> + +<p>It was determined to vary the construction of<span class='pagenum'><a name="Page_75" id="Page_75">[Pg 75]</a></span> +the telephone shown in <a href="#il089">Fig. 8</a>, and I sought, by +changing the size and tension of the membrane, +the diameter and thickness of the steel spring, +the size and power of the magnet, and the coils of +insulated wire around their poles, to discover +empirically the exact effect of each element of +the combination, and thus to deduce a more +perfect form of apparatus. It was found that a +marked increase in the loudness of the sounds +resulted from shortening the length of the coils +of wire, and by enlarging the iron diaphragm +which was glued to the membrane. In the latter +case, also, the distinctness of the articulation was +improved. Finally, the membrane of goldbeaters' +skin was discarded entirely, and a simple +iron plate was used instead, and at once intelligible +articulation was obtained. The new form +of instrument is that shown in <a href="#il091">Fig. 10</a>, and, as +had been long anticipated, it was proved that the +only use of the battery was to magnetize the iron<span class='pagenum'><a name="Page_76" id="Page_76">[Pg 76]</a></span> +core, for the effects were equally audible when the +battery was omitted and a rod of magnetized +steel substituted for the iron core of the magnet.</p> + +<a name="il092" id="il092"></a> +<div class="figcenter" style="width: 500px;"> +<img src="images/il092.png" width="500" height="318" alt="Fig. 11" title="Fig. 11" /> +<span class="caption">Fig. 11</span> +</div> + +<p>It was my original intention, as shown in <a href="#il082">Fig. 3</a>, +and it was always claimed by me, that the final +form of telephone would be operated by permanent +magnets in place of batteries, and numerous +experiments had been carried on by Mr. +Watson and myself privately for the purpose of +producing this effect.</p> + +<p>At the time the instruments were first exhibited +in public the results obtained with permanent +magnets were not nearly so striking as when a +voltaic battery was employed, wherefore we +thought it best to exhibit only the latter form of +instrument.</p> + +<p>The interest excited by the first published accounts +of the operation of the telephone led many +persons to investigate the subject, and I doubt +not that numbers of experimenters have independently<span class='pagenum'><a name="Page_77" id="Page_77">[Pg 77]</a></span> +discovered that permanent magnets +might be employed instead of voltaic batteries. +Indeed, one gentleman, Professor Dolbear, of +Tufts College, not only claims to have discovered +the magneto-electric telephone, but, I understand, +charges me with having obtained the idea +from him through the medium of a mutual friend.</p> + +<p>A still more powerful form of apparatus was +constructed by using a powerful compound horseshoe +magnet in place of the straight rod which +had been previously used (<a href="#il092">see Fig. 11</a>). Indeed, +the sounds produced by means of this instrument +were of sufficient loudness to be faintly +audible to a large audience, and in this condition +the instrument was exhibited in the Essex Institute, +in Salem, Massachusetts, on the 12th +of February, 1877, on which occasion a short +speech shouted into a similar telephone in Boston +sixteen miles away, was heard by the audience in +Salem. The tones of the speaker's voice were +distinctly audible to an audience of six hundred +people, but the articulation was only distinct at +a distance of about six feet. On the same occasion, +also, a report of the lecture was transmitted +by word of mouth from Salem to Boston, +and published in the papers the next morning.</p> + +<p>From the form of telephone shown in <a href="#il091">Fig. 10</a> +to the present form of the instrument (<a href="#il096">Fig. 12</a>) +is but a step. It is, in fact, the arrangement of +<a href="#il091">Fig. 10</a> in a portable form, the magnet F. H. being +placed inside the handle and a more convenient +form of mouthpiece provided....<span class='pagenum'><a name="Page_78" id="Page_78">[Pg 78]</a></span></p> + +<p>It was always my belief that a certain ratio +would be found between the several parts of a telephone, +and that the size of the instrument was +immaterial; but Professor Peirce was the first to +demonstrate the extreme smallness of the magnets +which might be employed. And here, in order +to show the parallel lines in which we were working, +I may mention the fact that two or three +days after I had constructed a telephone of the +portable form (<a href="#il096">Fig. 12</a>), containing the magnet +inside the handle, Dr. Channing was kind enough +to send me a pair of telephones of a similar +pattern, which had been invented by experimenters +at Providence. The convenient form +of the mouthpiece shown in <a href="#il096">Fig. 12</a>, now adopted +by me, was invented solely by my friend, Professor +Peirce. I must also express my obligations +to my friend and associate, Mr. Thomas A. +Watson, of Salem, Massachusetts, who has for +two years past given me his personal assistance +in carrying on my researches.</p> + +<p>In pursuing my investigations I have ever had +one end in view—the practical improvement of +electric telegraphy—but I have come across +many facts which, while having no direct bearing +upon the subject of telegraphy, may yet possess +an interest for you.</p> + +<p>For instance, I have found that a musical tone +proceeds from a piece of plumbago or retort +carbon when an intermittent current of electricity +is passed through it, and I have observed the +most curious audible effects produced by the<span class='pagenum'><a name="Page_79" id="Page_79">[Pg 79]</a></span> +passage of reversed intermittent currents through +the human body. A breaker was placed in +circuit with the primary wires of an induction +coil, and the fine wires were connected with two +strips of brass. One of these strips was held +closely against the ear, and a loud sound proceeded +from it whenever the other slip was +touched with the other hand. The strips of +brass were next held one in each hand. The +induced currents occasioned a muscular tremor +in the fingers. Upon placing my forefinger to my +ear a loud crackling noise was audible, seemingly +proceeding from the finger itself. A friend who +was present placed my finger to his ear, but heard +nothing. I requested him to hold the strips +himself. He was then distinctly conscious of a +noise (which I was unable to perceive) proceeding +from his finger. In this case a portion of the +induced current passed through the head of the +observer when he placed his ear against his own +finger, and it is possible that the sound was occasioned +by a vibration of the surfaces of the ear +and finger in contact.</p> + +<p>When two persons receive a shock from a +Ruhmkorff's coil by clasping hands, each taking +hold of one wire of the coil with the free hand, a +sound proceeds from the clasped hands. The +effect is not produced when the hands are moist. +When either of the two touches the body of the +other a loud sound comes from the parts in contact. +When the arm of one is placed against the +arm of the other, the noise produced can be heard<span class='pagenum'><a name="Page_80" id="Page_80">[Pg 80]</a></span> +at a distance of several feet. In all these cases a +slight shock is experienced so long as the contact +is preserved. The introduction of a piece of +paper between the parts in contact does not materially +interfere with the production of the +sounds, but the unpleasant effects of the shock +are avoided.</p> + +<a name="il096" id="il096"></a> +<div class="figcenter" style="width: 500px;"> +<img src="images/il096.png" width="500" height="242" alt="Fig. 12" title="Fig. 12" /> +<span class="caption">Fig. 12</span> +</div> + +<p>When an intermittent current from a Ruhmkorff's +coil is passed through the arms a musical +note can be perceived when the ear is closely +applied to the arm of the person experimented +upon. The sound seems to proceed from the +muscles of the fore-arm and from the biceps +muscle. Mr. Elisha Gray has also produced +audible effects by the passage of electricity +through the human body.</p> + +<p>An extremely loud musical note is occasioned +by the spark of a Ruhmkorff's coil when the +primary circuit is made and broken with sufficient +rapidity. When two breakers of different<span class='pagenum'><a name="Page_81" id="Page_81">[Pg 81]</a></span> +pitch are caused simultaneously to open and +close the primary circuit a double tone proceeds +from the spark.</p> + +<p>A curious discovery, which may be of interest +to you, has been made by Professor Blake. He +constructed a telephone in which a rod of soft +iron, about six feet in length, was used instead +of a permanent magnet. A friend sang a continuous +musical tone into the mouthpiece of a +telephone, like that shown in <a href="#il096">Fig. 12</a>, which was +connected with the soft iron instrument alluded +to above. It was found that the loudness of the +sound produced in this telephone varied with the +direction in which the iron rod was held, and +that the maximum effect was produced when the +rod was in the position of the dipping needle. +This curious discovery of Professor Blake has +been verified by myself.</p> + +<p>When a telephone is placed in circuit with a +telegraph line the telephone is found seemingly to +emit sounds on its own account. The most +extraordinary noises are often produced, the +causes of which are at present very obscure. +One class of sounds is produced by the inductive +influence of neighbouring wires and by leakage +from them, the signals of the Morse alphabet +passing over neighbouring wires being audible in +the telephone, and another class can be traced +to earth currents upon the wire, a curious modification +of this sound revealing the presence of +defective joints in the wire.</p> + +<p>Professor Blake informs me that he has been<span class='pagenum'><a name="Page_82" id="Page_82">[Pg 82]</a></span> +able to use the railroad track for conversational +purposes in place of a telegraph wire, and he +further states that when only one telephone was +connected with the track the sounds of Morse +operating were distinctly audible in the telephone, +although the nearest telegraph wires +were at least fifty feet distant.</p> + +<p>Professor Peirce has observed the most singular +sounds produced from a telephone in connection +with a telegraph wire during the aurora borealis, +and I have just heard of a curious phenomenon +lately observed by Dr. Channing. In the city +of Providence, Rhode Island, there is an over-house +wire about one mile in extent with a telephone +at either end. On one occasion the sound +of music and singing was faintly audible in one +of the telephones. It seemed as if some one were +practising vocal music with a pianoforte accompaniment. +The natural supposition was that +experiments were being made with the telephone +at the other end of the circuit, but upon inquiry +this proved not to have been the case. Attention +having thus been directed to the phenomenon, +a watch was kept upon the instruments, and +upon a subsequent occasion the same fact was +observed at both ends of the line by Dr. Channing +and his friends. It was proved that the +sounds continued for about two hours, and +usually commenced about the same time. A +searching examination of the line disclosed +nothing abnormal in its condition, and I am +unable to give you any explanation of this curious<span class='pagenum'><a name="Page_83" id="Page_83">[Pg 83]</a></span> +phenomenon. Dr. Channing has, however, +addressed a letter upon the subject to the editor +of one of the Providence papers, giving the names +of such songs as were recognized, and full details +of the observations, in the hope that publicity +may lead to the discovery of the performer, +and thus afford a solution of the mystery.</p> + +<p>My friend, Mr. Frederick A. Gower, communicated +to me a curious observation made by him +regarding the slight earth connection required +to establish a circuit for the telephone, and together +we carried on a series of experiments +with rather startling results. We took a couple +of telephones and an insulated wire about 100 +yards in length into a garden, and were enabled +to carry on conversation with the greatest ease +when we held in our hands what should have +been the earth wire, so that the connection with +the ground was formed at either end through +our bodies, our feet being clothed with cotton +socks and leather boots. The day was fine, and +the grass upon which we stood was seemingly +perfectly dry. Upon standing upon a gravel +walk the vocal sounds, though much diminished, +were still perfectly intelligible, and the same +result occurred when standing upon a brick wall +one foot in height, but no sound was audible +when one of us stood upon a block of freestone.</p> + +<p>One experiment which we made is so very +interesting that I must speak of it in detail. Mr. +Gower made earth connection at his end of the +line by standing upon a grass plot, whilst at the<span class='pagenum'><a name="Page_84" id="Page_84">[Pg 84]</a></span> +other end of the line I stood upon a wooden +board. I requested Mr. Gower to sing a continuous +musical note, and to my surprise the sound +was very distinctly audible from the telephone +in my hand. Upon examining my feet I discovered +that a single blade of grass was bent over +the edge of the board, and that my foot touched +it. The removal of this blade of grass was followed +by the cessation of the sound from the +telephone, and I found that the moment I +touched with the toe of my boot a blade of grass +or the petal of a daisy the sound was again +audible.</p> + +<p>The question will naturally arise, Through +what length of wire can the telephone be used? +In reply to this I may say that the maximum +amount of resistance through which the undulatory +current will pass, and yet retain sufficient +force to produce an audible sound at the distant +end, has yet to be determined; no difficulty has, +however, been experienced in laboratory experiments +in conversing through a resistance of +60,000 ohms, which has been the maximum at my +disposal. On one occasion, not having a rheostat +[for producing resistance] at hand, I passed +the current through the bodies of sixteen persons, +who stood hand in hand. The longest length of +real telegraph line through which I have attempted +to converse has been about 250 miles. +On this occasion no difficulty was experienced +so long as parallel lines were not in operation. +Sunday was chosen as the day on which it was<span class='pagenum'><a name="Page_85" id="Page_85">[Pg 85]</a></span> +probable other circuits would be at rest. Conversation +was carried on between myself, in New +York, and Mr. Thomas A. Watson, in Boston, +until the opening of business upon the other +wires. When this happened the vocal sounds +were very much diminished, but still audible. +It seemed, indeed, like talking through a storm. +Conversation, though possible, could be carried +on with difficulty, owing to the distracting +nature of the interfering currents.</p> + +<p>I am informed by my friend Mr. Preece that +conversation has been successfully carried on +through a submarine cable, sixty miles in length, +extending from Dartmouth to the Island of +Guernsey, by means of hand telephones.</p> + + +<h2><a name="PHOTOGRAPHING_THE_UNSEEN_THE" id="PHOTOGRAPHING_THE_UNSEEN_THE"></a>PHOTOGRAPHING THE UNSEEN: THE +ROENTGEN RAY</h2> +<p><span class='pagenum'><a name="Page_87" id="Page_87">[Pg 87]</a></span></p> +<span class="totoc"><a href="#toc">Top</a></span> +<h3><span class="smcap">H. J. W. Dam</span></h3> + +<div class="noteb"><p>[By permission from <i>McClure's Magazine</i>, April, 1896, +copyright by S. S. McClure, Limited.]</p></div> + + +<p>In all the history of scientific discovery there +has never been, perhaps, so general, rapid, and +dramatic an effect wrought on the scientific +centres of Europe as has followed, in the past +four weeks, upon an announcement made to the +Würzburg Physico-Medical Society, at their +December [1895] meeting, by Professor William +Konrad Röntgen, professor of physics at the +Royal University of Würzburg. The first news +which reached London was by telegraph from +Vienna to the effect that a Professor Röntgen, +until then the possessor of only a local fame in +the town mentioned, had discovered a new kind +of light, which penetrated and photographed +through everything. This news was received +with a mild interest, some amusement, and much +incredulity; and a week passed. Then, by mail +and telegraph, came daily clear indications of +the stir which the discovery was making in all +the great line of universities between Vienna and +Berlin. Then Röntgen's own report arrived, +so cool, so business-like, and so truly scientific in +character, that it left no doubt either of the<span class='pagenum'><a name="Page_88" id="Page_88">[Pg 88]</a></span> +truth or of the great importance of the preceding +reports. To-day, four weeks after the announcement, +Röntgen's name is apparently in every +scientific publication issued this week in Europe; +and accounts of his experiments, of the experiments +of others following his method, and of +theories as to the strange new force which he has +been the first to observe, fill pages of every scientific +journal that comes to hand. And before +the necessary time elapses for this article to +attain publication in America, it is in all ways +probable that the laboratories and lecture-rooms +of the United States will also be giving full evidence +of this contagious arousal of interest over +a discovery so strange that its importance cannot +yet be measured, its utility be even prophesied, +or its ultimate effect upon long established +scientific beliefs be even vaguely foretold.</p> + +<p>The Röntgen rays are certain invisible rays +resembling, in many respects, rays of light, which +are set free when a high-pressure electric current +is discharged through a vacuum tube. A vacuum +tube is a glass tube from which all the air, down +to one-millionth of an atmosphere, has been exhausted +after the insertion of a platinum wire +in either end of the tube for connection with the +two poles of a battery or induction coil. When +the discharge is sent through the tube, there proceeds +from the anode—that is, the wire which is +connected with the positive pole of the battery—certain +bands of light, varying in colour with +the colour of the glass. But these are insignificant<span class='pagenum'><a name="Page_89" id="Page_89">[Pg 89]</a></span> +in comparison with the brilliant glow which +shoots from the cathode, or negative wire. This +glow excites brilliant phosphorescence in glass +and many substances, and these “cathode rays,” +as they are called, were observed and studied by +Hertz; and more deeply by his assistant, Professor +Lenard, Lenard having, in 1894, reported +that the cathode rays would penetrate thin films +of aluminum, wood, and other substances, and +produce photographic results beyond. It was +left, however, for Professor Röntgen to discover +that during the discharge quite other rays +are set free, which differ greatly from those described +by Lenard as cathode rays. The most +marked difference between the two is the fact +that Röntgen rays are not deflected by a magnet, +indicating a very essential difference, while their +range and penetrative power are incomparably +greater. In fact, all those qualities which have +lent a sensational character to the discovery of +Röntgen's rays were mainly absent from those +of Lenard, to the end that, although Röntgen +has not been working in an entirely new field, he +has by common accord been freely granted all +the honors of a great discovery.</p> + +<p>Exactly what kind of a force Professor Röntgen +has discovered he does not know. As will +be seen below, he declines to call it a new kind +of light, or a new form of electricity. He has +given it the name of the X rays. Others speak +of it as the Röntgen rays. Thus far its results +only, and not its essence, are known. In the<span class='pagenum'><a name="Page_90" id="Page_90">[Pg 90]</a></span> +terminology of science it is generally called “a +new mode of motion,” or, in other words, a new +force. As to whether it is or not actually a force +new to science, or one of the known forces masquerading +under strange conditions, weighty +authorities are already arguing. More than one +eminent scientist has already affected to see in it +a key to the great mystery of the law of gravity. +All who have expressed themselves in print have +admitted, with more or less frankness, that, in +view of Röntgen's discovery, science must forthwith +revise, possibly to a revolutionary degree, +the long accepted theories concerning the phenomena +of light and sound. That the X rays, +in their mode of action, combine a strange +resemblance to both sound and light vibrations, +and are destined to materially affect, if they do +not greatly alter, our views of both phenomena, +is already certain; and beyond this is the opening +into a new and unknown field of physical knowledge, +concerning which speculation is already +eager, and experimental investigation already in +hand, in London, Paris, Berlin, and, perhaps, to +a greater or less extent, in every well-equipped +physical laboratory in Europe.</p> + +<p>This is the present scientific aspect of the discovery. +But, unlike most epoch-making results +from laboratories, this discovery is one which, to +a very unusual degree, is within the grasp of the +popular and non-technical imagination. Among +the other kinds of matter which these rays penetrate +with ease is human flesh. That a new<span class='pagenum'><a name="Page_91" id="Page_91">[Pg 91]</a></span> +photography has suddenly arisen which can +photograph the bones, and, before long, the organs +of the human body; that a light has been +found which can penetrate, so as to make a photographic +record, through everything from a +purse or a pocket to the walls of a room or a +house, is news which cannot fail to startle everybody. +That the eye of the physician or surgeon, +long baffled by the skin, and vainly seeking to +penetrate the unfortunate darkness of the human +body, is now to be supplemented by a camera, +making all the parts of the human body as +visible, in a way, as the exterior, appears certainly +to be a greater blessing to humanity than +even the Listerian antiseptic system of surgery; +and its benefits must inevitably be greater than +those conferred by Lister, great as the latter +have been. Already, in the few weeks since +Röntgen's announcement, the results of surgical +operations under the new system are growing +voluminous. In Berlin, not only new bone fractures +are being immediately photographed, but +joined fractures, as well, in order to examine the +results of recent surgical work. In Vienna, +imbedded bullets are being photographed, instead +of being probed for, and extracted with +comparative ease. In London, a wounded +sailor, completely paralyzed, whose injury was a +mystery, has been saved by the photographing +of an object imbedded in the spine, which, upon +extraction, proved to be a small knife-blade. +Operations for malformations, hitherto obscure,<span class='pagenum'><a name="Page_92" id="Page_92">[Pg 92]</a></span> +but now clearly revealed by the new photography, +are already becoming common, and are +being reported from all directions. Professor +Czermark of Graz has photographed the living +skull, denuded of flesh and hair, and has begun +the adaptation of the new photography to brain +study. The relation of the new rays to thought +rays is being eagerly discussed in what may be +called the non-exact circles and journals; and all +that numerous group of inquirers into the occult, +the believers in clairvoyance, spiritualism, +telepathy, and kindred orders of alleged phenomena, +are confident of finding in the new force +long-sought facts in proof of their claims. Professor +Neusser in Vienna has photographed gallstones +in the liver of one patient (the stone showing +snow-white in the negative), and a stone in +the bladder of another patient. His results so +far induce him to announce that all the organs +of the human body can, and will, shortly, be +photographed. Lannelongue of Paris has exhibited +to the Academy of Science photographs +of bones showing inherited tuberculosis which +had not otherwise revealed itself. Berlin has +already formed a society of forty for the immediate +prosecution of researches into both the character +of the new force and its physiological possibilities. +In the next few weeks these strange +announcements will be trebled or quadrupled, +giving the best evidence from all quarters of the +great future that awaits the Röntgen rays, and +the startling impetus to the universal search for<span class='pagenum'><a name="Page_93" id="Page_93">[Pg 93]</a></span> +knowledge that has come at the close of the nineteenth +century from the modest little laboratory +in the Pleicher Ring at Würzburg.</p> + +<p>The Physical Institute, Professor Röntgen's +particular domain, is a modest building of two +stories and basement, the upper story constituting +his private residence, and the remainder of +the building being given over to lecture rooms, +laboratories, and their attendant offices. At the +door I was met by an old serving-man of the +idolatrous order, whose pain was apparent when +I asked for “Professor” Röntgen, and he gently +corrected me with “Herr Doctor Röntgen.” +As it was evident, however, that we referred to +the same person, he conducted me along a wide, +bare hall, running the length of the building, +with blackboards and charts on the walls. At +the end he showed me into a small room on the +right. This contained a large table desk, and a +small table by the window, covered by photographs, +while the walls held rows of shelves +laden with laboratory and other records. An open +door led into a somewhat larger room, perhaps +twenty feet by fifteen, and I found myself gazing +into a laboratory which was the scene of the discovery—a +laboratory which, though in all ways +modest, is destined to be enduringly historical.</p> + +<p>There was a wide table shelf running along +the farther side, in front of the two windows, +which were high, and gave plenty of light. In +the centre was a stove; on the left, a small cabinet +whose shelves held the small objects which the<span class='pagenum'><a name="Page_94" id="Page_94">[Pg 94]</a></span> +professor had been using. There was a table in +the left-hand corner; and another small table—the +one on which living bones were first photographed—was +near the stove, and a Ruhmkorff +coil was on the right. The lesson of the laboratory +was eloquent. Compared, for instance, +with the elaborate, expensive, and complete +apparatus of, say, the University of London, or +of any of the great American universities, it was +bare and unassuming to a degree. It mutely +said that in the great march of science it is the +genius of man, and not the perfection of appliances, +that breaks new ground in the great +territory of the unknown. It also caused one +to wonder at and endeavour to imagine the great +things which are to be done through elaborate +appliances with the Röntgen rays—a field in +which the United States, with its foremost genius +in invention, will very possibly, if not probably, +take the lead—when the discoverer himself had +done so much with so little. Already, in a few +weeks, a skilled London operator, Mr. A. A. C. +Swinton, has reduced the necessary time of exposure +for Röntgen photographs from fifteen +minutes to four. He used, however, a Tesla oil +coil, discharged by twelve half-gallon Leyden +jars, with an alternating current of twenty thousand +volts' pressure. Here were no oil coils, +Leyden jars, or specially elaborate and expensive +machines. There were only a Ruhmkorff coil +and Crookes (vacuum) tube and the man himself.<span class='pagenum'><a name="Page_95" id="Page_95">[Pg 95]</a></span></p> + +<p>Professor Röntgen entered hurriedly, something +like an amiable gust of wind. He is a tall, +slender, and loose-limbed man, whose whole appearance +bespeaks enthusiasm and energy. He +wore a dark blue sack suit, and his long, dark +hair stood straight up from his forehead, as if +he were permanently electrified by his own enthusiasm. +His voice is full and deep, he speaks +rapidly, and, altogether, he seems clearly a man +who, once upon the track of a mystery which +appealed to him, would pursue it with unremitting +vigor. His eyes are kind, quick, and penetrating; +and there is no doubt that he much prefers +gazing at a Crookes tube to beholding a visitor, +visitors at present robbing him of much +valued time. The meeting was by appointment, +however, and his greeting was cordial and hearty. +In addition to his own language he speaks French +well and English scientifically, which is different +from speaking it popularly. These three tongues +being more or less within the equipment of his +visitor, the conversation proceeded on an international +or polyglot basis, so to speak, varying +at necessity's demand.</p> + +<p>It transpired in the course of inquiry, that the +professor is a married man and fifty years of age, +though his eyes have the enthusiasm of twenty-five. +He was born near Zurich, and educated +there, and completed his studies and took his +degree at Utrecht. He has been at Würzburg +about seven years, and had made no discoveries +which he considered of great importance prior<span class='pagenum'><a name="Page_96" id="Page_96">[Pg 96]</a></span> +to the one under consideration. These details +were given under good-natured protest, he failing +to understand why his personality should interest +the public. He declined to admire himself or his +results in any degree, and laughed at the idea of +being famous. The professor is too deeply interested +in science to waste any time in thinking +about himself. His emperor had feasted, flattered, +and decorated him, and he was loyally +grateful. It was evident, however, that fame +and applause had small attractions for him, compared +to the mysteries still hidden in the vacuum +tubes of the other room.</p> + +<p>“Now, then,” said he, smiling, and with some +impatience, when the preliminary questions at +which he chafed were over, “you have come to +see the invisible rays.”</p> + +<p>“Is the invisible visible?”</p> + +<p>“Not to the eye; but its results are. Come in +here.”</p> + +<div class="figcenter" style="width: 500px;"> +<img src="images/il113.png" width="500" height="260" alt="BONES OF A HUMAN FOOT PHOTOGRAPHED THROUGH THE FLESH" title="BONES OF A HUMAN FOOT PHOTOGRAPHED THROUGH THE FLESH" /> +<span class="caption">BONES OF A HUMAN FOOT PHOTOGRAPHED THROUGH THE FLESH<br /> +<small>From a photograph by A. A. C. Swinton, Victoria Street, London. Exposure, fifty-five seconds</small></span> +</div> + +<p>He led the way to the other square room mentioned, +and indicated the induction coil with +which his researches were made, an ordinary +Ruhmkorff coil, with a spark of from four to six +inches, charged by a current of twenty amperes. +Two wires led from the coil, through an open +door, into a smaller room on the right. In this +room was a small table carrying a Crookes tube +connected with the coil. The most striking +object in the room, however, was a huge and +mysterious tin box about seven feet high and +four feet square. It stood on end, like a huge<span class='pagenum'><a name="Page_97" id="Page_97">[Pg 97]</a></span> +packing case, its side being perhaps five inches +from the Crookes tube.</p> + +<p>The professor explained the mystery of the tin +box, to the effect that it was a device of his own +for obtaining a portable dark-room. When he +began his investigations he used the whole room, +as was shown by the heavy blinds and curtains so +arranged as to exclude the entrance of all interfering +light from the windows. In the side of the +tin box, at the point immediately against the +tube, was a circular sheet of aluminum one +millimetre in thickness, and perhaps eighteen +inches in diameter, soldered to the surrounding +tin. To study his rays the professor had only +to turn on the current, enter the box, close the +door, and in perfect darkness inspect only such +light or light effects as he had a right to consider +his own, hiding his light, in fact, not under the +Biblical bushel, but in a more commodious box.</p> + +<p>“Step inside,” said he, opening the door, which +was on the side of the box farthest from the tube. +I immediately did so, not altogether certain +whether my skeleton was to be photographed +for general inspection, or my secret thoughts +held up to light on a glass plate. “You will find +a sheet of barium paper on the shelf,” he added, +and then went away to the coil. The door was +closed, and the interior of the box became black +darkness. The first thing I found was a wooden +stool, on which I resolved to sit. Then I found +the shelf on the side next the tube, and then the +sheet of paper prepared with barium platinocyanide.<span class='pagenum'><a name="Page_98" id="Page_98">[Pg 98]</a></span> +I was thus being shown the first phenomenon +which attracted the discoverer's attention +and led to his discovery, namely, the +passage of rays, themselves wholly invisible, +whose presence was only indicated by the effect +they produced on a piece of sensitized photographic +paper.</p> + +<p>A moment later, the black darkness was penetrated +by the rapid snapping sound of the high-pressure +current in action, and I knew that the +tube outside was glowing. I held the sheet vertically +on the shelf, perhaps four inches from the +plate. There was no change, however, and +nothing was visible.</p> + +<p>“Do you see anything?” he called.</p> + +<p>“No.”</p> + +<p>“The tension is not high enough;” and he proceeded +to increase the pressure by operating an +apparatus of mercury in long vertical tubes acted +upon automatically by a weight lever which +stood near the coil. In a few moments the +sound of the discharge again began, and then +I made my first acquaintance with the Röntgen +rays.</p> + +<p>The moment the current passed, the paper +began to glow. A yellowish green light spread +all over its surface in clouds, waves and flashes. +The yellow-green luminescence, all the stranger +and stronger in the darkness, trembled, wavered, +and floated over the paper, in rhythm with the +snapping of the discharge. Through the metal +plate, the paper, myself, and the tin box, the<span class='pagenum'><a name="Page_99" id="Page_99">[Pg 99]</a></span> +invisible rays were flying, with an effect strange, +interesting and uncanny. The metal plate +seemed to offer no appreciable resistance to the +flying force, and the light was as rich and full as +if nothing lay between the paper and the tube.</p> + +<p>“Put the book up,” said the professor.</p> + +<p>I felt upon the shelf, in the darkness, a heavy +book, two inches in thickness, and placed this +against the plate. It made no difference. The +rays flew through the metal and the book as if +neither had been there, and the waves of light, +rolling cloud-like over the paper, showed no +change in brightness. It was a clear, material +illustration of the ease with which paper and +wood are penetrated. And then I laid book +and paper down, and put my eyes against the +rays. All was blackness, and I neither saw nor +felt anything. The discharge was in full force, +and the rays were flying through my head, and, +for all I knew, through the side of the box behind +me. But they were invisible and impalpable. +They gave no sensation whatever. Whatever +the mysterious rays may be, they are not +to be seen, and are to be judged only by their +works.</p> + +<p>I was loath to leave this historical tin box, but +time pressed. I thanked the professor, who was +happy in the reality of his discovery and the +music of his sparks. Then I said: “Where did +you first photograph living bones?”</p> + +<p>“Here,” he said, leading the way into the +room where the coil stood. He pointed to a<span class='pagenum'><a name="Page_100" id="Page_100">[Pg 100]</a></span> +table on which was another—the latter a small +short-legged wooden one with more the shape +and size of a wooden seat. It was two feet +square and painted coal black. I viewed it with +interest. I would have bought it, for the little +table on which light was first sent through the +human body will some day be a great historical +curiosity; but it was not for sale. A photograph +of it would have been a consolation, but for +several reasons one was not to be had at present. +However, the historical table was there, and +was duly inspected.</p> + +<p>“How did you take the first hand photograph?” +I asked.</p> + +<p>The professor went over to a shelf by the window, +where lay a number of prepared glass plates, +closely wrapped in black paper. He put a +Crookes tube underneath the table, a few inches +from the under side of its top. Then he laid his +hand flat on the top of the table, and placed the +glass plate loosely on his hand.</p> + +<p>“You ought to have your portrait painted in +that attitude,” I suggested.</p> + +<p>“No, that is nonsense,” said he, smiling.</p> + +<p>“Or be photographed.” This suggestion was +made with a deeply hidden purpose.</p> + +<p>The rays from the Röntgen eyes instantly +penetrated the deeply hidden purpose. “Oh, +no,” said he; “I can't let you make pictures of +me. I am too busy.” Clearly the professor was +entirely too modest to gratify the wishes of the +curious world.<span class='pagenum'><a name="Page_101" id="Page_101">[Pg 101]</a></span></p> + +<p>“Now, Professor,” said I, “will you tell me +the history of the discovery?”</p> + +<p>“There is no history,” he said. “I have been +for a long time interested in the problem of the +cathode rays from a vacuum tube as studied by +Hertz and Lenard. I had followed their and +other researches with great interest, and determined, +as soon as I had the time, to make some +researches of my own. This time I found at the +close of last October. I had been at work for +some days when I discovered something new.”</p> + +<p>“What was the date?”</p> + +<p>“The eighth of November.”</p> + +<p>“And what was the discovery?”</p> + +<p>“I was working with a Crookes tube covered +by a shield of black cardboard. A piece of +barium platinocyanide paper lay on the bench +there. I had been passing a current through +the tube, and I noticed a peculiar black line +across the paper.”</p> + +<p>“What of that?”</p> + +<p>“The effect was one which could only be produced, +in ordinary parlance, by the passage of +light. No light could come from the tube, because +the shield which covered it was impervious +to any light known, even that of the electric arc.”</p> + +<p>“And what did you think?”</p> + +<p>“I did not think; I investigated. I assumed +that the effect must have come from the tube, +since its character indicated that it could come +from nowhere else. I tested it. In a few minutes +there was no doubt about it. Rays were<span class='pagenum'><a name="Page_102" id="Page_102">[Pg 102]</a></span> +coming from the tube which had a luminescent +effect upon the paper. I tried it successfully at +greater and greater distances, even at two +metres. It seemed at first a new kind of invisible +light. It was clearly something new, something +unrecorded.”</p> + +<p>“Is it light?”</p> + +<p>“No.”</p> + +<p>“Is it electricity?”</p> + +<p>“Not in any known form.”</p> + +<p>“What is it?”</p> + +<p>“I don't know.”</p> + +<p>And the discoverer of the X rays thus stated +as calmly his ignorance of their essence as has +everybody else who has written on the phenomena +thus far.</p> + +<p>“Having discovered the existence of a new +kind of rays, I of course began to investigate +what they would do.” He took up a series of +cabinet-sized photographs. “It soon appeared +from tests that the rays had penetrative powers +to a degree hitherto unknown. They penetrated +paper, wood, and cloth with ease; and the thickness +of the substance made no perceptible difference, +within reasonable limits.” He showed +photographs of a box of laboratory weights of +platinum, aluminum, and brass, they and the +brass hinges all having been photographed from +a closed box, without any indication of the box. +Also a photograph of a coil of fine wire, wound +on a wooden spool, the wire having been photographed, +and the wood omitted. “The rays,”<span class='pagenum'><a name="Page_103" id="Page_103">[Pg 103]</a></span> +he continued, “passed through all the metals +tested, with a facility varying, roughly speaking, +with the density of the metal. These phenomena +I have discussed carefully in my report +to the Würzburg society, and you will find all the +technical results therein stated.” He showed a +photograph of a small sheet of zinc. This was +composed of smaller plates soldered laterally with +solders of different metallic proportions. The +differing lines of shadow, caused by the difference +in the solders, were visible evidence that a new +means of detecting flaws and chemical variations +in metals had been found. A photograph of a +compass showed the needle and dial taken through +the closed brass cover. The markings of the +dial were in red metallic paint, and thus interfered +with the rays, and were reproduced. +“Since the rays had this great penetrative power, +it seemed natural that they should penetrate +flesh, and so it proved in photographing the +hand, as I showed you.”</p> + +<p>A detailed discussion of the characteristics of +his rays the professor considered unprofitable +and unnecessary. He believes, though, that +these mysterious radiations are not light, because +their behaviour is essentially different from that +of light rays, even those light rays which are +themselves invisible. The Röntgen rays cannot +be reflected by reflecting surfaces, concentrated +by lenses, or refracted or diffracted. They produce +photographic action on a sensitive film, but +their action is weak as yet, and herein lies the<span class='pagenum'><a name="Page_104" id="Page_104">[Pg 104]</a></span> +first important field of their development. The +professor's exposures were comparatively long—an +average of fifteen minutes in easily penetrable +media, and half an hour or more in photographing +the bones of the hand. Concerning vacuum +tubes, he said that he preferred the Hittorf, +because it had the most perfect vacuum, the +highest degree of air exhaustion being the consummation +most desirable. In answer to a +question, “What of the future?” he said:</p> + +<p>“I am not a prophet, and I am opposed to +prophesying. I am pursuing my investigations, +and as fast as my results are verified I shall make +them public.”</p> + +<p>“Do you think the rays can be so modified as +to photograph the organs of the human body?”</p> + +<p>In answer he took up the photograph of the +box of weights. “Here are already modifications,” +he said, indicating the various degrees of +shadow produced by the aluminum, platinum, +and brass weights, the brass hinges, and even the +metallic stamped lettering on the cover of the +box, which was faintly perceptible.</p> + +<p>“But Professor Neusser has already announced +that the photographing of the various organs is +possible.”</p> + +<p>“We shall see what we shall see,” he said. +“We have the start now; the development will +follow in time.”</p> + +<p>“You know the apparatus for introducing the +electric light into the stomach?”</p> + +<p>“Yes.”<span class='pagenum'><a name="Page_105" id="Page_105">[Pg 105]</a></span></p> + +<p>“Do you think that this electric light will +become a vacuum tube for photographing, +from the stomach, any part of the abdomen or +thorax?”</p> + +<p>The idea of swallowing a Crookes tube, and +sending a high frequency current down into one's +stomach, seemed to him exceedingly funny. +“When I have done it, I will tell you,” he said, +smiling, resolute in abiding by results.</p> + +<p>“There is much to do, and I am busy, very +busy,” he said in conclusion. He extended his +hand in farewell, his eyes already wandering +toward his work in the inside room. And his +visitor promptly left him; the words, “I am +busy,” said in all sincerity, seeming to describe +in a single phrase the essence of his +character and the watchword of a very unusual +man.</p> + +<p>Returning by way of Berlin, I called upon +Herr Spies of the Urania, whose photographs +after the Röntgen method were the first made +public, and have been the best seen thus far. In +speaking of the discovery he said:</p> + +<p>“I applied it, as soon as the penetration of +flesh was apparent, to the photograph of a man's +hand. Something in it had pained him for +years, and the photograph at once exhibited a +small foreign object, as you can see;” and he +exhibited a copy of the photograph in question. +“The speck there is a small piece of glass, which +was immediately extracted, and which, in all +probability, would have otherwise remained in<span class='pagenum'><a name="Page_106" id="Page_106">[Pg 106]</a></span> +the man's hand to the end of his days.” All +of which indicates that the needle which +has pursued its travels in so many persons, +through so many years, will be suppressed by +the camera.</p> + +<p>“My next object is to photograph the bones +of the entire leg,” continued Herr Spies. “I +anticipate no difficulty, though it requires some +thought in manipulation.”</p> + +<p>It will be seen that the Röntgen rays and their +marvellous practical possibilities are still in their +infancy. The first successful modification of the +action of the rays so that the varying densities of +bodily organs will enable them to be photographed +will bring all such morbid growths as tumours +and cancers into the photographic field, to +say nothing of vital organs which may be abnormally +developed or degenerate. How much +this means to medical and surgical practice it requires +little imagination to conceive. Diagnosis, +long a painfully uncertain science, has received an +unexpected and wonderful assistant; and how +greatly the world will benefit thereby, how much +pain will be saved, only the future can determine. +In science a new door has been opened where none +was known to exist, and a side-light on phenomena +has appeared, of which the results may +prove as penetrating and astonishing as the +Röntgen rays themselves. The most agreeable +feature of the discovery is the opportunity it +gives for other hands to help; and the work of +these hands will add many new words to the<span class='pagenum'><a name="Page_107" id="Page_107">[Pg 107]</a></span> +dictionaries, many new facts to science, and, in +the years long ahead of us, fill many more volumes +than there are paragraphs in this brief and +imperfect account.</p> + + + +<h2><a name="THE_WIRELESS_TELEGRAPH" id="THE_WIRELESS_TELEGRAPH"></a>THE WIRELESS TELEGRAPH</h2> +<p><span class='pagenum'><a name="Page_109" id="Page_109">[Pg 109]</a></span></p> +<span class="totoc"><a href="#toc">Top</a></span> +<h3><span class="smcap">George Iles</span></h3> + +<div class="noteb"><p>[From “Flame, Electricity and the Camera,” copyright +by Doubleday, Page & Co., New York.]</p></div> + + +<p>In a series of experiments interesting enough +but barren of utility, the water of a canal, river, +or bay has often served as a conductor for the +telegraph. Among the electricians who have +thus impressed water into their service was +Professor Morse. In 1842 he sent a few signals +across the channel from Castle Garden, New +York, to Governor's Island, a distance of a mile. +With much better results, he sent messages, +later in the same year, from one side of the canal +at Washington to the other, a distance of eighty +feet, employing large copper plates at each terminal. +The enormous current required to overcome +the resistance of water has barred this +method from practical adoption.</p> + +<p>We pass, therefore, to electrical communication +as effected by induction—the influence which +one conductor exerts on another through an intervening +insulator. At the outset we shall do +well to bear in mind that magnetic phenomena, +which are so closely akin to electrical, are always +inductive. To observe a common example of +magnetic induction, we have only to move a +horseshoe magnet in the vicinity of a compass<span class='pagenum'><a name="Page_110" id="Page_110">[Pg 110]</a></span> +needle, which will instantly sway about as if +blown hither and thither by a sharp draught of +air. This action takes place if a slate, a pane of +glass, or a shingle is interposed between the +needle and its perturber. There is no known +insulator for magnetism, and an induction of this +kind exerts itself perceptibly for many yards +when large masses of iron are polarised, so that +the derangement of compasses at sea from moving +iron objects aboard ship, or from ferric ores +underlying a sea-coast, is a constant peril to the +mariner.</p> + +<p>Electrical conductors behave much like magnetic +masses. A current conveyed by a conductor +induces a counter-current in all surrounding +bodies, and in a degree proportioned to their +conductive power. This effect is, of course, +greatest upon the bodies nearest at hand, and we +have already remarked its serious retarding +effect in ocean telegraphy. When the original +current is of high intensity, it can induce a perceptible +current in another wire at a distance of +several miles. In 1842 Henry remarked that +electric waves had this quality, but in that early +day of electrical interpretation the full significance +of the fact eluded him. In the top room +of his house he produced a spark an inch long, +which induced currents in wires stretched in +his cellar, through two thick floors and two rooms +which came between. Induction of this sort +causes the annoyance, familiar in single telephonic +circuits, of being obliged to overhear<span class='pagenum'><a name="Page_111" id="Page_111">[Pg 111]</a></span> +other subscribers, whose wires are often far away +from our own.</p> + +<p>The first practical use of induced currents in +telegraphy was when Mr. Edison, in 1885, enabled +the trains on a line of the Staten Island Railroad +to be kept in constant communication with a +telegraphic wire, suspended in the ordinary way +beside the track. The roof of a car was of insulated +metal, and every tap of an operator's +key within the walls electrified the roof just long +enough to induce a brief pulse through the telegraphic +circuit. In sending a message to the +car this wire was, moment by moment, electrified, +inducing a response first in the car roof, and next +in the “sounder” beneath it. This remarkable +apparatus, afterward used on the Lehigh Valley +Railroad, was discontinued from lack of commercial +support, although it would seem to be +advantageous to maintain such a service on other +than commercial grounds. In case of chance +obstructions on the track, or other peril, to be +able to communicate at any moment with a +train as it speeds along might mean safety instead +of disaster. The chief item in the cost of +this system is the large outlay for a special telegraphic +wire.</p> + +<p>The next electrician to employ induced currents +in telegraphy was Mr. (now Sir) William +H. Preece, the engineer then at the head of the +British telegraph system. Let one example of +his work be cited. In 1896 a cable was laid between +Lavernock, near Cardiff, on the Bristol<span class='pagenum'><a name="Page_112" id="Page_112">[Pg 112]</a></span> +Channel, and Flat Holme, an island three and a +third miles off. As the channel at this point is +a much-frequented route and anchor ground, +the cable was broken again and again. As a +substitute for it Mr. Preece, in 1898, strung wires +along the opposite shores, and found that an +electric pulse sent through one wire instantly +made itself heard in a telephone connected with +the other. It would seem that in this etheric +form of telegraphy the two opposite lines of +wire must be each as long as the distance which +separates them; therefore, to communicate across +the English Channel from Dover to Calais would +require a line along each coast at least twenty +miles in length. Where such lines exist for +ordinary telegraphy, they might easily lend themselves +to the Preece system of signalling in case +a submarine cable were to part.</p> + +<p>Marconi, adopting electrostatic instead of +electro-magnetic waves, has won striking results. +Let us note the chief of his forerunners, as they +prepared the way for him. In 1864 Maxwell +observed that electricity and light have the same +velocity, 186,400 miles a second, and he formulated +the theory that electricity propagates itself +in waves which differ from those of light only +in being longer. This was proved to be true by +Hertz, who in 1888 showed that where alternating +currents of very high frequency were set up +in an open circuit, the energy might be conveyed +entirely away from the circuit into the surrounding +space as electric waves. His detector was<span class='pagenum'><a name="Page_113" id="Page_113">[Pg 113]</a></span> +a nearly closed circle of wire, the ends being +soldered to metal balls almost in contact. With +this simple apparatus he demonstrated that +electric waves move with the speed of light, and +that they can be reflected and refracted precisely +as if they formed a visible beam. At a +certain intensity of strain the air insulation broke +down, and the air became a conductor. This +phenomenon of passing quite suddenly from a +non-conductive to a conductive state is, as we +shall duly see, also to be noted when air or other +gases are exposed to the X ray.</p> + +<p>Now for the effect of electric waves such as +Hertz produced, when they impinge upon substances +reduced to powder or filings. Conductors, +such as the metals, are of inestimable service to +the electrician; of equal value are non-conductors, +such as glass and gutta-percha, as they strictly +fence in an electric stream. A third and remarkable +vista opens to experiment when it deals +with substances which, in their normal state, are +non-conductive, but which, agitated by an electric +wave, instantly become conductive in a high +degree. As long ago as 1866 Mr. S. A. Varley +noticed that black lead, reduced to a loose dust, +effectually intercepted a current from fifty +Daniell cells, although the battery poles were +very near each other. When he increased the +electric tension four- to six-fold, the black-lead +particles at once compacted themselves so as to +form a bridge of excellent conductivity. On this +principle he invented a lightning-protector for<span class='pagenum'><a name="Page_114" id="Page_114">[Pg 114]</a></span> +electrical instruments, the incoming flash causing +a tiny heap of carbon dust to provide it with a +path through which it could safely pass to the +earth. Professor Temistocle Calzecchi Onesti of +Fermo, in 1885, in an independent series of researches, +discovered that a mass of powdered +copper is a non-conductor until an electric wave +beats upon it; then, in an instant, the mass resolves +itself into a conductor almost as efficient +as if it were a stout, unbroken wire. Professor +Edouard Branly of Paris, in 1891, on this principle +devised a coherer, which passed from resistance +to invitation when subjected to an electric +impulse from afar. He enhanced the value of +his device by the vital discovery that the conductivity +bestowed upon filings by electric discharges +could be destroyed by simply shaking +or tapping them apart.</p> + +<p>In a homely way the principle of the coherer is +often illustrated in ordinary telegraphic practice. +An operator notices that his instrument is not +working well, and he suspects that at some point +in his circuit there is a defective contact. A little +dirt, or oxide, or dampness, has come in between +two metallic surfaces; to be sure, they still touch +each other, but not in the firm and perfect way +demanded for his work. Accordingly he sends a +powerful current abruptly into the line, which +clears its path thoroughly, brushes aside dirt, +oxide, or moisture, and the circuit once more is as +it should be. In all likelihood, the coherer is +acted upon in the same way. Among the physicists<span class='pagenum'><a name="Page_115" id="Page_115">[Pg 115]</a></span> +who studied it in its original form was Dr. +Oliver J. Lodge. He improved it so much that, +in 1894, at the Royal Institution in London, he +was able to show it as an electric eye that registered +the impact of invisible rays at a distance of +more than forty yards. He made bold to say +that this distance might be raised to half a mile.</p> + +<p>As early as 1879 Professor D. E. Hughes began +a series of experiments in wireless telegraphy, +on much the lines which in other hands have now +reached commercial as well as scientific success. +Professor Hughes was the inventor of the microphone, +and that instrument, he declared, affords +an unrivalled means of receiving wireless messages, +since it requires no tapping to restore its +non-conductivity. In his researches this investigator +was convinced that his signals were +propagated, not by electro-magnetic induction, +but by aerial electric waves spreading out from +an electric spark. Early in 1880 he showed his +apparatus to Professor Stokes, who observed its +operation carefully. His dictum was that he +saw nothing which could not be explained by +known electro-magnetic effects. This erroneous +judgment so discouraged Professor Hughes that +he desisted from following up his experiments, +and thus, in all probability, the birth of the +wireless telegraph was for several years delayed.<a name="FNanchor_3_3" id="FNanchor_3_3"></a><a href="#Footnote_3_3" class="fnanchor">[3]</a><span class='pagenum'><a name="Page_116" id="Page_116">[Pg 116]</a></span></p> + +<a name="Fig_71" id="Fig_71"></a> +<div class="figcenter" style="width: 500px;"> +<img src="images/il134.png" width="500" height="151" alt="Fig. 71.—Marconi coherer, enlarged view" title="" /> +<span class="caption">Fig. 71.—Marconi coherer, enlarged view</span> +</div> + +<p>The coherer, as improved by Marconi, is a glass +tube about one and one-half inches long and +about one-twelfth of an inch in internal diameter. +The electrodes are inserted in this tube so as +almost to touch; between them is about one-thirtieth +of an inch filled with a pinch of the +responsive mixture which forms the pivot of +the whole contrivance. This mixture is 90 per +cent. nickel filings, 10 per cent. hard silver filings, +and a mere trace of mercury; the tube is exhausted +of air to within one ten-thousandth part +(<a href="#Fig_71">Fig. 71</a>). How does this trifle of metallic dust +manage loudly to utter its signals through a +telegraphic sounder, or forcibly indent them +upon a moving strip of paper? Not directly, +but indirectly, as the very last refinement of initiation. +Let us imagine an ordinary telegraphic +battery strong enough loudly to tick out a message. +Be it ever so strong it remains silent +until its circuit is completed, and for that completion +the merest touch suffices. Now the +thread of dust in the coherer forms part of such +a telegraphic circuit: as loose dust it is an effectual<span class='pagenum'><a name="Page_117" id="Page_117">[Pg 117]</a></span> +bar and obstacle, under the influence of +electric waves from afar it changes instantly to a +coherent metallic link which at once completes +the circuit and delivers the message.</p> + +<p>An electric impulse, almost too attenuated for +computation, is here able to effect such a change +in a pinch of dust that it becomes a free avenue +instead of a barricade. Through that avenue a +powerful blow from a local store of energy makes +itself heard and felt. No device of the trigger +class is comparable with this in delicacy. An +instant after a signal has taken its way through +the coherer a small hammer strikes the tiny tube, +jarring its particles asunder, so that they resume +their normal state of high resistance. We may +well be astonished at the sensitiveness of the +metallic filings to an electric wave originating +many miles away, but let us remember how +clearly the eye can see a bright lamp at the same +distance as it sheds a sister beam. Thus far no +substance has been discovered with a mechanical +responsiveness to so feeble a ray of light; in the +world of nature and art the coherer stands alone. +The electric waves employed by Marconi are +about four feet long, or have a frequency of about +250,000,000 per second. Such undulations pass +readily through brick or stone walls, through +common roofs and floors—indeed, through all +substances which are non-conductive to electric +waves of ordinary length. Were the energy of a +Marconi sending-instrument applied to an arc-lamp, +it would generate a beam of a thousand<span class='pagenum'><a name="Page_118" id="Page_118">[Pg 118]</a></span> +candle-power. We have thus a means of comparing +the sensitiveness of the retina to light +with the responsiveness of the Marconi coherer +to electric waves, after both radiations have +undergone a journey of miles.</p> + +<p>An essential feature of this method of etheric +telegraphy, due to Marconi himself, is the suspension +of a perpendicular wire at each terminus, +its length twenty feet for stations a mile apart, +forty feet for four miles, and so on, the telegraphic +distance increasing as the square of the length +of suspended wire. In the Kingstown regatta, +July, 1898, Marconi sent from a yacht under full +steam a report to the shore without the loss of a +moment from start to finish. This feat was repeated +during the protracted contest between +the <i>Columbia</i> and the <i>Shamrock</i> yachts in New +York Bay, October, 1899. On March 28, 1899, +Marconi signals put Wimereux, two miles north +of Boulogne, in communication with the South +Foreland Lighthouse, thirty-two miles off.<a name="FNanchor_4_4" id="FNanchor_4_4"></a><a href="#Footnote_4_4" class="fnanchor">[4]</a> +In August, 1899, during the manoeuvres of the<span class='pagenum'><a name="Page_119" id="Page_119">[Pg 119]</a></span> +British navy, similar messages were sent as far +as eighty miles. It was clearly demonstrated +that a new power had been placed in the hands +of a naval commander. “A touch on a button +in a flagship is all that is now needed to initiate +every tactical evolution in a fleet, and insure an +almost automatic precision in the resulting +movements of the ships. The flashing lantern is +superseded at night, flags and the semaphore by +day, or, if these are retained, it is for services +purely auxiliary. The hideous and bewildering +shrieks of the steam-siren need no longer be heard +in a fog, and the uncertain system of gun signals +will soon become a thing of the past.” The interest +of the naval and military strategist in the +Marconi apparatus extends far beyond its communication +of intelligence. Any electrical appliance +whatever may be set in motion by the +same wave that actuates a telegraphic sounder. +A fuse may be ignited, or a motor started and +directed, by apparatus connected with the coherer, +for all its minuteness. Mr. Walter Jamieson<span class='pagenum'><a name="Page_120" id="Page_120">[Pg 120]</a></span> +and Mr. John Trotter have devised means for +the direction of torpedoes by ether waves, such +as those set at work in the wireless telegraph. +Two rods projecting above the surface of the +water receive the waves, and are in circuit with a +coherer and a relay. At the will of the distant +operator a hollow wire coil bearing a current draws +in an iron core either to the right or to the left, +moving the helm accordingly.</p> + +<p>As the news of the success of the Marconi telegraph +made its way to the London Stock Exchange +there was a fall in the shares of cable +companies. The fear of rivalry from the new +invention was baseless. As but fifteen words +a minute are transmissible by the Marconi system, +it evidently does not compete with a cable, +such as that between France and England, which +can transmit 2,500 words a minute without difficulty. +The Marconi telegraph comes less as a +competitor to old systems than as a mode of +communication which creates a field of its own. +We have seen what it may accomplish in war, +far outdoing any feat possible to other apparatus, +acoustic, luminous, or electrical. In quite +as striking fashion does it break new ground in +the service of commerce and trade. It enables +lighthouses continually to spell their names, so +that receivers aboard ship may give the steersmen +their bearings even in storm and fog. In +the crowded condition of the steamship “lanes” +which cross the Atlantic, a priceless security +against collision is afforded the man at the helm.<span class='pagenum'><a name="Page_121" id="Page_121">[Pg 121]</a></span> +On November 15, 1899, Marconi telegraphed +from the American liner <i>St. Paul</i> to the Needles, +sixty-six nautical miles away. On December 11 +and 12, 1901, he received wireless signals near +St. John's, Newfoundland, sent from Poldhu, +Cornwall, England, or a distance of 1,800 miles,—a +feat which astonished the world. In many +cases the telegraphic business to an island is too +small to warrant the laying of a cable; hence +we find that Trinidad and Tobago are to be +joined by the wireless system, as also five islands +of the Hawaiian group, eight to sixty-one miles +apart.</p> + +<p>A weak point in the first Marconi apparatus +was that anybody within the working radius of +the sending-instrument could read its messages. +To modify this objection secret codes were at +times employed, as in commerce and diplomacy. +A complete deliverance from this difficulty is +promised in attuning a transmitter and a receiver +to the same note, so that one receiver, and no +other, shall respond to a particular frequency of +impulses. The experiments which indicate success +in this vital particular have been conducted +by Professor Lodge.</p> + +<a name="Fig_73" id="Fig_73"></a> +<div class="figcenter" style="width: 500px;"> +<img src="images/il140.png" width="500" height="48" alt="Fig. 73—Discontinuous electric waves" title="Fig. 73—Discontinuous electric waves" /> +<span class="caption">Fig. 73—Discontinuous electric waves</span> +</div> +<a name="Fig_74" id="Fig_74"></a> +<div class="figright" style="width: 200px;"> +<img src="images/il141.png" width="200" height="285" alt="Fig. 74—Wehnelt interrupter" title="Fig. 74—Wehnelt interrupter" /> +<span class="caption">Fig. 74—Wehnelt interrupter</span> +</div> +<p>When electricians, twenty years ago, committed +energy to a wire and thus enabled it to go +round a corner, they felt that they had done well. +The Hertz waves sent abroad by Marconi ask no +wire, as they find their way, not round a corner, +but through a corner. On May 1, 1899, a party +of French officers on board the <i>Ibis</i> at Sangatte,<span class='pagenum'><a name="Page_122" id="Page_122">[Pg 122]</a></span> +near Calais, spoke to Wimereux by means of a +Marconi apparatus, with Cape Grisnez, a lofty +promontory, intervening. In ascertaining how +much the earth and the sea may obstruct the +waves of Hertz there is a broad and fruitful field +for investigation. “It may be,” says Professor +John Trowbridge, “that such long electrical +waves roll around the surface of such obstructions +very much as waves of sound and of water +would do.”</p> + +<p>It is singular how discoveries sometimes arrive +abreast of each other so as to render mutual aid, +or supply a pressing want almost as soon as it is +felt. The coherer in its present form is actuated +by waves of comparatively low frequency, +which rise from zero to full height in extremely +brief periods, and are separated by periods decidedly +longer (<a href="#Fig_73">Fig. 73</a>). What is needed is a +plan by which the waves may flow either continuously +or so near together that they may lend +themselves to attuning. Dr. Wehnelt, by an +extraordinary discovery, may, in all likelihood, +provide the lacking device in the form of his interrupter, +which breaks an electric circuit as often +as two thousand times a second. The means for<span class='pagenum'><a name="Page_123" id="Page_123">[Pg 123]</a></span> +this amazing performance are simplicity itself +(<a href="#Fig_74">Fig. 74</a>). A jar, <i>a</i>, containing a solution of sulphuric +acid has two electrodes +immersed in it; one +of them is a lead plate +of large surface, <i>b</i>; the +other is a small platinum +wire which protrudes +from a glass tube, <i>d</i>. A +current passing through +the cell between the two +metals at <i>c</i> is interrupted, +in ordinary cases five +hundred times a second, +and in extreme cases +four times as often, +by bubbles of gas given off from the wire instant +by instant.</p> + + +<div class="footnotes"><h3>FOOTNOTES:</h3> + +<div class="footnote"><p><a name="Footnote_3_3" id="Footnote_3_3"></a><a href="#FNanchor_3_3"><span class="label">[3]</span></a> “History of the Wireless Telegraph,” by J. J. Fahie. +Edinburgh and London, William Blackwood & Sons; New +York, Dodd, Mead & Co., 1899. This work is full of interesting +detail, well illustrated.</p></div> + +<div class="footnote"><p><a name="Footnote_4_4" id="Footnote_4_4"></a><a href="#FNanchor_4_4"><span class="label">[4]</span></a> The value of wireless telegraphy in relation to disasters +at sea was proved in a remarkable way yesterday morning. +While the Channel was enveloped in a dense fog, which had +lasted throughout the greater part of the night, the East +Goodwin Lightship had a very narrow escape from sinking +at her moorings by being run into by the steamship <i>R. F. +Matthews</i>, 1,964 tons gross burden, of London, outward +bound from the Thames. The East Goodwin Lightship +is one of four such vessels marking the Goodwin Sands, and, +curiously enough, it happens to be the one ship which has +been fitted out with Signor Marconi's installation for wireless +telegraphy. The vessel was moored about twelve miles to the northeast of the South Foreland Lighthouse (where +there is another wireless-telegraphy installation), and she +is about ten miles from the shore, being directly opposite +Deal. The information regarding the collision was at once +communicated by wireless telegraphy from the disabled +lightship to the South Foreland Lighthouse, where Mr. +Bullock, assistant to Signor Marconi, received the following +message: “We have just been run into by the steamer +<i>R. F. Matthews</i> of London. Steamship is standing by us. +Our bows very badly damaged.” Mr. Bullock immediately +forwarded this information to the Trinity House authorities +at Ramsgate.—<i>Times</i>, April 29, 1899.</p></div> +</div> + + +<h2><a name="ELECTRICITY_WHAT_ITS_MASTERY" id="ELECTRICITY_WHAT_ITS_MASTERY"></a>ELECTRICITY, WHAT ITS MASTERY<br /> +MEANS: WITH A REVIEW<br /> +AND A PROSPECT</h2> +<p><span class='pagenum'><a name="Page_125" id="Page_125">[Pg 125]</a></span></p> +<span class="totoc"><a href="#toc">Top</a></span> +<h3><span class="smcap">George Iles</span></h3> + +<div class="noteb"><p>[From “Flame, Electricity and the Camera,” copyright +by Doubleday, Page & Co., New York.]</p></div> + + +<p>With the mastery of electricity man enters +upon his first real sovereignty of nature. As we +hear the whirr of the dynamo or listen at the telephone, +as we turn the button of an incandescent +lamp or travel in an electromobile, we are partakers +in a revolution more swift and profound +than has ever before been enacted upon earth. +Until the nineteenth century fire was justly accounted +the most useful and versatile servant of +man. To-day electricity is doing all that fire +ever did, and doing it better, while it accomplishes +uncounted tasks far beyond the reach of +flame, however ingeniously applied. We may +thus observe under our eyes just such an impetus +to human intelligence and power as when fire +was first subdued to the purposes of man, with +the immense advantage that, whereas the subjugation +of fire demanded ages of weary and uncertain +experiment, the mastery of electricity is, +for the most part, the assured work of the nineteenth +century, and, in truth, very largely of its +last three decades. The triumphs of the electrician<span class='pagenum'><a name="Page_126" id="Page_126">[Pg 126]</a></span> +are of absorbing interest in themselves, +they bear a higher significance to the student of +man as a creature who has gradually come to be +what he is. In tracing the new horizons won by +electric science and art, a beam of light falls on +the long and tortuous paths by which man rose +to his supremacy long before the drama of +human life had been chronicled or sung.</p> + +<p>Of the strides taken by humanity on its way +to the summit of terrestrial life, there are but +four worthy of mention as preparing the way for +the victories of the electrician—the attainment +of the upright attitude, the intentional kindling +of fire, the maturing of emotional cries to articulate +speech, and the invention of written symbols +for speech. As we examine electricity in its +fruitage we shall find that it bears the unfailing +mark of every other decisive factor of human +advance: its mastery is no mere addition to the +resources of the race, but a multiplier of them. +The case is not as when an explorer discovers a +plant hitherto unknown, such as Indian corn, +which takes its place beside rice and wheat as a +new food, and so measures a service which ends +there. Nor is it as when a prospector comes +upon a new metal, such as nickel, with the sole +effect of increasing the variety of materials from +which a smith may fashion a hammer or a blade. +Almost infinitely higher is the benefit wrought +when energy in its most useful phase is, for the +first time, subjected to the will of man, with +dawning knowledge of its unapproachable<span class='pagenum'><a name="Page_127" id="Page_127">[Pg 127]</a></span> +powers. It begins at once to marry the resources +of the mechanic and the chemist, the engineer +and the artist, with issue attested by all its own +fertility, while its rays reveal province after +province undreamed of, and indeed unexisting, +before its advent.</p> + +<p>Every other primal gift of man rises to a new +height at the bidding of the electrician. All the +deftness and skill that have followed from the +upright attitude, in its creation of the human +hand, have been brought to a new edge and a +broader range through electric art. Between the +uses of flame and electricity have sprung up +alliances which have created new wealth for the +miner and the metal-worker, the manufacturer +and the shipmaster, with new insights for the +man of research. Articulate speech borne on +electric waves makes itself heard half-way across +America, and words reduced to the symbols of +symbols—expressed in the perforations of a strip +of paper—take flight through a telegraph wire +at twenty-fold the pace of speech. Because the +latest leap in knowledge and faculty has been +won by the electrician, he has widened the scientific +outlook vastly more than any explorer who +went before. Beyond any predecessor, he began +with a better equipment and a larger capital to +prove the gainfulness which ever attends the +exploiting a supreme agent of discovery.</p> + +<p>As we trace a few of the unending interlacements +of electrical science and art with other +sciences and arts, and study their mutually<span class='pagenum'><a name="Page_128" id="Page_128">[Pg 128]</a></span> +stimulating effects, we shall be reminded of a +series of permutations where the latest of the +factors, because latest, multiplies all prior factors +in an unexampled degree.<a name="FNanchor_5_5" id="FNanchor_5_5"></a><a href="#Footnote_5_5" class="fnanchor">[5]</a> We shall find reason +to believe that this is not merely a suggestive +analogy, but really true as a tendency, not only +with regard to man's gains by the conquest of +electricity, but also with respect to every other +signal victory which has brought him to his +present pinnacle of discernment and rule. If +this permutative principle in former advances +lay undetected, it stands forth clearly in that +latest accession to skill and interpretation which +has been ushered in by Franklin and Volta, +Faraday and Henry.</p> + +<p>Although of much less moment than the +triumphs of the electrician, the discovery of +photography ranks second in importance among +the scientific feats of the nineteenth century. +The camera is an artificial eye with almost every +power of the human retina, and with many that<span class='pagenum'><a name="Page_129" id="Page_129">[Pg 129]</a></span> +are denied to vision—however ingeniously fortified +by the lens-maker. A brief outline of +photographic history will show a parallel to the +permutative impulse so conspicuous in the progress +of electricity. At the points where the +electrician and the photographer collaborate +we shall note achievements such as only the +loftiest primal powers may evoke.</p> + +<p>A brief story of what electricity and its +necessary precursor, fire, have done and promise +to do for civilization, may have attraction in itself; +so, also, may a review, though most cursory, of +the work of the camera and all that led up to it: +for the provinces here are as wide as art and +science, and their bounds comprehend well-nigh +the entirety of human exploits. And between +the lines of this story we may read another—one +which may tell us something of the earliest +stumblings in the dawn of human faculty. +When we compare man and his next of kin, we +find between the two a great gulf, surely the +widest betwixt any allied families in nature. +Can a being of intellect, conscience, and aspiration +have sprung at any time, however remote, +from the same stock as the orang and the chimpanzee? +Since 1859, when Darwin published +his “Origin of Species,” the theory of evolution +has become so generally accepted that to-day it +is little more assailed than the doctrine of gravitation. +And yet, while the average man of intelligence +bows to the formula that all which +now exists has come from the simplest conceivable<span class='pagenum'><a name="Page_130" id="Page_130">[Pg 130]</a></span> +state of things,—a universal nebula, if you +will,—in his secret soul he makes one exception—himself. +That there is a great deal more assent +than conviction in the world is a chiding which +may come as justly from the teacher's table as +from the preacher's pulpit. Now, if we but +catch the meaning of man's mastery of electricity, +we shall have light upon his earlier steps as a fire-kindler, +and as a graver of pictures and symbols +on bone and rock. As we thus recede from civilization +to primeval savagery, the process of the +making of man may become so clear that the +arguments of Darwin shall be received with conviction, +and not with silent repulse.</p> + +<p>As we proceed to recall, one by one, the salient +chapters in the history of fire, and of the arts of +depiction that foreran the camera, we shall perceive +a truth of high significance. We shall see +that, while every new faculty has its roots deep +in older powers, and while its growth may have +been going on for age after age, yet its flowering +may be as the event of a morning. Even as our +gardens show us the century-plants, once supposed +to bloom only at the end of a hundred +years, so history, in the large, exhibits discoveries +whose harvests are gathered only after the +lapse of æons instead of years. The arts of fire +were slowly elaborated until man had produced +the crucible and the still, through which his +labours culminated in metals purified, in acids +vastly more corrosive than those of vegetation, +in glass and porcelain equally resistant to flame<span class='pagenum'><a name="Page_131" id="Page_131">[Pg 131]</a></span> +and the electric wave. These were combined in +an hour by Volta to build his cell, and in that +hour began a new era for human faculty and insight.</p> + +<p>It is commonly imagined that the progress of +humanity has been at a tolerably uniform pace. +Our review of that progress will show that here +and there in its course have been <i>leaps</i>, as radically +new forces have been brought under the +dominion of man. We of the electric revolution +are sharply marked off from our great-grandfathers, +who looked upon the cell of Volta +as a curious toy. They, in their turn, were profoundly +differenced from the men of the seventeenth +century, who had not learned that flame +could outvie the horse as a carrier, and grind +wheat better than the mill urged by the breeze. +And nothing short of an abyss stretches between +these men and their remote ancestors, who had +not found a way to warm their frosted fingers +or lengthen with lamp or candle the short, +dark days of winter.</p> + +<p>Throughout the pages of this book there will be +some recital of the victories won by the fire-maker, +the electrician, the photographer, and +many more in the peerage of experiment and +research. Underlying the sketch will appear +the significant contrast betwixt accessions of +minor and of supreme dignity. The finding a +new wood, such as that of the yew, means better +bows for the archer, stronger handles for the +tool-maker; the subjugation of a universal force<span class='pagenum'><a name="Page_132" id="Page_132">[Pg 132]</a></span> +such as fire, or electricity, stands for the exaltation +of power in every field of toil, for the creation +of a new earth for the worker, new heavens for +the thinker. As a corollary, we shall observe +that an increasing width of gap marks off the +successive stages of human progress from each +other, so that its latest stride is much the longest +and most decisive. And it will be further evident +that, while every new faculty is of age-long +derivation from older powers and ancient aptitudes, +it nevertheless comes to the birth in a +moment, as it were, and puts a strain of probably +fatal severity on those contestants who miss +the new gift by however little. We shall, therefore, +find that the principle of permutation, here +merely indicated, accounts in large measure for +three cardinal facts in the history of man: First, +his leaps forward; second, the constant accelerations +in these leaps; and third, the gap in the +record of the tribes which, in the illimitable past, +have succumbed as forces of a new edge and +sweep have become engaged in the fray.<a name="FNanchor_6_6" id="FNanchor_6_6"></a><a href="#Footnote_6_6" class="fnanchor">[6]</a></p> + +<p>The interlacements of the arts of fire and of +electricity are intimate and pervasive. While +many of the uses of flame date back to the dawn +of human skill, many more have become of new +and higher value within the last hundred years. +Fire to-day yields motive power with tenfold<span class='pagenum'><a name="Page_133" id="Page_133">[Pg 133]</a></span> +the economy of a hundred years ago, and motive +power thus derived is the main source of modern +electric currents. In metallurgy there has long +been an unwitting preparation for the advent of +the electrician, and here the services of fire within +the nineteenth century have won triumphs upon +which the later successes of electricity largely +proceed. In producing alloys, and in the singular +use of heat to effect its own banishment, +novel and radical developments have been recorded +within the past decade or two. These, +also, make easier and bolder the electrician's +tasks. The opening chapters of this book will, +therefore, bestow a glance at the principal uses +of fire as these have been revealed and applied. +This glance will make clear how fire and electricity +supplement each other with new and remarkable +gains, while in other fields, not less +important, electricity is nothing else than a +supplanter of the very force which made possible +its own discovery and impressment.</p> + +<p>[Here follow chapters which outline the chief +applications of flame and of electricity.]</p> + +<p>Let us compare electricity with its precursor, +fire, and we shall understand the revolution by +which fire is now in so many tasks supplanted by +the electric pulse which, the while, creates for itself +a thousand fields denied to flame. Copper is +an excellent thermal conductor, and yet it transmits +heat almost infinitely more slowly than it +conveys electricity. One end of a thick copper +rod ten feet long may be safely held in the hand<span class='pagenum'><a name="Page_134" id="Page_134">[Pg 134]</a></span> +while the other end is heated to redness, yet one +millionth part of this same energy, if in the form +of electricity, would traverse the rod in one +100,000,000th part of a second. Compare next +electricity with light, often the companion of +heat. Light travels in straight lines only; electricity +can go round a corner every inch for +miles, and, none the worse, yield a brilliant +beam at the end of its journey. Indirectly, +therefore, electricity enables us to conduct either +heat or light as if both were flexible pencils of +rays, and subject to but the smallest tolls in +their travel.</p> + +<p>We have remarked upon such methods as +those of the electric welder which summon intense +heat without fire, and we have glanced at +the electric lamps which shine just because combustion +is impossible through their rigid exclusion +of air. Then for a moment we paused to +look at the plating baths which have developed +themselves into a commanding rivalry with the +blaze of the smelting furnace, with the flame which +from time immemorial has filled the ladle of the +founder and moulder. Thus methods that commenced +in dismissing flame end boldly by dispossessing +heat itself. But, it may be said, this +usurping electricity usually finds its source, after +all, in combustion under a steam-boiler. True, +but mark the harnessing of Niagara, of the +Lachine Rapids near Montreal, of a thousand +streams elsewhere. In the near future motive +power of Nature's giving is to be wasted less and<span class='pagenum'><a name="Page_135" id="Page_135">[Pg 135]</a></span> +less, and perforce will more and more exclude heat +from the chain of transformations which issue +in the locomotive's flight, in the whirl of factory +and mill. Thus in some degree is allayed the +fear, never well grounded, that when the coal +fields of the globe are spent civilization must +collapse. As the electrician hears this foreboding +he recalls how much fuel is wasted in converting +heat into electricity. He looks beyond +either turbine or shaft turned by wind or tide, +and, remembering that the metal dissolved in +his battery yields at his will its full content of +energy, either as heat or electricity, he asks, +Why may not coal or forest tree, which are but +other kinds of fuel, be made to do the same?</p> + +<p>One of the earliest uses of light was a means of +communicating intelligence, and to this day the +signal lamp and the red fire of the mariner are as +useful as of old. But how much wider is the field +of electricity as it creates the telegraph and the +telephone! In the telegraph we have all that +a pencil of light could be were it as long as an +equatorial girdle and as flexible as a silken thread. +In the telephone for nearly two thousand miles +the pulsations of the speaker's voice are not only +audible, but retain their characteristic tones.</p> + +<p>In the field of mechanics electricity is decidedly +preferable to any other agent. Heat may be +transformed into motive power by a suitable +engine, but there its adaptability is at an end. +An electric current drives not only a motor, but +every machine and tool attached to the motor,<span class='pagenum'><a name="Page_136" id="Page_136">[Pg 136]</a></span> +the whole executing tasks of a delicacy and complication +new to industrial art. On an electric +railroad an identical current propels the train, +directs it by telegraph, operates its signals, provides +it with light and heat, while it stands ready +to give constant verbal communication with +any station on the line, if this be desired.</p> + +<p>In the home electricity has equal versatility, +at once promoting healthfulness, refinement +and safety. Its tiny button expels the hazardous +match as it lights a lamp which sends forth +no baleful fumes. An electric fan brings fresh +air into the house—in summer as a grateful +breeze. Simple telephones, quite effective for +their few yards of wire, give a better because a +more flexible service than speaking-tubes. Few +invalids are too feeble to whisper at the light, +portable ear of metal. Sewing-machines and +the more exigent apparatus of the kitchen and +laundry transfer their demands from flagging +human muscles to the tireless sinews of electric +motors—which ask no wages when they stand +unemployed. Similar motors already enjoy +favour in working the elevators of tall dwellings +in cities. If a householder is timid about burglars, +the electrician offers him a sleepless watchman +in the guise of an automatic alarm; if he +has a dread of fire, let him dispose on his walls an +array of thermometers that at the very inception +of a blaze will strike a gong at headquarters. +But these, after all, are matters of minor importance +in comparison with the foundations<span class='pagenum'><a name="Page_137" id="Page_137">[Pg 137]</a></span> +upon which may be reared, not a new piece of +mechanism, but a new science or a new art.</p> + +<p>In the recent swift subjugation of the territory +open alike to the chemist and the electrician, +where each advances the quicker for the other's +company, we have fresh confirmation of an old +truth—that the boundary lines which mark off +one field of science from another are purely artificial, +are set up only for temporary convenience. +The chemist has only to dig deep enough to find +that the physicist and himself occupy common +ground. “Delve from the surface of your sphere +to its heart, and at once your radius joins every +other.” Even the briefest glance at electro-chemistry +should pause to acknowledge its profound +debt to the new theories as to the bonding +of atoms to form molecules, and of the continuity +between solution and electrical dissociation. +However much these hypotheses may be modified +as more light is shed on the geometry and +the journeyings of the molecule, they have for the +time being recommended themselves as finder-thoughts +of golden value. These speculations of +the chemist carry him back perforce to the days +of his childhood. As he then joined together +his black and white bricks he found that he could +build cubes of widely different patterns. It was +in propounding a theory of molecular architecture +that Kekulé gave an impetus to a vast and +growing branch of chemical industry—that of +the synthetic production of dyes and allied compounds.<span class='pagenum'><a name="Page_138" id="Page_138">[Pg 138]</a></span></p> + +<p>It was in pure research, in paths undirected to +the market-place, that such theories have been +thought out. Let us consider electricity as an +aid to investigation conducted for its own sake. +The chief physical generalization of our time, +and of all time, the persistence of force, emerged +to view only with the dawn of electric art. +When it was observed that electricity might become +heat, light, chemical action, or mechanical +motion, that in turn any of these might produce +electricity, it was at once indicated that all these +phases of energy might differ from each other +only as the movements in circles, volutes, and +spirals of ordinary mechanism. The suggestion +was confirmed when electrical measurers were +refined to the utmost precision, and a single +quantum of energy was revealed a very Proteus +in its disguises, yet beneath these disguises nothing +but constancy itself.</p> + +<p>“There is that scattereth, and yet increaseth; +and there is that withholdeth more than is meet, +but it tendeth to poverty.” Because the geometers +of old patiently explored the properties of +the triangle, the circle, and the ellipse, simply +for pure love of truth, they laid the corner-stones +for the arts of the architect, the engineer, and the +navigator. In like manner it was the disinterested +work of investigation conducted by Ampère, +Faraday, Henry and their compeers, in ascertaining +the laws of electricity which made +possible the telegraph, the telephone, the dynamo, +and the electric furnace. The vital relations<span class='pagenum'><a name="Page_139" id="Page_139">[Pg 139]</a></span> +between pure research and economic gain have +at last worked themselves clear. It is perfectly +plain that a man who has it in him to discover +laws of matter and energy does incomparably +more for his kind than if he carried his talents +to the mint for conversion into coin. The voyage +of a Columbus may not immediately bear as +much fruit as the uncoverings of a mine prospector, +but in the long run a Columbus makes possible +the finding many mines which without him +no prospector would ever see. Therefore let the +seed-corn of knowledge be planted rather than +eaten. But in choosing between one research +and another it is impossible to foretell which may +prove the richer in its harvests; for instance, all +attempts thus far economically to oxidize carbon +for the production of electricity have failed, yet +in observations that at first seemed equally +barren have lain the hints to which we owe the +incandescent lamp and the wireless telegraph.</p> + +<p>Perhaps the most promising field of electrical +research is that of discharges at high pressures; +here the leading American investigators are +Professor John Trowbridge and Professor Elihu +Thomson. Employing a tension estimated at one +and a half millions volts, Professor Trowbridge +has produced flashes of lightning six feet in +length in atmospheric air; in a tube exhausted +to one-seventh of atmospheric pressure the +flashes extended themselves to forty feet. According +to this inquirer, the familiar rending of +trees by lightning is due to the intense heat<span class='pagenum'><a name="Page_140" id="Page_140">[Pg 140]</a></span> +developed in an instant by the electric spark; +the sudden expansion of air or steam in the +cavities of the wood causes an explosion. The +experiments of Professor Thomson confront him +with some of the seeming contradictions which +ever await the explorer of new scientific territory. +In the atmosphere an electrical discharge is +facilitated when a metallic terminal (as a lightning +rod) is shaped as a point; under oil a point +is the form least favourable to discharge. In the +same line of paradox it is observed that oil +steadily improves in its insulating effect the +higher the electrical pressure committed to its +keeping; with air as an insulator the contrary is +the fact. These and a goodly array of similar +puzzles will, without doubt, be cleared up as +students in the twentieth century pass from +the twilight of anomaly to the sunshine of ascertained +law.</p> + +<p>“Before there can be applied science there +must be science to apply,” and it is by enabling +the investigator to know nature under a fresh +aspect that electricity rises to its highest office. +The laboratory routine of ascertaining the conductivity, +polarisability, and other electrical +properties of matter is dull and exacting work, +but it opens to the student new windows through +which to peer at the architecture of matter. +That architecture, as it rises to his view, discloses +one law of structure after another; what +in a first and clouded glance seemed anomaly +is now resolved and reconciled; order displays<span class='pagenum'><a name="Page_141" id="Page_141">[Pg 141]</a></span> +itself where once anarchy alone appeared. +When the investigator now needs a substance +of peculiar properties he knows where to find it, +or has a hint for its creation—a creation perhaps +new in the history of the world. As he thinks of +the wealth of qualities possessed by his store +of alloys, salts, acids, alkalies, new uses for them +are borne into his mind. Yet more—a new +orchestration of inquiry is possible by means of +the instruments created for him by the electrician, +through the advances in method which these +instruments effect. With a second and more +intimate point of view arrives a new trigonometry +of the particle, a trigonometry inconceivable +in pre-electric days. Hence a surround is in +progress which early in the twentieth century +may go full circle, making atom and molecule as +obedient to the chemist as brick and stone are +to the builder now.</p> + +<p>The laboratory investigator and the commercial +exploiter of his discoveries have been by +turns borrower and lender, to the great profit of +both. What Leyden jar could ever be constructed +of the size and revealing power of an +Atlantic cable? And how many refinements +of measurement, of purification of metals, of +precision in manufacture, have been imposed +by the colossal investments in deep-sea telegraphy +alone! When a current admitted to an ocean +cable, such as that between Brest and New York, +can choose for its path either 3,540 miles of copper +wire or a quarter of an inch of gutta-percha,<span class='pagenum'><a name="Page_142" id="Page_142">[Pg 142]</a></span> +there is a dangerous opportunity for escape into +the sea, unless the current is of nicely adjusted +strength, and the insulator has been made and +laid with the best-informed skill, the most conscientious +care. In the constant tests required +in laying the first cables Lord Kelvin (then +Professor William Thomson) felt the need for +better designed and more sensitive galvanometers +or current measurers. His great skill +both as a mathematician and a mechanician +created the existing instruments, which seem +beyond improvement. They serve not only in +commerce and manufacture, but in promoting +the strictly scientific work of the laboratory. +Now that electricity purifies copper as fire cannot, +the mathematician is able to treat his problems +of long-distance transmission, of traction, +of machine design, with an economy and certainty +impossible when his materials were not +simply impure, but impure in varying and indefinite +degrees. The factory and the workshop +originally took their magneto-machines +from the experimental laboratory; they have returned +them remodelled beyond recognition as +dynamos and motors of almost ideal effectiveness.</p> + +<p>A galvanometer actuated by a thermo-electric +pile furnishes much the most sensitive means +of detecting changes of temperature; hence electricity +enables the physicist to study the phenomena +of heat with new ease and precision. It +was thus that Professor Tyndall conducted the<span class='pagenum'><a name="Page_143" id="Page_143">[Pg 143]</a></span> +classical researches set forth in his “Heat as a +Mode of Motion,” ascertaining the singular +power to absorb terrestrial heat which makes the +aqueous vapours of the atmosphere act as an +indispensable blanket to the earth.</p> + +<p>And how vastly has electricity, whether in the +workshop or laboratory, enlarged our conceptions +of the forces that thrill space, of the substances, +seemingly so simple, that surround us—substances +that propound questions of structure +and behaviour that silence the acutest investigator. +“You ask me,” said a great physicist, “if +I have a theory of the <i>universe</i>? Why, I haven't +even a theory of <i>magnetism</i>!”</p> + +<p>The conventional phrase “conducting a current” +is now understood to be mere figure of +speech; it is thought that a wire does little else +than give direction to electric energy. Pulsations +of high tension have been proved to be +mainly superficial in their journeys, so that they +are best conveyed (or convoyed) by conductors +of tubular form. And what is it that moves when +we speak of conduction? It seems to be now +the molecule of atomic chemistry, and anon the +same ether that undulates with light or radiant +heat. Indeed, the conquest of electricity means +so much because it impresses the molecule and +the ether into service as its vehicles of communication. +Instead of the old-time masses of metal, +or bands of leather, which moved stiffly through +ranges comparatively short, there is to-day employed +a medium which may traverse 186,400<span class='pagenum'><a name="Page_144" id="Page_144">[Pg 144]</a></span> +miles in a second, and with resistances most +trivial in contrast with those of mechanical +friction.</p> + +<p>And what is friction in the last analysis but +the production of motion in undesired forms, the +allowing valuable energy to do useless work? +In that amazing case of long distance transmission, +common sunshine, a solar beam arrives at +the earth from the sun not one whit the weaker +for its excursion of 92,000,000 miles. It is +highly probable that we are surrounded by +similar cases of the total absence of friction in +the phenomena of both physics and chemistry, +and that art will come nearer and nearer to +nature in this immunity is assured when we see +how many steps in that direction have already +been taken by the electrical engineer. In a +preceding page a brief account was given of the +theory that gases and vapours are in ceaseless +motion. This motion suffers no abatement from +friction, and hence we may infer that the molecules +concerned are perfectly elastic. The +opinion is gaining ground among physicists that +all the properties of matter, transparency, +chemical combinability, and the rest, are due to +immanent motion in particular orbits, with +diverse velocities. If this be established, then +these motions also suffer no friction, and go on +without resistance forever.</p> + +<p>As the investigators in the vanguard of science +discuss the constitution of matter, and weave +hypotheses more or less fruitful as to the interplay<span class='pagenum'><a name="Page_145" id="Page_145">[Pg 145]</a></span> +of its forces, there is a growing faith that +the day is at hand when the tie between electricity +and gravitation will be unveiled—when the +reason why matter has weight will cease to puzzle +the thinker. Who can tell what relief of +man's estate may be bound up with the ability +to transform any phase of energy into any other +without the circuitous methods and serious losses +of to-day! In the sphere of economic progress +one of the supreme advances was due to the invention +of money, the providing a medium for +which any salable thing may be exchanged, +with which any purchasable thing may be +bought. As soon as a shell, or a hide, or a bit of +metal was recognized as having universal convertibility, +all the delays and discounts of barter +were at an end. In the world of physics and +chemistry the corresponding medium is electricity; +let it be produced as readily as it produces +other modes of motion, and human art +will take a stride forward such as when Volta +disposed his zinc and silver discs together, or +when Faraday set a magnet moving around a +copper wire.</p> + +<p>For all that the electric current is not as yet +produced as economically as it should be, we do +wrong if we regard it as an infant force. However +much new knowledge may do with electricity +in the laboratory, in the factory, or in the +exchange, some of its best work is already done. +It is not likely ever to perform a greater feat +than placing all mankind within ear-shot of each<span class='pagenum'><a name="Page_146" id="Page_146">[Pg 146]</a></span> +other. Were electricity unmastered there could +be no democratic government of the United +States. To-day the drama of national affairs +is more directly in view of every American citizen +than, a century ago, the public business of Delaware +could be to the men of that little State. +And when on the broader stage of international +politics misunderstandings arise, let us note how +the telegraph has modified the hard-and-fast +rules of old-time diplomacy. To-day, through +the columns of the press, the facts in controversy +are instantly published throughout the world, +and thus so speedily give rise to authoritative +comment that a severe strain is put upon negotiators +whose tradition it is to be both secret and +slow.</p> + +<p>Railroads, with all they mean for civilization, +could not have extended themselves without the +telegraph to control them. And railroads and +telegraphs are the sinews and nerves of national +life, the prime agencies in welding the diverse +and widely separated States and Territories of +the Union. A Boston merchant builds a cotton-mill +in Georgia; a New York capitalist opens a +copper-mine in Arizona. The telegraph which +informs them day by day how their investments +prosper tells idle men where they can find work, +where work can seek idle men. Chicago is laid +in ashes, Charleston topples in earthquake, +Johnstown is whelmed in flood, and instantly +a continent springs to their relief. And what +benefits issue in the strictly commercial uses of<span class='pagenum'><a name="Page_147" id="Page_147">[Pg 147]</a></span> +the telegraph! At its click both locomotive and +steamship speed to the relief of famine in any +quarter of the globe. In times of plenty or of +dearth the markets of the globe are merged +and are brought to every man's door. Not less +striking is the neighbourhood guild of science, +born, too, of the telegraph. The day after Röntgen +announced his X rays, physicists on every +continent were repeating his experiments—were +applying his discovery to the healing of the +wounded and diseased. Let an anti-toxin for +diphtheria, consumption, or yellow fever be proposed, +and a hundred investigators the world +over bend their skill to confirm or disprove, as if +the suggester dwelt next door.</p> + +<p>On a stage less dramatic, or rather not dramatic +at all, electricity works equal good. Its motor +freeing us from dependence on the horse is +spreading our towns and cities into their adjoining +country. Field and garden compete with airless +streets. The sunny cottage is in active rivalry +with the odious tenement-house. It is found +that transportation within the gates of a metropolis +has an importance second only to the means +of transit which links one city with another. +The engineer is at last filling the gap which too +long existed between the traction of horses and +that of steam. In point of speed, cleanliness, +and comfort such an electric subway as that of +South London leaves nothing to be desired. +Throughout America electric roads, at first suburban, +are now fast joining town to town and<span class='pagenum'><a name="Page_148" id="Page_148">[Pg 148]</a></span> +city to city, while, as auxiliaries to steam railroads, +they place sparsely settled communities +in the arterial current of the world, and build up +a ready market for the dairyman and the fruit-grower. +In its saving of what Mr. Oscar T. +Crosby has called “man-hours” the third-rail +system is beginning to oust steam as a motive +power from trunk-lines. Already shrewd railroad +managers are granting partnerships to the +electricians who might otherwise encroach upon +their dividends. A service at first restricted to +passengers has now extended itself to the carriage +of letters and parcels, and begins to reach out for +common freight. We may soon see the farmer's +cry for good roads satisfied by good electric lines +that will take his crops to market much more +cheaply and quickly than horses and macadam +ever did. In cities, electromobile cabs and vans +steadily increase in numbers, furthering the quiet +and cleanliness introduced by the trolley car.</p> + +<p>A word has been said about the blessings which +electricity promises to country folk, yet greater +are the boons it stands ready to bestow in the +hives of population. Until a few decades ago +the water-supply of cities was a matter not of +municipal but of individual enterprise; water +was drawn in large part from wells here and +there, from lines of piping laid in favoured localities, +and always insufficient. Many an epidemic +of typhoid fever was due to the contamination of +a spring by a cesspool a few yards away. To-day +a supply such as that of New York is abundant<span class='pagenum'><a name="Page_149" id="Page_149">[Pg 149]</a></span> +and cheap because it enters every house. Let a +centralized electrical service enjoy a like privilege, +and it will offer a current which is heat, +light, chemical energy, or motive power, and all +at a wage lower than that of any other servant. +Unwittingly, then, the electrical engineer is a +political reformer of high degree, for he puts a +new premium upon ability and justice at the +City Hall. His sole condition is that electricity +shall be under control at once competent and +honest. Let us hope that his plea, joined to +others as weighty, may quicken the spirit of civic +righteousness so that some of the richest fruits +ever borne in the garden of science and art may +not be proffered in vain. Flame, the old-time +servant, is individual; electricity, its successor +and heir, is collective. Flame sits upon the +hearth and draws a family together; electricity, +welling from a public source, may bind into a +unit all the families of a vast city, because it +makes the benefit of each the interest of all.</p> + +<p>But not every promise brought forward in +the name of the electrician has his assent or +sanction. So much has been done by electricity, +and so much more is plainly feasible, that a reflection +of its triumphs has gilded many a baseless +dream. One of these is that the cheap electric +motor, by supply power at home, will break up +the factory system, and bring back the domestic +manufacturing of old days. But if this power +cost nothing at all the gift would leave the +factory unassailed; for we must remember that<span class='pagenum'><a name="Page_150" id="Page_150">[Pg 150]</a></span> +power is being steadily reduced in cost from +year to year, so that in many industries it has +but a minor place among the expenses of production. +The strength and profit of the factory +system lie in its assembling a wide variety of +machines, the first delivering its product to the +second for another step toward completion, and +so on until a finished article is sent to the ware-room. +It is this minute subdivision of labour, +together with the saving and efficiency that +inure to a business conducted on an immense +scale under a single manager, that bids us believe +that the factory has come to stay. To be +sure, a weaver, a potter, or a lens-grinder of +peculiar skill may thrive at his loom or wheel at +home; but such a man is far from typical in +modern manufacture. Besides, it is very questionable +whether the lamentations over the home +industries of the past do not ignore evil concomitants +such as still linger in the home industries +of the present—those of the sweater's +den, for example.</p> + +<p>This rapid survey of what electricity has done +and may yet do—futile expectation dismissed—has +shown it the creator of a thousand material +resources, the perfector of that communication +of things, of power, of thought, which in every +prior stage of advancement has marked the successive +lifts of humanity. It was much when +the savage loaded a pack upon a horse or an ox +instead of upon his own back; it was yet more +when he could make a beacon-flare give news or<span class='pagenum'><a name="Page_151" id="Page_151">[Pg 151]</a></span> +warning to a whole country-side, instead of being +limited to the messages which might be read +in his waving hands. All that the modern engineer +was able to do with steam for locomotion +is raised to a higher plane by the advent of his +new power, while the long-distance transmission +of electrical energy is contracting the dimensions +of the planet to a scale upon which its cataracts +in the wilderness drive the spindles and looms of +the factory town, or illuminate the thoroughfares +of cities. Beyond and above all such services as +these, electricity is the corner-stone of physical +generalization, a revealer of truths impenetrable +by any other ray.</p> + +<p>The subjugation of fire has done much in giving +man a new independence of nature, a mighty +armoury against evil. In curtailing the most +arduous and brutalizing forms of toil, electricity, +that subtler kind of fire, carries this emancipation +a long step further, and, meanwhile, bestows +upon the poor many a luxury which but +lately was the exclusive possession of the rich. +In more closely binding up the good of the bee +with the welfare of the hive, it is an educator and +confirmer of every social bond. In so far as it +proffers new help in the war on pain and disease +it strengthens the confidence of man in an Order +of Right and Happiness which for so many dreary +ages has been a matter rather of hope than of +vision. Are we not, then, justified in holding +electricity to be a multiplier of faculty and insight, +a means of dignifying mind and soul, unexampled<span class='pagenum'><a name="Page_152" id="Page_152">[Pg 152]</a></span> +since man first kindled fire and rejoiced?</p> + +<p>We have traced how dexterity rose to fire-making, +how fire-making led to the subjugation +of electricity. Much of the most telling work +of fire can be better done by its great successor, +while electricity performs many tasks possible +only to itself. Unwitting truth there was in the +simple fable of the captive who let down a +spider's film, that drew up a thread, which in turn +brought up a rope—and freedom. It was in 1800 +on the threshold of the nineteenth century, that +Volta devised the first electric battery. In a +hundred years the force then liberated has vitally +interwoven itself with every art and science, +bearing fruit not to be imagined even by men of +the stature of Watt, Lavoisier, or Humboldt. +Compare this rapid march of conquest with the +slow adaptation, through age after age, of fire to +cooking, smelting, tempering. Yet it was partly, +perhaps mainly, because the use of fire had drawn +out man's intelligence and cultivated his skill +that he was ready in the fulness of time so quickly +to seize upon electricity and subdue it.</p> + +<p>Electricity is as legitimately the offspring of +fire as fire of the simple knack in which one +savage in ten thousand was richer than his fellows. +The principle of permutation, suggested +in both victories, interprets not only how vast +empire is won by a new weapon of prime dignity; +it explains why such empires are brought under +rule with ever-accelerated pace. Every talent<span class='pagenum'><a name="Page_153" id="Page_153">[Pg 153]</a></span> +only pioneers the way for the richer talents which +are born from it.</p> + + +<div class="footnotes"><h3>FOOTNOTES:</h3> + +<div class="footnote"><p><a name="Footnote_5_5" id="Footnote_5_5"></a><a href="#FNanchor_5_5"><span class="label">[5]</span></a> Permutations are the various ways in which two or +more different things may be arranged in a row, all the things +appearing in each row. Permutations are readily illustrated +with squares or cubes of different colours, with numbers, +or letters. +</p><p> +Permutations of two elements, 1 and 2, are (1 x 2) two; +1, 2; 2, 1; or <i>a</i>, <i>b</i>; <i>b</i>, <i>a</i>. Of three elements the permutations +are (1 x 2 x 3) six; 1, 2, 3; 1, 3, 2; 2, 1, 3; 2, 3, 1; 3, 1, 2; 3, 2, 1; +or <i>a</i>, <i>b</i>, <i>c</i>; <i>a</i>, <i>c</i>, <i>b</i>; <i>b</i>, <i>a</i>, <i>c</i>; <i>b</i>, <i>c</i>, <i>a</i>; <i>c</i>, <i>a</i>, <i>b</i>; <i>c</i>, <i>b</i>, <i>a</i>. Of four elements +the permutations are (1 x 2 x 3 x 4) twenty-four; +of five elements, one hundred and twenty, and so on. A +new element or permutator multiplies by an increasing +figure all the permutations it finds.</p></div> + +<div class="footnote"><p><a name="Footnote_6_6" id="Footnote_6_6"></a><a href="#FNanchor_6_6"><span class="label">[6]</span></a> Some years ago I sent an outline of this argument to +Herbert Spencer, who replied: “I recognize a novelty and +value in your inference that the law implies an increasing +width of gap between lower and higher types as evolution +advances.”</p></div> +</div> + + +<h2><a name="COUNT_RUMFORD_IDENTIFIES_HEAT" id="COUNT_RUMFORD_IDENTIFIES_HEAT"></a>COUNT RUMFORD IDENTIFIES HEAT +WITH MOTION.</h2> +<p><span class='pagenum'><a name="Page_155" id="Page_155">[Pg 155]</a></span></p> +<span class="totoc"><a href="#toc">Top</a></span> + +<div class="noteb"><p>[Benjamin Thompson, who received the title of Count +Rumford from the Elector of Bavaria, was born in Woburn, +Massachusetts, in 1753. When thirty-one years of age +he settled in Munich, where he devoted his remarkable +abilities to the public service. Twelve years afterward +he removed to England; in 1800 he founded the Royal +Institution of London, since famous as the theatre of the +labours of Davy, Faraday, Tyndall, and Dewar. He bequeathed +to Harvard University a fund to endow a professorship +of the application of science to the art of living: +he instituted a prize to be awarded by the American Academy +of Sciences for the most important discoveries and +improvements relating to heat and light. In 1804 he married +the widow of the illustrious chemist Lavoisier: he died in +1814. Count Rumford on January 25, 1798, read a paper +before the Royal Society entitled “An Enquiry Concerning +the Source of Heat Which Is Excited by Friction.” The +experiments therein detailed proved that heat is identical +with motion, as against the notion that heat is matter. He +thus laid the corner-stone of the modern theory that heat +light, electricity, magnetism, chemical action, and all other +forms of energy are in essence motion, are convertible into +one another, and as motion are indestructible. The following +abstract of Count Rumford's paper is taken from “Heat +as a Mode of Motion,” by Professor John Tyndall, published +by D. Appleton & Co., New York. This work and “The +Correlation and Conservation of Forces,” edited by Dr. +E. L. Youmans, published by the same house, will serve as +a capital introduction to the modern theory that energy +is motion which, however varied in its forms, is changeless +in its quantity.]</p></div> + +<p><span class='pagenum'><a name="Page_156" id="Page_156">[Pg 156]</a></span>Being engaged in superintending the boring +of cannon in the workshops of the military arsenal +at Munich, Count Rumford was struck with the +very considerable degree of heat which a brass +gun acquires, in a short time, in being bored, +and with the still more intense heat (much +greater than that of boiling water) of the metallic +chips separated from it by the borer, he proposed +to himself the following questions:</p> + +<p>“Whence comes the heat actually produced +in the mechanical operations above mentioned?</p> + +<p>“Is it furnished by the metallic chips which +are separated from the metal?”</p> + +<p>If this were the case, then the <i>capacity for heat</i> +of the parts of the metal so reduced to chips +ought not only to be changed, but the change +undergone by them should be sufficiently great +to account for <i>all</i> the heat produced. No such +change, however, had taken place, for the chips +were found to have the same capacity as slices +of the same metal cut by a fine saw, where heating +was avoided. Hence, it is evident, that the +heat produced could not possibly have been +furnished at the expense of the latent heat of the +metallic chips. Rumford describes these experiments +at length, and they are conclusive.</p> + +<p>He then designed a cylinder for the express +purpose of generating heat by friction, by having +a blunt borer forced against its solid bottom, +while the cylinder was turned around its axis by +the force of horses. To measure the heat developed, +a small round hole was bored in the<span class='pagenum'><a name="Page_157" id="Page_157">[Pg 157]</a></span> +cylinder for the purpose of introducing a small +mercurial thermometer. The weight of the +cylinder was 113.13 pounds avoirdupois.</p> + +<p>The borer was a flat piece of hardened steel, +0.63 of an inch thick, four inches long, and nearly +as wide as the cavity of the bore of the cylinder, +namely, three and one-half inches. The area +of the surface by which its end was in contact +with the bottom of the bore was nearly two and +one-half inches. At the beginning of the experiment +the temperature of the air in the shade, +and also that of the cylinder, was 60° Fahr. At +the end of thirty minutes, and after the cylinder +had made 960 revolutions round its axis, the +temperature was found to be 130°.</p> + +<p>Having taken away the borer, he now removed +the metallic dust, or rather scaly matter, which +had been detached from the bottom of the cylinder +by the blunt steel borer, and found its weight +to be 837 grains troy. “Is it possible,” he exclaims, +“that the very considerable quantity of +heat produced in this experiment—a quantity +which actually raised the temperature of above +113 pounds of gun-metal at least 70° of Fahrenheit's +thermometer—could have been furnished +by so inconsiderable a quantity of metallic dust +and this merely in consequence of a <i>change</i> in its +capacity of heat?”</p> + +<p>“But without insisting on the improbability of +this supposition, we have only to recollect that +from the results of actual and decisive experiments, +made for the express purpose of ascertaining<span class='pagenum'><a name="Page_158" id="Page_158">[Pg 158]</a></span> +that fact, the capacity for heat for +the metal of which great guns are cast is <i>not +sensibly changed</i> by being reduced to the form of +metallic chips, and there does not seem to be any +reason to think that it can be much changed, +if it be changed at all, in being reduced to +much smaller pieces by a borer which is less +sharp.”</p> + +<p>He next surrounded his cylinder by an oblong +deal-box, in such a manner that the cylinder +could turn water-tight in the centre of the box, +while the borer was pressed against the bottom +of the cylinder. The box was filled with water +until the entire cylinder was covered, and then +the apparatus was set in action. The temperature +of the water on commencing was 60°.</p> + +<p>“The result of this beautiful experiment,” +writes Rumford, “was very striking, and the +pleasure it afforded me amply repaid me for all +the trouble I had had in contriving and arranging +the complicated machinery used in making it. +The cylinder had been in motion but a short time, +when I perceived, by putting my hand into the +water, and touching the outside of the cylinder, +that heat was generated.</p> + +<p>“At the end of one hour the fluid, which +weighed 18.77 pounds, or two and one-half +gallons, had its temperature raised forty-seven +degrees, being now 107°.</p> + +<p>“In thirty minutes more, or one hour and +thirty minutes after the machinery had been set +in motion, the heat of the water was 142°.<span class='pagenum'><a name="Page_159" id="Page_159">[Pg 159]</a></span></p> + +<p>“At the end of two hours from the beginning, +the temperature was 178°.</p> + +<p>“At two hours and twenty minutes it was 200°, +and at two hours and thirty minutes it <i>actually +boiled</i>!”</p> + +<p>“It would be difficult to describe the surprise +and astonishment expressed in the countenances +of the bystanders on seeing so large a quantity +of water heated, and actually made to boil, +without any fire. Though, there was nothing +that could be considered very surprising in this +matter, yet I acknowledge fairly that it afforded +me a degree of childish pleasure which, were I +ambitious of the reputation of a grave philosopher, +I ought most certainly rather to hide than +to discover.”</p> + +<p>He then carefully estimates the quantity of +heat possessed by each portion of his apparatus +at the conclusion of the experiment, and, adding +all together, finds a total sufficient to raise 26.58 +pounds of ice-cold water to its boiling point, or +through 180° Fahrenheit. By careful calculation, +he finds this heat equal to that given out by +the combustion of 2,303.8 grains (equal to four +and eight-tenths ounces troy) of wax.</p> + +<p>He then determines the “<i>celerity</i>” with which +the heat was generated, summing up thus: +“From the results of these computations, it appears +that the quantity of heat produced equably, +or in a continuous stream, if I may use the expression, +by the friction of the blunt steel borer +against the bottom of the hollow metallic cylinder,<span class='pagenum'><a name="Page_160" id="Page_160">[Pg 160]</a></span> +was <i>greater</i> than that produced in the combustion +of nine <i>wax-candles</i>, each three-quarters +of an inch in diameter, all burning together with +clear bright flames.</p> + +<p>“One horse would have been equal to the +work performed, though two were actually employed. +Heat may thus be produced merely +by the strength of a horse, and, in a case of necessity, +this heat might be used in cooking +victuals. But no circumstances could be imagined +in which this method of procuring heat +would be advantageous, for more heat might +be obtained by using the fodder necessary +for the support of a horse as fuel.”</p> + +<p>[This is an extremely significant passage, intimating +as it does, that Rumford saw clearly +that the force of animals was derived from the +food; <i>no creation of force</i> taking place in the +animal body.]</p> + +<p>“By meditating on the results of all these experiments, +we are naturally brought to that great +question which has so often been the subject of +speculation among philosophers, namely, What +is heat—is there any such thing as an <i>igneous +fluid</i>? Is there anything that, with propriety, +can be called caloric?</p> + +<p>“We have seen that a very considerable quantity +of heat may be excited by the friction of +two metallic surfaces, and given off in a constant +stream or flux <i>in all directions</i>, without interruption +or intermission, and without any signs of +<i>diminution</i> or <i>exhaustion</i>. In reasoning on this<span class='pagenum'><a name="Page_161" id="Page_161">[Pg 161]</a></span> +subject we must not forget <i>that most remarkable +circumstance</i>, that the source of the heat generated +by friction in these experiments appeared +evidently to be <i>inexhaustible</i>. [The italics are +Rumford's.] It is hardly necessary to add, that +anything which any <i>insulated</i> body or system of +bodies can continue to furnish <i>without limitation</i> +cannot possibly be a <i>material substance</i>; and it +appears to me to be extremely difficult, if not +quite impossible, to form any distinct idea of anything +capable of being excited and communicated +in those experiments, except it be <span class="smcap">Motion</span>.”</p> + +<p>When the history of the dynamical theory +of heat is written, the man who, in opposition to +the scientific belief of his time, could experiment +and reason upon experiment, as Rumford did +in the investigation here referred to, cannot be +lightly passed over. Hardly anything more +powerful against the materiality of heat has been +since adduced, hardly anything more conclusive +in the way of establishing that heat is, what +Rumford considered it to be, <i>Motion</i>.</p> + + +<h2><a name="VICTORY_OF_THE_ROCKET_LOCOMOTIVE" id="VICTORY_OF_THE_ROCKET_LOCOMOTIVE"></a>VICTORY OF THE “ROCKET” LOCOMOTIVE.</h2> +<p><span class='pagenum'><a name="Page_163" id="Page_163">[Pg 163]</a></span></p> +<span class="totoc"><a href="#toc">Top</a></span> + +<div class="noteb"><p>[Part of Chapter XII. Part II, of “The Life of George +Stephenson and of His Son, Robert Stephenson,” by +Samuel Smiles New York, Harper & Brothers, 1868.]</p></div> + + +<p>The works of the Liverpool and Manchester +Railway were now approaching completion. +But, strange to say, the directors had not yet +decided as to the tractive power to be employed +in working the line when open for traffic. The +differences of opinion among them were so great +as apparently to be irreconcilable. It was +necessary, however, that they should, come to +some decision without further loss of time, and +many board meetings were accordingly held to +discuss the subject. The old-fashioned and +well-tried system of horse-haulage was not without +its advocates; but, looking at the large +amount of traffic which there was to be conveyed, +and at the probable delay in the transit +from station to station if this method were +adopted, the directors, after a visit made by them +to the Northumberland and Durham railways +in 1828, came to the conclusion that the employment +of horse-power was inadmissible.</p> + +<p>Fixed engines had many advocates; the locomotive +very few: it stood as yet almost in a +minority of one—George Stephenson....<span class='pagenum'><a name="Page_164" id="Page_164">[Pg 164]</a></span></p> + +<p>In the meantime the discussion proceeded as +to the kind of power to be permanently employed +for the working of the railway. The directors +were inundated with schemes of all sorts for +facilitating locomotion. The projectors of England, +France, and America seemed to be let loose +upon them. There were plans for working the +waggons along the line by water-power. Some +proposed hydrogen, and others carbonic acid gas. +Atmospheric pressure had its eager advocates. +And various kinds of fixed and locomotive steam-power +were suggested. Thomas Gray urged +his plan of a greased road with cog-rails; and +Messrs. Vignolles and Ericsson recommended the +adoption of a central friction-rail, against which +two horizontal rollers under the locomotive, +pressing upon the sides of this rail, were to afford +the means of ascending the inclined planes....</p> + +<p>The two best practical engineers of the day +concurred in reporting substantially in favour +of the employment of fixed engines. Not a +single professional man of eminence could be +found to coincide with the engineer of the railway +in his preference for locomotive over fixed engine +power. He had scarcely a supporter, and the +locomotive system seemed on the eve of being +abandoned. Still he did not despair. With the +profession against him, and public opinion against +him—for the most frightful stories went abroad +respecting the dangers, the unsightliness, and +the nuisance which the locomotive would create—Stephenson +held to his purpose. Even in<span class='pagenum'><a name="Page_165" id="Page_165">[Pg 165]</a></span> +this, apparently the darkest hour of the locomotive, +he did not hesitate to declare that locomotive +railroads would, before many years had +passed, be “the great highways of the world.”</p> + +<p>He urged his views upon the directors in all +ways, in season, and, as some of them thought, +out of season. He pointed out the greater convenience +of locomotive power for the purposes of +a public highway, likening it to a series of short +unconnected chains, any one of which could be +removed and another substituted without interruption +to the traffic; whereas the fixed-engine +system might be regarded in the light of a continuous +chain extending between the two termini, +the failure of any link of which would derange +the whole. But the fixed engine party was very +strong at the board, and, led by Mr. Cropper, +they urged the propriety of forthwith adopting +the report of Messrs. Walker and Rastrick. Mr. +Sandars and Mr. William Rathbone, on the other +hand, desired that a fair trial should be given to +the locomotive; and they with reason objected +to the expenditure of the large capital necessary +to construct the proposed engine-houses, with +their fixed engines, ropes, and machinery, until +they had tested the powers of the locomotive +as recommended by their own engineer. George +Stephenson continued to urge upon them that +the locomotive was yet capable of great improvements, +if proper inducements were held out +to inventors and machinists to make them; +and he pledged himself that, if time were given<span class='pagenum'><a name="Page_166" id="Page_166">[Pg 166]</a></span> +him, he would construct an engine that should +satisfy their requirements, and prove itself capable +of working heavy loads along the railway +with speed, regularity, and safety. At length, +influenced by his persistent earnestness not less +than by his arguments, the directors, at the suggestion +of Mr. Harrison, determined to offer a +prize of £500 for the best locomotive engine, +which, on a certain day, should be produced on +the railway, and perform certain specified conditions +in the most satisfactory manner.<a name="FNanchor_7_7" id="FNanchor_7_7"></a><a href="#Footnote_7_7" class="fnanchor">[7]</a></p> + +<p>The requirements of the directors as to speed +were not excessive. All that they asked for was +that ten miles an hour should be maintained. +Perhaps they had in mind the animadversions of +the <i>Quarterly Review</i> on the absurdity of travelling<span class='pagenum'><a name="Page_167" id="Page_167">[Pg 167]</a></span> +at a greater velocity, and also the remarks +published by Mr. Nicholas Wood, whom they +selected to be one of the judges of the competition, +in conjunction, with Mr. Rastrick, of Stourbridge, +and Mr. Kennedy, of Manchester.</p> + +<p>It was now felt that the fate of railways in a +great measure depended upon the issue of this +appeal to the mechanical genius of England. +When the advertisement of the prize for the best +locomotive was published, scientific men began +more particularly to direct their attention to the +new power which was thus struggling into existence. +In the meantime public opinion on +the subject of railway working remained suspended, +and the progress of the undertaking +was watched with intense interest.</p> + +<p>During the progress of this important controversy +with reference to the kind of power to be employed<span class='pagenum'><a name="Page_168" id="Page_168">[Pg 168]</a></span> +in working the railway, George Stephenson +was in constant communication with his son +Robert, who made frequent visits to Liverpool +for the purpose of assisting his father in the +preparation of his reports to the board on the +subject. Mr. Swanwick remembers the vivid interest +of the evening discussions which then took +place between father and son as to the best mode +of increasing the powers and perfecting the +mechanism of the locomotive. He wondered +at their quick perception and rapid judgment on +each other's suggestions; at the mechanical difficulties +which they anticipated and provided for +in the practical arrangement of the machine; and +he speaks of these evenings as most interesting +displays of two actively ingenious and able minds +stimulating each other to feats of mechanical +invention, by which it was ordained that the +locomotive engine should become what it now is. +These discussions became more frequent, and +still more interesting, after the public prize had +been offered for the best locomotive by the +directors of the railway, and the working plans +of the engine which they proposed to construct +had to be settled.</p> + +<p>One of the most important considerations in +the new engine was the arrangement of the boiler, +and the extension of its heating surface to enable +steam enough to be raised rapidly and continuously +for the purpose of maintaining high rates of +speed—the effect of high pressure engines being +ascertained to depend mainly upon the quantity<span class='pagenum'><a name="Page_169" id="Page_169">[Pg 169]</a></span> +of steam which the boiler can generate, and +upon its degree of elasticity when produced. +The quantity of steam so generated, it will be +obvious, must chiefly depend upon the quantity +of fuel consumed in the furnace, and, by necessary +consequence, upon the high rate of temperature +maintained there.</p> + +<p>It will be remembered that in Stephenson's +first Killingworth engines he invited and applied +the ingenious method of stimulating combustion +in the furnace by throwing the waste steam into +the chimney after performing its office in the +cylinders, thereby accelerating the ascent of the +current of air, greatly increasing the draught, +and consequently the temperature of the fire. +This plan was adopted by him, as we have seen, +as early as 1815, and it was so successful that he +himself attributed to it the greater economy of +the locomotive as compared with horse-power. +Hence the continuance of its use upon the Killingworth +Railway.</p> + +<p>Though the adoption of the steam blast greatly +quickened combustion and contributed to the +rapid production of high-pressure steam, the +limited amount of heating surface presented to +the fire was still felt to be an obstacle to the complete +success of the locomotive engine. Mr. +Stephenson endeavoured to overcome this by +lengthening the boilers and increasing the surface +presented by the flue-tubes. The “Lancashire +Witch,” which he built for the Bolton and +Leigh Railway, and used in forming the Liverpool<span class='pagenum'><a name="Page_170" id="Page_170">[Pg 170]</a></span> +and Manchester Railway embankments, was +constructed with a double tube, each of which +contained a fire, and passed longitudinally +through the boiler. But this arrangement +necessarily led to a considerable increase in the +weight of those engines, which amounted to +about twelve tons each; and as six tons was +the limit allowed for engines admitted to the +Liverpool competition, it was clear that the +time was come when the Killingworth engine +must undergo a farther important modification.</p> + +<p>For many years previous to this period, ingenious +mechanics had been engaged in attempting +to solve the problem of the best and most +economical boiler for the production of high-pressure +steam.</p> + +<p>The use of tubes in boilers for increasing the +heating surface had long been known. As early +as 1780, Matthew Boulton employed copper +tubes longitudinally in the boiler of the Wheal +Busy engine in Cornwall—the fire passing +<i>through</i> the tubes—and it was found that the +production of steam was thereby considerably +increased. The use of tubular boilers afterwards +became common in Cornwall. In 1803, Woolf, +the Cornish engineer, patented a boiler with +tubes, with the same object of increasing the +heating surface. The water was <i>inside</i> the tubes, +and the fire of the boiler outside. Similar expedients +were proposed by other inventors. In +1815 Trevithick invented his light high-pressure +boiler for portable purposes, in which, to “expose<span class='pagenum'><a name="Page_171" id="Page_171">[Pg 171]</a></span> +a large surface to the fire,” he constructed the +boiler of a number of small perpendicular tubes +“opening into a common reservoir at the top.” +In 1823 W. H. James contrived a boiler composed +of a series of annular wrought-iron tubes, +placed side by side and bolted together, so as to +form by their union a long cylindrical boiler, in +the centre of which, at the end, the fireplace was +situated. The fire played round the tubes, which +contained the water. In 1826 James Neville +took out a patent for a boiler with vertical tubes +surrounded by the water, through which the +heated air of the furnace passed, explaining also +in his specification that the tubes might be horizontal +or inclined, according to circumstances. +Mr. Goldsworthy, the persevering adaptor of +steam-carriages to travelling on common roads, +applied the tubular principle in the boiler of his +engine, in which the steam was generated <i>within</i> +the tubes; while the boiler invented by Messrs. +Summer and Ogle for their turnpike-road steam-carriage +consisted of a series of tubes placed +vertically over the furnace, through which the +heated air passed before reaching the chimney.</p> + +<p>About the same time George Stephenson was +trying the effect of introducing small tubes in the +boilers of his locomotives, with the object of increasing +their evaporative power. Thus, in 1829, +he sent to France two engines constructed at +the Newcastle works for the Lyons and St. +Etienne Railway, in the boilers of which tubes +were placed containing water. The heating surface<span class='pagenum'><a name="Page_172" id="Page_172">[Pg 172]</a></span> +was thus considerably increased; but the expedient +was not successful, for the tubes, becoming +furred with deposit, shortly burned out and +were removed. It was then that M. Seguin, the +engineer of the railway, pursuing the same idea, +is said to have adopted his plan of employing +horizontal tubes through which the heated air +passed in streamlets, and for which he took out a +French patent.</p> + +<p>In the meantime Mr. Henry Booth, secretary +to the Liverpool and Manchester Railway, whose +attention had been directed to the subject on the +prize being offered for the best locomotive to +work that line, proposed the same method, which, +unknown to him, Matthew Boulton had employed +but not patented, in 1780, and James +Neville had patented, but not employed, in 1826; +and it was carried into effect by Robert Stephenson +in the construction of the “Rocket,” which +won the prize at Rainhill in October, 1829. +The following is Mr. Booth's account in a letter +to the author:</p> + +<p>“I was in almost daily communication with +Mr. Stephenson at the time, and I was not aware +that he had any intention of competing for the +prize till I communicated to him my scheme of a +multitubular boiler. This new plan of boiler +comprised the introduction of numerous small +tubes, two or three inches in diameter, and less +than one-eighth of an inch thick, through which +to carry the fire instead of a single tube or flue +eighteen inches in diameter, and about half an<span class='pagenum'><a name="Page_173" id="Page_173">[Pg 173]</a></span> +inch thick, by which plan we not only obtain a +very much larger heating surface, but the heating +surface is much more effective, as there intervenes +between the fire and the water only a +thin sheet of copper or brass, not an eighth of an +inch thick, instead of a plate of iron of four times +the substance, as well as an inferior conductor +of heat.</p> + +<p>“When the conditions of trial were published, +I communicated my multitubular plan to Mr. +Stephenson, and proposed to him that we should +jointly construct an engine and compete for the +prize. Mr. Stephenson approved the plan, and +agreed to my proposal. He settled the mode in +which the fire-box and tubes were to be mutually +arranged and connected, and the engine was constructed +at the works of Messrs. Robert Stephenson +& Co., Newcastle-on-Tyne.</p> + +<p>“I am ignorant of M. Seguin's proceedings in +France, but I claim to be the inventor in England, +and feel warranted in stating, without +reservation, that until I named my plan to Mr. +Stephenson, with a view to compete for the prize +at Rainhill, it had not been tried, and was not +known in this country.”</p> + +<p>From the well-known high character of Mr. +Booth, we believe his statement to be made in +perfect good faith, and that he was as much in +ignorance of the plan patented by Neville as he +was of that of Seguin. As we have seen, from +the many plans of tubular boilers invented during +the preceding thirty years, the idea was not<span class='pagenum'><a name="Page_174" id="Page_174">[Pg 174]</a></span> +by any means new; and we believe Mr. Booth to +be entitled to the merit of inventing the method +by which the multitubular principle was so +effectually applied in the construction of the +famous “Rocket” engine.</p> + +<p>The principal circumstances connected with +the construction of the “Rocket,” as described +by Robert Stephenson to the author, may be +briefly stated. The tubular principle was adopted +in a more complete manner than had yet been +attempted. Twenty-five copper tubes, each three +inches in diameter, extended from one end of +the boiler to the other, the heated air passing +through them on its way to the chimney; and +the tubes being surrounded by the water of the +boiler, it will be obvious that a large extension +of the heating surface was thus effectually secured. +The principal difficulty was in fitting +the copper tubes in the boiler ends so as to prevent +leakage. They were manufactured by a +Newcastle coppersmith, and soldered to brass +screws which were screwed into the boiler ends, +standing out in great knobs. When the tubes +were thus fitted, and the boiler was filled with +water, hydraulic pressure was applied; but the +water squirted out at every joint, and the factory +floor was soon flooded. Robert went home in +despair; and in the first moment of grief he wrote +to his father that the whole thing was a failure. +By return of post came a letter from his father, +telling him that despair was not to be thought of—that +he must “try again;” and he suggested<span class='pagenum'><a name="Page_175" id="Page_175">[Pg 175]</a></span> +a mode of overcoming the difficulty, which his +son had already anticipated and proceeded to +adopt. It was, to bore clean holes in the boiler +ends, fit in the smooth copper tubes as tightly +as possible, solder up, and then raise the steam. +This plan succeeded perfectly, the expansion of +the copper tubes completely filling up all interstices, +and producing a perfectly water-tight +boiler, capable of withstanding extreme external +pressure.</p> + +<p>The mode of employing the steam-blast for +the purpose of increasing the draught in the +chimney was also the subject of numerous experiments. +When the engine was first tried, it +was thought that the blast in the chimney was +not sufficiently strong for the purpose of keeping +up the intensity of fire in the furnace, so as to +produce high-pressure steam with the required +velocity. The expedient was therefore adopted +of hammering the copper tubes at the point at +which they entered the chimney, whereby the +blast was considerably sharpened; and on a farther +trial it was found that the draught was increased +to such an extent as to enable abundance +of steam to be raised. The rationale of the +blast may be simply explained by referring to the +effect of contracting the pipe of a water-hose, +by which the force of the jet of water is proportionately +increased. Widen the nozzle of +the pipe, and the jet is in like manner diminished. +So it is with the steam-blast in the chimney of +the locomotive.<span class='pagenum'><a name="Page_176" id="Page_176">[Pg 176]</a></span></p> + +<p>Doubts were, however, expressed whether the +greater draught obtained by the contraction of +the blast-pipe was not counterbalanced in some +degree by the negative pressure upon the piston. +Hence a series of experiments was made with +pipes of different diameters, and their efficiency +was tested by the amount of vacuum that was +produced in the smoke-box. The degree of +rarefaction was determined by a glass tube fixed +to the bottom of the smoke-box and descending +into a bucket of water, the tube being open at +both ends. As the rarefaction took place, the +water would, of course, rise in the tube, and the +height to which it rose above the surface of the +water in the bucket was made the measure of the +amount of rarefaction. These experiments +proved that a considerable increase of draught +was obtained by the contraction of the orifice; +accordingly, the two blast-pipes opening from +the cylinders into either side of the “Rocket” +chimney, and turned up within it, were contracted +slightly below the area of the steam-ports, +and before the engine left the factory, the +water rose in the glass tube three inches above +the water in the bucket.</p> + +<p>The other arrangements of the “Rocket” were +briefly these: the boiler was cylindrical, with flat +ends, six feet in length, and three feet four inches +in diameter. The upper half of the boiler was +used as a reservoir for the steam, the lower half +being filled with water. Through the lower part +the copper tubes extended, being open to the<span class='pagenum'><a name="Page_177" id="Page_177">[Pg 177]</a></span> +fire-box at one end, and to the chimney at the +other. The fire-box, or furnace, two feet wide +and three feet high, was attached immediately +behind the boiler, and was also surrounded with +water. The cylinders of the engine were placed +on each side of the boiler, in an oblique position, +one end being nearly level with the top of the +boiler at its after end, and the other pointing +toward the centre of the foremost or driving pair +of wheels, with which the connection was directly +made from the piston-rod to a pin on the outside +of the wheel. The engine, together with its load +of water, weighed only four tons and a quarter; +and it was supported on four wheels, not coupled. +The tender was four-wheeled, and similar in +shape to a waggon—the foremost part holding the +fuel, and the hind part a water cask.</p> + +<p>When the “Rocket” was finished it was placed +upon the Killingworth Railway for the purpose +of experiment. The new boiler arrangement was +found perfectly successful. The steam was +raised rapidly and continuously, and in a quantity +which then appeared marvellous. The same +evening Robert despatched a letter to his father +at Liverpool, informing him, to his great joy, +that the “Rocket” was “all right,” and would +be in complete working trim by the day of +trial. The engine was shortly after sent by +waggon to Carlisle, and thence shipped for +Liverpool.</p> + +<p>The time so much longed for by George Stephenson +had now arrived, when the merits of the<span class='pagenum'><a name="Page_178" id="Page_178">[Pg 178]</a></span> +passenger locomotive were about to be put to the +test. He had fought the battle for it until now +almost single-handed. Engrossed by his daily +labours and anxieties, and harassed by difficulties +and discouragements which would have crushed +the spirit of a less resolute man, he had held +firmly to his purpose through good and through +evil report. The hostility which he experienced +from some of the directors opposed to the adoption +of the locomotive was the circumstance that +caused him the greatest grief of all; for where he +had looked for encouragement, he found only +carping and opposition. But his pluck never +failed him; and now the “Rocket” was +upon the ground to prove, to use his own +words, “whether he was a man of his word or +not.”</p> + +<p>On the day appointed for the great competition +of locomotives at Rainhill the following engines +were entered for the prize:</p> + +<p>1. Messrs. Braithwaite and Ericsson's “Novelty.”</p> + +<p>2. Mr. Timothy Hackworth's “Sanspareil.”</p> + +<p>3. Messrs. R. Stephenson & Co.'s “Rocket.”</p> + +<p>4. Mr. Burstall's “Perseverance.”</p> + +<p>The ground on which the engines were to be +tried was a level piece of railroad, about two miles +in length. Each was required to make twenty +trips, or equal to a journey of seventy miles, in +the course of the day, and the average rate of +travelling was to be not under ten miles an hour. +It was determined that, to avoid confusion, each<span class='pagenum'><a name="Page_179" id="Page_179">[Pg 179]</a></span> +engine should be tried separately, and on different +days.</p> + +<p>The day fixed for the competition was the 1st +of October, but, to allow sufficient time to get +the locomotives into good working order, the +directors extended it to the 6th. It was quite +characteristic of the Stephensons that, although +their engine did not stand first on the list for +trial, it was the first that was ready, and it was +accordingly ordered out by the judges for an +experimental trip. Yet the “Rocket” was by no +means the “favourite” with either the judges or +the spectators. Nicholas Wood has since stated +that the majority of the judges were strongly predisposed +in favour of the “Novelty,” and that +“nine-tenths, if not ten-tenths, of the persons +present were against the “Rocket” because of its +appearance.” Nearly every person favoured +some other engine, so that there was nothing for +the “Rocket” but the practical test. The first +trip made by it was quite successful. It ran +about twelve miles, without interruption, in +about fifty-three minutes.</p> + +<p>The “Novelty” was next called out. It was a +light engine, very compact in appearance, carrying +the water and fuel upon the same wheels as +the engine. The weight of the whole was only +three tons and one hundred-weight. A peculiarity +of this engine was that the air was driven +or <i>forced</i> through the fire by means of bellows. +The day being now far advanced, and some dispute +having arisen as to the method of assigning<span class='pagenum'><a name="Page_180" id="Page_180">[Pg 180]</a></span> +the proper load for the “Novelty,” no particular +experiment was made further than that the +engine traversed the line by way of exhibition, +occasionally moving at the rate of twenty-four +miles an hour. The “Sanspareil,” constructed +by Mr. Timothy Hackworth, was next exhibited, +but no particular experiment was made with it +on this day. This engine differed but little in +its construction from the locomotive last supplied +by the Stephensons to the Stockton and +Darlington Railway, of which Mr. Hackworth +was the locomotive foreman.</p> + +<p>The contest was postponed until the following +day; but, before the judges arrived on the ground, +the bellows for creating the blast in the “Novelty” +gave way, and it was found incapable of +going through its performance. A defect was also +detected in the boiler of the “Sanspareil,” and +some further time was allowed to get it repaired. +The large number of spectators who had assembled +to witness the contest were greatly disappointed +at this postponement; but, to lessen it, +Stephenson again brought out the “Rocket,” +and, attaching it to a coach containing thirty +persons, he ran them along the line at a rate of +from twenty-four to thirty miles an hour, much +to their gratification and amazement. Before +separating, the judges ordered the engine to be in +readiness by eight o'clock on the following morning, +to go through its definite trial according to +the prescribed conditions.</p> + +<p>On the morning of the 8th of October the<span class='pagenum'><a name="Page_181" id="Page_181">[Pg 181]</a></span> +“Rocket” was again ready for the contest. The +engine was taken to the extremity of the stage, +the fire-box was filled with coke, the fire lighted, +and the steam raised until it lifted the safety-valve +loaded to a pressure of fifty pounds to the square +inch. This proceeding occupied fifty-seven +minutes. The engine then started on its journey, +dragging after it about thirteen tons' weight in +waggons, and made the first ten trips backward +and forward along two miles of road, running the +thirty-five miles, including stoppages, in an hour +and forty-eight minutes. The second ten trips +were in like manner performed in two hours and +three minutes. The maximum velocity attained +during the trial trip was twenty-nine miles an +hour, or about three times the speed that one of +the judges of the competition had declared to be +the limit of possibility. The average speed at +which the whole of the journeys was performed +was fifteen miles an hour, or five miles beyond the +rate specified in the conditions published by the +company. The entire performance excited the +greatest astonishment among the assembled +spectators; the directors felt confident that their +enterprise was now on the eve of success; and +George Stephenson rejoiced to think that, in +spite of all false prophets and fickle counsellors, +the locomotive system was now safe. When the +“Rocket,” having performed all the conditions +of the contest, arrived at the “grand stand” at +the close of its day's successful run, Mr. Cropper—one +of the directors favourable to the fixed<span class='pagenum'><a name="Page_182" id="Page_182">[Pg 182]</a></span> +engine system—lifted up his hands, and exclaimed, +“Now has George Stephenson at last +delivered himself....”</p> + +<p>The “Rocket” had eclipsed the performance +of all locomotive engines that had yet been constructed, +and outstripped even the sanguine expectations +of its constructors. It satisfactorily +answered the report of Messrs. Walker and Rastrick, +and established the efficiency of the locomotive +for working the Liverpool and Manchester +Railway, and, indeed, all future railways. +The “Rocket” showed that a new power had +been born into the world, full of activity and +strength, with boundless capability of work. +It was the simple but admirable contrivance of +the steam-blast, and its combination with the +multitubular boiler, that at once gave locomotion +a vigorous life, and secured the triumph of the +railway system.<a name="FNanchor_8_8" id="FNanchor_8_8"></a><a href="#Footnote_8_8" class="fnanchor">[8]</a><span class='pagenum'><a name="Page_183" id="Page_183">[Pg 183]</a></span></p> + +<div class="figcenter" style="width: 500px;"> +<img src="images/il201.png" width="500" height="425" alt="The “Rocket”" title="The “Rocket”" /> +<span class="caption">The “Rocket”</span> +</div> +<br /> + +<div class="footnotes"><h3>FOOTNOTES:</h3> + +<div class="footnote"><p><a name="Footnote_7_7" id="Footnote_7_7"></a><a href="#FNanchor_7_7"><span class="label">[7]</span></a> The conditions were these: +</p><p> +1. The engine must effectually consume its own smoke. +</p><p> +2. The engine, if of six tons' weight, must be able to draw +after it, day by day, twenty tons' weight (including the +tender and water-tank) at <i>ten miles</i> an hour, with a pressure +of steam on the boiler not exceeding fifty pounds to the +square inch. +</p><p> +3. The boiler must have two safety-valves, neither of +which must be fastened down, and one of them be completely +out of the control of the engine-man. +</p><p> +4. The engine and boiler must be supported on springs, +and rest on six wheels, the height of the whole not exceeding +fifteen feet to the top of the chimney. +</p><p> +5. The engine, with water, must not weigh more than +six tons; but an engine of less weight would be preferred +on its drawing a proportionate load behind it; if of only +four and a half tons, then it might be put on only four wheels. +The company will be at liberty to test the boiler, etc., by a +pressure of one hundred and fifty pounds to the square inch. +</p><p> +6. A mercurial gauge must be affixed to the machine, +showing the steam pressure above forty-five pounds per +square inch. +</p><p> +7. The engine must be delivered, complete and ready for +trial, at the Liverpool end of the railway, not later than the +1st of October, 1829. +</p><p> +8. The price of the engine must not exceed £550. +</p><p> +Many persons of influence declared the conditions published +by the directors of the railway chimerical in the extreme. +One gentleman of some eminence in Liverpool, +Mr. P. Ewart, who afterward filled the office of Government +Inspector of Post-office Steam Packets, declared that only +a parcel of charlatans would ever have issued such a set of +conditions; that it had been <i>proved</i> to be impossible to make +a locomotive engine go at ten miles an hour; but if it ever +was done, he would undertake to eat a stewed engine-wheel +for his breakfast.</p></div> + +<div class="footnote"><p><a name="Footnote_8_8" id="Footnote_8_8"></a><a href="#FNanchor_8_8"><span class="label">[8]</span></a> When heavier and more powerful engines were brought +upon the road, the old “Rocket,” becoming regarded as a +thing of no value, was sold in 1837. It has since been transferred +to the Museum of Patents at South Kensington, London, +where it is still to be seen.</p></div> +</div> + +<div class="trans-note"> +<h3>Transcriber's Notes:</h3> + +<p><a href="#Page_30">Page 30</a>—imployed changed to employed.</p> + +<p><a href="#Page_31">Page 31</a>—subsequenty changed to subsequently.</p> + +<p><a href="#Page_47">Page 47</a>—build changed to building.</p> + +<p><a href="#Page_147">Page 147</a>—suggestor changed to suggester.</p> + +<p><a href="#Page_166">Page 166</a>—supgestion changed to suggestion.</p> + +<p><a href="#Footnote_7_7">Footnote 7</a>—Changed question mark for a period.</p> + +<p>Inconsistencies in hyphenated words have been made consistent.</p> + +<p>Obvious printer errors, including punctuation, have been corrected +without note.</p> +</div> + + + + + + + + +<pre> + + + + + +End of Project Gutenberg's Little Masterpieces of Science:, by Various + +*** END OF THIS PROJECT GUTENBERG EBOOK LITTLE MASTERPIECES OF SCIENCE: *** + +***** This file should be named 29241-h.htm or 29241-h.zip ***** +This and all associated files of various formats will be found in: + http://www.gutenberg.org/2/9/2/4/29241/ + +Produced by Sigal Alon, Marcia Brooks, Fox in the Stars +and the Online Distributed Proofreading Team at +http://www.pgdp.net + + +Updated editions will replace the previous one--the old editions +will be renamed. + +Creating the works from public domain print editions means that no +one owns a United States copyright in these works, so the Foundation +(and you!) can copy and distribute it in the United States without +permission and without paying copyright royalties. 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index 0000000..1434b3f --- /dev/null +++ b/29241-h/images/il201.png diff --git a/29241.txt b/29241.txt new file mode 100644 index 0000000..061e3be --- /dev/null +++ b/29241.txt @@ -0,0 +1,4627 @@ +The Project Gutenberg EBook of Little Masterpieces of Science:, by Various + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Little Masterpieces of Science: + Invention and Discovery + +Author: Various + +Editor: George Iles + +Release Date: June 25, 2009 [EBook #29241] + +Language: English + +Character set encoding: ASCII + +*** START OF THIS PROJECT GUTENBERG EBOOK LITTLE MASTERPIECES OF SCIENCE: *** + + + + +Produced by Sigal Alon, Marcia Brooks, Fox in the Stars +and the Online Distributed Proofreading Team at +http://www.pgdp.net + + + + + + + + + +LITTLE MASTERPIECES OF SCIENCE + +[Illustration: George Stephenson.] + + + + +Little Masterpieces +of Science + +Edited by George Iles + + + + +INVENTION AND DISCOVERY + + +_By_ + + +Benjamin Franklin Alexander Graham Bell +Michael Faraday Count Rumford +Joseph Henry George Stephenson + + +[Illustration] + + +NEW YORK + +DOUBLEDAY, PAGE & COMPANY + +1902 + + +Copyright, 1902, by Doubleday, Page & Co. + +Copyright, 1877, by George B. Prescott + +Copyright, 1896, by S. S. McClure Co. + +Copyright, 1900, by Doubleday, McClure & Co. + + + + +PREFACE + + +To a good many of us the inventor is the true hero for he multiplies the +working value of life. He performs an old task with new economy, as when +he devises a mowing-machine to oust the scythe; or he creates a service +wholly new, as when he bids a landscape depict itself on a photographic +plate. He, and his twin brother, the discoverer, have eyes to read a +lesson that Nature has held for ages under the undiscerning gaze of +other men. Where an ordinary observer sees, or thinks he sees, +diversity, a Franklin detects identity, as in the famous experiment here +recounted which proves lightning to be one and the same with a charge of +the Leyden jar. Of a later day than Franklin, advantaged therefor by new +knowledge and better opportunities for experiment, stood Faraday, the +founder of modern electric art. His work gave the world the dynamo and +motor, the transmission of giant powers, almost without toll, for two +hundred miles at a bound. It is, however, in the carriage of but +trifling quantities of motion, just enough for signals, that electricity +thus far has done its most telling work. Among the men who have created +the electric telegraph Joseph Henry has a commanding place. A short +account of what he did, told in his own words, is here presented. Then +follows a narrative of the difficult task of laying the first Atlantic +cables, a task long scouted as impossible: it is a story which proves +how much science may be indebted to unfaltering courage, to faith in +ultimate triumph. + +To give speech the wings of electricity, to enable friends in Denver and +New York to converse with one another, is a marvel which only +familiarity places beyond the pale of miracle. Shortly after he +perfected the telephone Professor Bell described the steps which led to +its construction. That recital is here reprinted. + +A recent wonder of electric art is its penetration by a photographic ray +of substances until now called opaque. Professor Roentgen's account of +how he wrought this feat forms one of the most stirring chapters in the +history of science. Next follows an account of the telegraph as it +dispenses with metallic conductors altogether, and trusts itself to that +weightless ether which brings to the eye the luminous wave. To this +succeeds a chapter which considers what electricity stands for as one of +the supreme resources of human wit, a resource transcending even flame +itself, bringing articulate speech and writing to new planes of facility +and usefulness. It is shown that the rapidity with which during a single +century electricity has been subdued for human service, illustrates that +progress has leaps as well as deliberate steps, so that at last a gulf, +all but infinite, divides man from his next of kin. + +At this point we pause to recall our debt to the physical philosophy +which underlies the calculations of the modern engineer. In such an +experiment as that of Count Rumford we observe how the corner-stone was +laid of the knowledge that heat is motion, and that motion under +whatever guise, as light, electricity, or what not, is equally beyond +creation or annihilation, however elusively it may glide from phase to +phase and vanish from view. In the mastery of Flame for the superseding +of muscle, of breeze and waterfall, the chief credit rests with James +Watt, the inventor of the steam engine. Beside him stands George +Stephenson, who devised the locomotive which by abridging space has +lengthened life and added to its highest pleasures. Our volume closes by +narrating the competition which decided that Stephenson's "Rocket" was +much superior to its rivals, and thus opened a new chapter in the +history of mankind. + +GEORGE ILES. + + + + +CONTENTS + + + FRANKLIN, BENJAMIN + + LIGHTNING IDENTIFIED WITH ELECTRICITY + + Franklin explains the action of the Leyden phial or jar. + Suggests lightning-rods. Sends a kite into the clouds during + a thunderstorm; through the kite-string obtains a spark + of lightning which throws into divergence the loose fibres + of the string, just as an ordinary electrical discharge + would do. 3 + + + FARADAY, MICHAEL + + PREPARING THE WAY FOR THE ELECTRIC DYNAMO AND MOTOR + + Notices the inductive effect in one coil when the circuit in + a concentric coil is completed or broken. Notices similar + effects when a wire bearing a current approaches another + wire or recedes from it. Rotates a galvanometer needle by + an electric pulse. Induces currents in coils when the magnetism + is varied in their iron or steel cores. Observes the lines + of magnetic force as iron filings are magnetized. A magnetic + bar moved in and out of a coil of wire excites electricity + therein,--mechanical motion is converted into electricity. + Generates a current by spinning a copper plate in a horizontal + plane. 7 + + + HENRY, JOSEPH + + INVENTION OF THE ELECTRIC TELEGRAPH + + Improves the electro-magnet of Sturgeon by insulating its + wire with silk thread, and by disposing the wire in several + coils instead of one. Experiments with a large electro-magnet + excited by nine distinct coils. Uses a battery so powerful + that electro-magnets are produced one hundred times more + energetic than those of Sturgeon. Arranges a telegraphic + circuit more than a mile long and at that distance sounds + a bell by means of an electro-magnet. 23 + + + ILES, GEORGE + + THE FIRST ATLANTIC CABLES + + Forerunners at New York and Dover. Gutta-percha the indispensable + insulator. Wire is used to sheathe the cables. Cyrus W. + Field's project for an Atlantic cable. The first cable fails. + 1858 so does the second cable 1865. A triumph of courage, + 1866. The highway smoothed for successors. Lessons of the + cable. 37 + + + BELL, ALEXANDER GRAHAM + + THE INVENTION OF THE TELEPHONE + + Indebted to his father's study of the vocal organs as they + form sounds. Examines the Helmholtz method for the analysis + and synthesis of vocal sounds. Suggests the electrical actuation + of tuning-forks and the electrical transmission of their + tones. Distinguishes intermittent, pulsatory and undulatory + currents. Devises as his first articulating telephone a harp + of steel rods thrown into vibration by electro-magnetism. + Exhibits optically the vibrations of sound, using a preparation + of a human ear: is struck by the efficiency of a slight + aural membrane. Attaches a bit of clock spring to a piece + of goldbeater's skin, speaks to it, an audible message is + received at a distant and similar device. This contrivance + improved is shown at the Centennial Exhibition, Philadelphia, + 1876. At first the same kind of instrument transmitted and + delivered, a message; soon two distinct instruments were + invented for transmitting and for receiving. Extremely small + magnets suffice. A single blade of grass forms a telephonic + circuit. 57 + + + DAM, H. J. W. + + PHOTOGRAPHING THE UNSEEN + + Roentgen indebted to the researches of Faraday, Clerk-Maxwell, + Hertz, Lodge and Lenard. The human optic nerve is affected + by a very small range in the waves that exist in the ether. + Beyond the visible spectrum of common light are vibrations + which have long been known as heat or as photographically + active. Crookes in a vacuous bulb produced soft light from + high tension electricity. Lenard found that rays from a + Crookes' tube passed through substances opaque to common + light. Roentgen extended these experiments and used the rays + photographically, taking pictures of the bones of the hand + through living flesh, and so on. 87 + + + ILES, GEORGE + + THE WIRELESS TELEGRAPH + + What may follow upon electric induction. Telegraphy to a + moving train. The Preece induction method; its limits. + Marconi's system. His precursors, Hertz, Onesti, Branly + and Lodge. The coherer and the vertical wire form the essence + of the apparatus. Wireless telegraphy at sea. 109 + + + ILES, GEORGE + + ELECTRICITY, WHAT ITS MASTERY MEANS: WITH A REVIEW AND A PROSPECT + + Electricity does all that fire ever did, does it better, + and performs uncounted services impossible to flame. Its + mastery means as great a forward stride as the subjugation + of fire. A minor invention or discovery simply adds to human + resources: a supreme conquest as of flame or electricity, + is a multiplier and lifts art and science to a new plane. + Growth is slow, flowering is rapid: progress at times is + so quick of pace as virtually to become a leap. The mastery + of electricity based on that of fire. Electricity vastly + wider of range than heat: it is energy in its most available + and desirable phase. The telegraph and the telephone contrasted + with the signal fire. Electricity as the servant of mechanic + and engineer. Household uses of the current. Electricity + as an agent of research now examines Nature in fresh aspects. + The investigator and the commercial exploiter render aid to + one another. Social benefits of electricity, in telegraphy, in + quick travel. The current should serve every city house. 125 + + + RUMFORD, COUNT (BENJAMIN THOMPSON) + + HEAT AND MOTION IDENTIFIED + + Observes that in boring a cannon much heat is generated: + the longer the boring lasts, the more heat is produced. He + argues that since heat without limit may be thus produced + by motion, heat must be motion. 155 + + + STEPHENSON, GEORGE + + THE "ROCKET" LOCOMOTIVE AND ITS VICTORY + + Shall it be a system of stationary engines or locomotives? + The two best practical engineers of the day are in favour + of stationary engines. A test of locomotives is, however, + proffered, and George Stephenson and his son, Robert, discuss + how they may best build an engine to win the first prize. + They adopt a steam blast to stimulate the draft of the furnace, + and raise steam quickly in a boiler having twenty-five small + fire-tubes of copper. The "Rocket" with a maximum speed of + twenty-nine miles an hour distances its rivals. With its + load of water its weight was but four and a quarter tons. 163 + + + + +INVENTION AND DISCOVERY + + + + +FRANKLIN IDENTIFIES LIGHTNING WITH ELECTRICITY + + [From Franklin's Works, edited in ten volumes by John Bigelow, Vol. + I, pages 276-281, copyright by G. P. Putnam's Sons, New York.] + + +Dr. Stuber, the author of the first continuation of Franklin's life, +gives this account of the electrical experiments of Franklin:-- + +"His observations he communicated, in a series of letters, to his friend +Collinson, the first of which is dated March 28, 1747. In these he shows +the power of points in drawing and throwing off the electrical matter, +which had hitherto escaped the notice of electricians. He also made the +grand discovery of a _plus_ and _minus_, or of a _positive_ and +_negative_ state of electricity. We give him the honour of this without +hesitation; although the English have claimed it for their countryman, +Dr. Watson. Watson's paper is dated January 21, 1748; Franklin's July +11, 1747, several months prior. Shortly after Franklin, from his +principles of the _plus_ and _minus_ state, explained in a satisfactory +manner the phenomena of the Leyden phial, first observed by Mr. Cuneus, +or by Professor Muschenbroeck, of Leyden, which had much perplexed +philosophers. He showed clearly that when charged the bottle contained +no more electricity than before, but that as much was taken from one +side as thrown on the other; and that to discharge it nothing was +necessary but to produce a communication between the two sides by which +the equilibrium might be restored, and that then no signs of electricity +would remain. He afterwards demonstrated by experiments that the +electricity did not reside in the coating as had been supposed, but in +the pores of the glass itself. After the phial was charged he removed +the coating, and found that upon applying a new coating the shock might +still be received. In the year 1749, he first suggested his idea of +explaining the phenomena of thunder gusts and of _aurora borealis_ upon +electric principles. He points out many particulars in which lightning +and electricity agree; and he adduces many facts, and reasonings from +facts, in support of his positions. + +"In the same year he conceived the astonishingly bold and grand idea of +ascertaining the truth of his doctrine by actually drawing down the +lightning, by means of sharp pointed iron rods raised into the regions +of the clouds. Even in this uncertain state his passion to be useful to +mankind displayed itself in a powerful manner. Admitting the identity of +electricity and lightning, and knowing the power of points in repelling +bodies charged with electricity, and in conducting fires silently and +imperceptibly, he suggested the idea of securing houses, ships and the +like from being damaged by lightning, by erecting pointed rods that +should rise some feet above the most elevated part, and descend some +feet into the ground or water. The effect of these he concluded would be +either to prevent a stroke by repelling the cloud beyond the striking +distance or by drawing off the electrical fire which it contained; or, +if they could not effect this they would at least conduct the electrical +matter to the earth without any injury to the building. + +"It was not until the summer of 1752 that he was enabled to complete his +grand and unparalleled discovery by experiment. The plan which he had +originally proposed was, to erect, on some high tower or elevated place, +a sentry-box from which should rise a pointed iron rod, insulated by +being fixed in a cake of resin. Electrified clouds passing over this +would, he conceived, impart to it a portion of their electricity which +would be rendered evident to the senses by sparks being emitted when a +key, the knuckle, or other conductor, was presented to it. Philadelphia +at this time afforded no opportunity of trying an experiment of this +kind. While Franklin was waiting for the erection of a spire, it +occurred to him that he might have more ready access to the region of +clouds by means of a common kite. He prepared one by fastening two cross +sticks to a silk handkerchief, which would not suffer so much from the +rain as paper. To the upright stick was affixed an iron point. The +string was, as usual, of hemp, except the lower end, which was silk. +Where the hempen string terminated, a key was fastened. With this +apparatus, on the appearance of a thundergust approaching, he went out +into the commons, accompanied by his son, to whom alone he communicated +his intentions, well knowing the ridicule which, too generally for the +interest of science, awaits unsuccessful experiments in philosophy. He +placed himself under a shed, to avoid the rain; his kite was raised, a +thunder-cloud passed over it, no sign of electricity appeared. He almost +despaired of success, when suddenly he observed the loose fibres of his +string to move towards an erect position. He now presented his knuckle +to the key and received a strong spark. How exquisite must his +sensations have been at this moment! On his experiment depended the fate +of his theory. If he succeeded, his name would rank high among those who +had improved science; if he failed, he must inevitably be subjected to +the derision of mankind, or, what is worse, their pity, as a +well-meaning man, but a weak, silly projector. The anxiety with which he +looked for the result of his experiment may easily be conceived. Doubts +and despair had begun to prevail, when the fact was ascertained, in so +clear a manner, that even the most incredulous could no longer withhold +their assent. Repeated sparks were drawn from the key, a phial was +charged, a shock given, and all the experiments made which are usually +performed with electricity." + + + + +FARADAY'S DISCOVERIES LEADING UP TO THE ELECTRIC DYNAMO AND MOTOR + + [Michael Faraday was for many years Professor of Natural Philosophy + at the Royal Institution, London, where his researches did more to + subdue electricity to the service of man than those of any other + physicist who ever lived. "Faraday as a Discoverer," by Professor + John Tyndall (his successor) depicts a mind of the rarest ability + and a character of the utmost charm. This biography is published by + D. Appleton & Co., New York: the extracts which follow are from the + third chapter.] + + +In 1831 we have Faraday at the climax of his intellectual strength, +forty years of age, stored with knowledge and full of original power. +Through reading, lecturing, and experimenting, he had become thoroughly +familiar with electrical science: he saw where light was needed and +expansion possible. The phenomena of ordinary electric induction +belonged, as it were, to the alphabet of his knowledge: he knew that +under ordinary circumstances the presence of an electrified body was +sufficient to excite, by induction, an unelectrified body. He knew that +the wire which carried an electric current was an electrified body, and +still that all attempts had failed to make it excite in other wires a +state similar to its own. + +What was the reason of this failure? Faraday never could work from the +experiments of others, however clearly described. He knew well that from +every experiment issues a kind of radiation, luminous, in different +degrees to different minds, and he hardly trusted himself to reason upon +an experiment that he had not seen. In the autumn of 1831 he began to +repeat the experiments with electric currents, which, up to that time, +had produced no positive result. And here, for the sake of younger +inquirers, if not for the sake of us all, it is worth while to dwell for +a moment on a power which Faraday possessed in an extraordinary degree. +He united vast strength with perfect flexibility. His momentum was that +of a river, which combines weight and directness with the ability to +yield to the flexures of its bed. The intentness of his vision in any +direction did not apparently diminish his power of perception in other +directions; and when he attacked a subject, expecting results, he had +the faculty of keeping his mind alert, so that results different from +those which he expected should not escape him through pre-occupation. + +He began his experiments "on the induction of electric currents" by +composing a helix of two insulated wires, which were wound side by side +round the same wooden cylinder. One of these wires he connected with a +voltaic battery of ten cells, and the other with a sensitive +galvanometer. When connection with the battery was made, and while the +current flowed, no effect whatever was observed at the galvanometer. +But he never accepted an experimental result, until he had applied to +it the utmost power at his command. He raised his battery from ten cells +to one hundred and twenty cells, but without avail. The current flowed +calmly through the battery wire without producing, during its flow, any +sensible result upon the galvanometer. + +"During its flow," and this was the time when an effect was +expected--but here Faraday's power of lateral vision, separating, as it +were from the line of expectation, came into play--he noticed that a +feeble movement of the needle always occurred at the moment when he made +contact with the battery; that the needle would afterwards return to its +former position and remain quietly there unaffected by the _flowing_ +current. At the moment, however, when the circuit was interrupted the +needle again moved, and in a direction opposed to that observed on the +completion of the circuit. + +This result, and others of a similar kind, led him to the conclusion +"that the battery current through the one wire did in reality induce a +similar current through the other; but that it continued for an instant +only, and partook more of the nature of the electric wave from a common +Leyden jar than of the current from a voltaic battery." The momentary +currents thus generated were called _induced currents_, while the +current which generated them was called the _inducing_ current. It was +immediately proved that the current generated at making the circuit was +always opposed in direction to its generator, while that developed on +the rupture of the circuit coincided in direction with the inducing +current. It appeared as if the current on its first rush through the +primary wire sought a purchase in the secondary one, and, by a kind of +kick, impelled backward through the latter an electric wave, which +subsided as soon as the primary current was fully established. + +Faraday, for a time, believed that the secondary wire, though quiescent +when the primary current had been once established, was not in its +natural condition, its return to that condition being declared by the +current observed at breaking the circuit. He called this hypothetical +state of the wire the _electro-tonic state_: he afterwards abandoned +this hypothesis, but seemed to return to it in after life. The term +electro-tonic is also preserved by Professor Du Bois Reymond to express +a certain electric condition of the nerves, and Professor Clerk Maxwell +has ably defined and illustrated the hypothesis in the Tenth Volume of +the "Transactions of the Cambridge Philosophical Society." + +The mere approach of a wire forming a closed curve to a second wire +through which a voltaic current flowed was then shown by Faraday to be +sufficient to arouse in the neutral wire an induced current, opposed in +direction to the inducing current; the withdrawal of the wire also +generated a current having the same direction as the inducing current; +those currents existed only during the time of approach or withdrawal, +and when neither the primary nor the secondary wire was in motion, no +matter how close their proximity might be, no induced current was +generated. + +Faraday has been called a purely inductive philosopher. A great deal of +nonsense is, I fear, uttered in this land of England about induction and +deduction. Some profess to befriend the one, some the other, while the +real vocation of an investigator, like Faraday, consists in the +incessant marriage of both. He was at this time full of the theory of +Ampere, and it cannot be doubted that numbers of his experiments were +executed merely to test his deductions from that theory. Starting from +the discovery of Oersted, the celebrated French philosopher had shown +that all the phenomena of magnetism then known might be reduced to the +mutual attractions and repulsions of electric currents. Magnetism had +been produced from electricity, and Faraday, who all his life long +entertained a strong belief in such reciprocal actions, now attempted to +effect the evolution of electricity from magnetism. Round a welded iron +ring he placed two distinct coils of covered wire, causing the coils to +occupy opposite halves of the ring. Connecting the ends of one of the +coils with a galvanometer, he found that the moment the ring was +magnetized, by sending a current through _the other coil_, the +galvanometer needle whirled round four or five times in succession. The +action, as before, was that of a pulse, which vanished immediately. On +interrupting the current, a whirl of the needle in the opposite +direction occurred. It was only during the time of magnetization or +demagnetization that these effects were produced. The induced currents +declared a _change_ of condition only, and they vanished the moment the +act of magnetization or demagnetization was complete. + +The effects obtained with the welded ring were also obtained with +straight bars of iron. Whether the bars were magnetized by the electric +current, or were excited by the contact of permanent steel magnets, +induced currents were always generated during the rise, and during the +subsidence of the magnetism. The use of iron was then abandoned, and the +same effects were obtained by merely thrusting a permanent steel magnet +into a coil of wire. A rush of electricity through the coil accompanied +the insertion of the magnet; an equal rush in the opposite direction +accompanied its withdrawal. The precision with which Faraday describes +these results, and the completeness with which he defined the boundaries +of his facts, are wonderful. The magnet, for example, must not be passed +quite through the coil, but only half through, for if passed wholly +through, the needle is stopped as by a blow, and then he shows how this +blow results from a reversal of the electric wave in the helix. He next +operated with the powerful permanent magnet of the Royal Society, and +obtained with it, in an exalted degree, all the foregoing phenomena. + +And now he turned the light of these discoveries upon the darkest +physical phenomenon of that day. Arago had discovered in 1824, that a +disk of non-magnetic metal had the power of bringing a vibrating +magnetic needle suspended over it rapidly to rest; and that on causing +the disk to rotate the magnetic needle rotated along with it. When both +were quiescent, there was not the slightest measurable attraction or +repulsion exerted between the needle and the disk; still when in motion +the disk was competent to drag after it, not only a light needle, but a +heavy magnet. The question had been probed and investigated with +admirable skill by both Arago and Ampere, and Poisson had published a +theoretic memoir on the subject; but no cause could be assigned for so +extraordinary an action. It had also been examined in this country by +two celebrated men, Mr. Babbage and Sir John Herschel; but it still +remained a mystery. Faraday always recommended the suspension of +judgment in cases of doubt. "I have always admired," he says, "the +prudence and philosophical reserve shown by M. Arago in resisting the +temptations to give a theory of the effect he had discovered, so long as +he could not devise one which was perfect in its application, and in +refusing to assent to the imperfect theories of others." Now, however, +the time for theory had come. Faraday saw mentally the rotating disk, +under the operation of the magnet, flooded with his induced currents, +and from the known laws of interaction between currents and magnets he +hoped to deduce the motion observed by Arago. That hope he realized, +showing by actual experiment that when his disk rotated currents passed +through it, their position and direction being such as must, in +accordance with the established laws of electro-magnetic action, produce +the observed rotation. + +Introducing the edge of his disk between the poles of the large +horseshoe magnet of the Royal Society, and connecting the axis and the +edge of the disk, each by a wire with a galvanometer, he obtained, when +the disk was turned round, a constant flow of electricity. The direction +of the current was determined by the direction of the motion, the +current being reversed when the rotation was reversed. He now states the +law which rules the production of currents in both disks and wires, and +in so doing uses, for the first time, a phrase which has since become +famous. When iron filings are scattered over a magnet, the particles of +iron arrange themselves in certain determined lines called magnetic +curves. In 1831, Faraday for the first time called these curves "lines +of magnetic force;" and he showed that to produce induced currents +neither approach to nor withdrawal from a magnetic source, or centre, or +pole, was essential, but that it was only necessary to cut appropriately +the lines of magnetic force. Faraday's first paper on Magneto-electric +Induction, which I have here endeavoured to condense, was read before +the Royal Society on the 24th of November, 1831. + +On January 12, 1832, he communicated to the Royal Society a second paper +on "Terrestrial Magneto-electric Induction," which was chosen as the +Bakerian Lecture for the year. He placed a bar of iron in a coil of +wire, and lifting the bar into the direction of the dipping needle, he +excited by this action a current in the coil. On reversing the bar, a +current in the opposite direction rushed through the wire. The same +effect was produced, when, on holding the helix in the line of dip, a +bar of iron was thrust into it. Here, however, the earth acted on the +coil through the intermediation of the bar of iron. He abandoned the bar +and simply set a copper-plate spinning in a horizontal plane; he knew +that the earth's lines of magnetic force then crossed the plate at an +angle of about 70 deg.. When the plate spun round, the lines of force were +intersected and induced currents generated, which produced their proper +effect when carried from the plate to the galvanometer. "When the plate +was in the magnetic meridian, or in any other plane coinciding with the +magnetic dip, then its rotation produced no effect upon the +galvanometer." + +At the suggestion of a mind fruitful in suggestions of a profound and +philosophic character--I mean that of Sir John Herschel--Mr. Barlow, of +Woolwich, had experimented with a rotating iron shell. Mr. Christie had +also performed an elaborate series of experiments on a rotating iron +disk. Both of them had found that when in rotation the body exercised a +peculiar action upon the magnetic needle, deflecting it in a manner +which was not observed during quiescence; but neither of them was aware +at the time of the agent which produced this extraordinary deflection. +They ascribed it to some change in the magnetism of the iron shell and +disk. + +But Faraday at once saw that his induced currents must come into play +here, and he immediately obtained them from an iron disk. With a hollow +brass ball, moreover, he produced the effects obtained by Mr. Barlow. +Iron was in no way necessary: the only condition of success was that the +rotating body should be of a character to admit of the formation of +currents in its substance: it must, in other words, be a conductor of +electricity. The higher the conducting power the more copious were the +currents. He now passes from his little brass globe to the globe of the +earth. He plays like a magician with the earth's magnetism. He sees the +invisible lines along which its magnetic action is exerted and sweeping +his wand across these lines evokes this new power. Placing a simple loop +of wire round a magnetic needle he bends its upper portion to the west: +the north pole of the needle immediately swerves to the east: he bends +his loop to the east, and the north poles moves to the west. Suspending +a common bar magnet in a vertical position, he causes it to spin round +its own axis. Its pole being connected with one end of a galvanometer +wire, and its equator with the other end, electricity rushes round the +galvanometer from the rotating magnet. He remarks upon the "_singular +independence_" of the magnetism and the body of the magnet which carries +it. The steel behaves as if it were isolated from its own magnetism. + +And then his thoughts suddenly widen, and he asks himself whether the +rotating earth does not generate induced currents as it turns round its +axis from west to east. In his experiment with the twirling magnet the +galvanometer wire remained at rest; one portion of the circuit was in +motion _relatively_ to _another portion_. But in the case of the +twirling planet the galvanometer wire would necessarily be carried along +with the earth; there would be no relative motion. What must be the +consequence? Take the case of a telegraph wire with its two terminal +plates dipped into the earth, and suppose the wire to lie in the +magnetic meridian. The ground underneath the wire is influenced like the +wire itself by the earth's rotation; if a current from south to north be +generated in the wire, a similar current from south to north would be +generated in the earth under the wire; these currents would run against +the same terminal plates, and thus neutralize each other. + +This inference appears inevitable, but his profound vision perceived its +possible invalidity. He saw that it was at least possible that the +difference of conducting power between the earth and the wire might +give one an advantage over the other, and that thus a residual or +differential current might be obtained. He combined wires of different +materials, and caused them to act in opposition to each other, but found +the combination ineffectual. The more copious flow in the better +conductor was exactly counterbalanced by the resistance of the worst. +Still, though experiment was thus emphatic, he would clear his mind of +all discomfort by operating on the earth itself. He went to the round +lake near Kensington Palace, and stretched four hundred and eighty feet +of copper wire, north and south, over the lake, causing plates soldered +to the wire at its ends to dip into the water. The copper wire was +severed at the middle, and the severed ends connected with a +galvanometer. No effect whatever was observed. But though quiescent +water gave no effect, moving water might. He therefore worked at London +Bridge for three days during the ebb and flow of the tide, but without +any satisfactory result. Still he urges, "Theoretically it seems a +necessary consequence, that where water is flowing there electric +currents should be formed. If a line be imagined passing from Dover to +Calais through the sea, and returning through the land, beneath the +water, to Dover, it traces out a circuit of conducting matter one part +of which, when the water moves up or down the channel, is cutting the +magnetic curves of the earth, while the other is relatively at rest.... +There is every reason to believe that currents do run in the general +direction of the circuit described, either one way or the other, +according as the passage of the waters is up or down the channel." This +was written before the submarine cable was thought of, and he once +informed me that actual observation upon that cable had been found to be +in accordance with his theoretic deduction. + +Three years subsequent to the publication of these researches, that is +to say on January 29, 1835, Faraday read before the Royal Society a +paper "On the influence by induction of an electric current upon +itself." A shock and spark of a peculiar character had been observed by +a young man named William Jenkin, who must have been a youth of some +scientific promise, but who, as Faraday once informed me, was dissuaded +by his own father from having anything to do with science. The +investigation of the fact noticed by Mr. Jenkin led Faraday to the +discovery of the _extra current_, or the current _induced in the primary +wire itself_ at the moments of making and breaking contact, the +phenomena of which he described and illustrated in the beautiful and +exhaustive paper referred to. + +Seven and thirty years have passed since the discovery of +magneto-electricity; but, if we except the _extra current_, until quite +recently nothing of moment was added to the subject. Faraday entertained +the opinion that the discoverer of a great law or principle had a right +to the "spoils"--this was his term--arising from its illustration; and +guided by the principle he had discovered, his wonderful mind, aided by +his wonderful ten fingers, overran in a single autumn this vast domain, +and hardly left behind him the shred of a fact to be gathered by his +successors. + +And here the question may arise in some minds, What is the use of it +all? The answer is, that if man's intellectual nature thirsts for +knowledge then knowledge is useful because it satisfies this thirst. If +you demand practical ends, you must, I think, expand your definition of +the term practical, and make it include all that elevates and enlightens +the intellect, as well as all that ministers to the bodily health and +comfort of men. Still, if needed, an answer of another kind might be +given to the question "what is its use?" As far as electricity has been +applied for medical purposes, it has been almost exclusively Faraday's +electricity. You have noticed those lines of wire which cross the +streets of London. It is Faraday's currents that speed from place to +place through these wires. Approaching the point of Dungeness, the +mariner sees an unusually brilliant light, and from the noble lighthouse +of La Heve the same light flashes across the sea. These are Faraday's +sparks exalted by suitable machinery to sun-like splendour. At the +present moment the Board of Trade and the Brethren of the Trinity House, +as well as the Commissioners of Northern Lights, are contemplating the +introduction of the Magneto-electric Light at numerous points upon our +coasts; and future generations will be able to refer to those guiding +stars in answer to the question, what has been the practical use of the +labours of Faraday? But I would again emphatically say, that his work +needs no justification, and that if he had allowed his vision to be +disturbed by considerations regarding the practical use of his +discoveries, those discoveries would never have been made by him. "I +have rather," he writes in 1831, "been desirous of discovering new facts +and new relations dependent on magneto-electric induction, than of +exalting the force of those already obtained; being assured that the +latter would find their full development hereafter." + +In 1817, when lecturing before a private society in London on the +element chlorine, Faraday thus expresses himself with reference to this +question of utility. "Before leaving this subject, I will point out the +history of this substance as an answer to those who are in the habit of +saying to every new fact, 'What is its use?' Dr. Franklin says to such, +'What is the use of an infant?' The answer of the experimentalist is, +'Endeavour to make it useful.' When Scheele discovered this substance, +it appeared to have no use; it was in its infancy and useless state, but +having grown up to maturity, witness its powers, and see what endeavours +to make it useful have done." + + + + +PROFESSOR JOSEPH HENRY'S INVENTION OF THE ELECTRIC TELEGRAPH + + [In 1855 the Regents of the Smithsonian Institution, Washington, D. + C., at the instance of their secretary, Professor Joseph Henry, + took evidence with respect to his claims as inventor of the + electric telegraph. The essential paragraphs of Professor Henry's + statement are taken from the Proceedings of the Board of Regents of + the Smithsonian Institution, Washington, 1857.] + + +There are several forms of the electric telegraph; first, that in which +frictional electricity has been proposed to produce sparks and motion of +pith balls at a distance. + +Second, that in which galvanism has been employed to produce signals by +means of bubbles of gas from the decomposition of water. + +Third, that in which electro-magnetism is the motive power to produce +motion at a distance; and again, of the latter there are two kinds of +telegraphs, those in which the intelligence is indicated by the motion +of a magnetic needle, and those in which sounds and permanent signs are +made by the attraction of an electro-magnet. The latter is the class to +which Mr. Morse's invention belongs. The following is a brief exposition +of the several steps which led to this form of the telegraph. + +The first essential fact which rendered the electro-magnetic telegraph +possible was discovered by Oersted, in the winter of 1819-'20. It is +illustrated by figure 1, in which the magnetic needle is deflected by +the action of a current of galvanism transmitted through the wire A B. + +[Illustration: Fig. 1] + +The second fact of importance, discovered in 1820, by Arago and Davy, is +illustrated in Fig. 2. It consists in this, that while a current of +galvanism is passing through a copper wire A B, it is magnetic, it +attracts iron filings and not those of copper or brass, and is capable +of developing magnetism in soft iron. + +[Illustration: Fig. 2] + +The next important discovery, also made in 1820, by Ampere, was that two +wires through which galvanic currents are passing in the same direction +attract, and in the opposite direction, repel, each other. On this fact +Ampere founded his celebrated theory, that magnetism consists merely in +the attraction of electrical currents revolving at right angles to the +line joining the two poles of the magnet. The magnetization of a bar of +steel or iron, according to this theory consists in establishing within +the metal by induction a series of electrical currents, all revolving in +the same direction at right angles to the axis or length of the bar. + +[Illustration: Fig. 3] + +It was this theory which led Arago, as he states, to adopt the method of +magnetizing sewing needles and pieces of steel wire, shown in Fig. 3. +This method consists in transmitting a current of electricity through a +helix surrounding the needle or wire to be magnetised. For the purpose +of insulation the needle was enclosed in a glass tube, and the several +turns of the helix were at a distance from each other to insure the +passage of electricity through the whole length of the wire, or, in +other words, to prevent it from seeking a shorter passage by cutting +across from one spire to another. The helix employed by Arago obviously +approximates the arrangement required by the theory of Ampere, in order +to develop by induction the magnetism of the iron. By an attentive +perusal of the original account of the experiments of Arago, it will be +seen that, properly speaking, he made no electro-magnet, as has been +asserted by Morse and others; his experiments were confined to the +magnetism of iron filings, to sewing needles and pieces of steel wire of +the diameter of a millimetre, or of about the thickness of a small +knitting needle. + +[Illustration: Fig. 4] + +Mr. Sturgeon, in 1825, made an important step in advance of the +experiments of Arago, and produced what is properly known as the +electro-magnet. He bent a piece of iron _wire_ into the form of a +horseshoe, covered it with varnish to insulate it, and surrounded it +with a helix, of which the spires were at a distance. When a current of +galvanism was passed through the helix from a small battery of a single +cup the iron wire became magnetic, and continued so during the passage +of the current. When the current was interrupted the magnetism +disappeared, and thus was produced the first temporary soft iron +magnet. + +The electro-magnet of Sturgeon is shown in Fig. 4. By comparing Figs. 3 +and 4 it will be seen that the helix employed by Sturgeon was of the +same kind as that used by Arago; instead however, of a straight steel +wire inclosed in a tube of glass, the former employed a bent wire of +soft iron. The difference in the arrangement at first sight might appear +to be small, but the difference in the results produced was important, +since the temporary magnetism developed in the arrangement of Sturgeon +was sufficient to support a weight of several pounds, and an instrument +was thus produced of value in future research. + +[Illustration: Fig. 5] + +The next improvement was made by myself. After reading an account of the +galvanometer of Schweigger, the idea occurred to me that a much nearer +approximation to the requirements of the theory of Ampere could be +attained by insulating the conducting wire itself, instead of the rod to +be magnetized, and by covering the whole surface of the iron with a +series of coils in close contact. This was effected by insulating a long +wire with silk thread, and winding this around the rod of iron in close +coils from one end to the other. The same principle was extended by +employing a still longer insulated wire, and winding several strata of +this over the first, care being taken to insure the insulation between +each stratum by a covering of silk ribbon. By this arrangement the rod +was surrounded by a compound helix formed of a long wire of many coils, +instead of a single helix of a few coils, (Fig. 5). + +In the arrangement of Arago and Sturgeon the several turns of wire were +not precisely at right angles to the axis of the rod, as they should be, +to produce the effect required by the theory, but slightly oblique, and +therefore each tended to develop a separate magnetism not coincident +with the axis of the bar. But in winding the wire over itself, the +obliquity of the several turns compensated each other, and the resultant +action was at right angles to the bar. The arrangement then introduced +by myself was superior to those of Arago and Sturgeon, first in the +greater multiplicity of turns of wire, and second in the better +application of these turns to the development of magnetism. The power of +the instrument with the same amount of galvanic force, was by this +arrangement several times increased. + +The maximum effect, however, with this arrangement and a single battery +was not yet obtained. After a certain length of wire had been coiled +upon the iron, the power diminished with a further increase of the +number of turns. This was due to the increased resistance which the +longer wire offered to the conduction of electricity. Two methods of +improvement therefore suggested themselves. The first consisted, not in +increasing the length of the coil, but in using a number of separate +coils on the same piece of iron. By this arrangement the resistance to +the conduction of the electricity was diminished and a greater quantity +made to circulate around the iron from the same battery. The second +method of producing a similar result consisted in increasing the number +of elements of the battery, or, in other words, the projectile force of +the electricity, which enabled it to pass through an increased number of +turns of wire, and thus, by increasing the length of the wire, to +develop the maximum power of the iron. + +[Illustration: Fig. 6] + +To test these principles on a larger scale, the experimental magnet was +constructed, which is shown in Fig. 6. In this a number of compound +helices were placed on the same bar, their ends left projecting, and so +numbered that they could be all united into one long helix, or variously +combined in sets of lesser length. + +From a series of experiments with this and other magnets it was proved +that, in order to produce the greatest amount of magnetism from a +battery of a single cup, a number of helices is required; but when a +compound battery is used, then one long wire must be employed, making +many turns around the iron, the length of wire and consequently the +number of turns being commensurate with the projectile power of the +battery. + +In describing the results of my experiments, the terms _intensity_ and +_quantity_ magnets were introduced to avoid circumlocution, and were +intended to be used merely in a technical sense. By the _intensity_ +magnet I designated a piece of soft iron, so surrounded with wire that +its magnetic power could be called into operation by an _intensity_ +battery, and by a _quantity_ magnet, a piece of iron so surrounded by a +number of separate coils, that its magnetism could be fully developed by +a _quantity_ battery. + +I was the first to point out this connection of the two kinds of the +battery with the two forms of the magnet, in my paper in _Silliman's +Journal_, January, 1831, and clearly to state that when magnetism was to +be developed by means of a compound battery, one long coil was to be +employed, and when the maximum effect was to be produced by a single +battery, a number of single strands were to be used. + +These steps in the advance of electro-magnetism, though small, were such +as to interest and astonish the scientific world. With the same battery +used by Mr. Sturgeon, at least a hundred times more magnetism was +produced than could have been obtained by his experiment. The +developments were considered at the time of much importance in a +scientific point of view, and they subsequently furnished the means by +which magneto-electricity, the phenomena of dia-magnetism, and the +magnetic effects on polarized light were discovered. They gave rise to +the various forms of electro-magnetic machines which have since +exercised the ingenuity of inventors in every part of the world, and +were of immediate applicability in the introduction of the magnet to +telegraphic purposes. Neither the electro-magnet of Sturgeon nor any +electro-magnet ever made previous to my investigations was applicable to +transmitting power to a distance. + +The principles I have developed were properly appreciated by the +scientific mind of Dr. Gale, and applied by him to operate Mr. Morse's +machine at a distance. + +Previous to my investigations the means of developing magnetism in soft +iron were imperfectly understood. The electro-magnet made by Sturgeon, +and copied by Dana, of New York, was an imperfect quantity magnet, the +feeble power of which was developed by a single battery. It was entirely +inapplicable to a long circuit with an intensity battery, and no person +possessing the requisite scientific knowledge, would have attempted to +use it in that connection after reading my paper. + +In sending a message to a distance, two circuits are employed, the +first a long circuit through which the electricity is sent to the +distant station to bring into action the second, a short one, in which +is the local battery and magnet for working the machine. In order to +give projectile force sufficient to send the power to a distance, it is +necessary to use an intensity battery in the long circuit, and in +connection with this, at the distant station, a magnet surrounded with +many turns of one long wire must be employed to receive and multiply the +effect of the current enfeebled by its transmission through the long +conductor. In the local or short circuit either an intensity or a +quantity magnet may be employed. If the first be used, then with it a +compound battery will be required; and, therefore on account of the +increased resistance due to the greater quantity of acid, a less amount +of work will be performed by a given amount of material; and, +consequently, though this arrangement is practicable it is by no means +economical. In my original paper I state that the advantages of a +greater conducting power, from using several wires in the quantity +magnet, may, in a less degree, be obtained by substituting for them one +large wire; but in this case, on account of the greater obliquity of the +spires and other causes, the magnetic effect would be less. In +accordance with these principles, the receiving magnet, or that which is +introduced into the long circuit, consists of a horseshoe magnet +surrounded with many hundred turns of a single long wire, and is +operated with a battery of from twelve to twenty-four elements or more, +while in the local circuit it is customary to employ a battery of one or +two elements with a much thicker wire and fewer turns. + +It will, I think, be evident to the impartial reader that these were +improvements in the electro-magnet, which first rendered it adequate to +the transmission of mechanical power to a distance; and had I omitted +all allusion to the telegraph in my paper, the conscientious historian +of science would have awarded me some credit, however small might have +been the advance which I made. Arago and Sturgeon, in the accounts of +their experiments, make no mention of the telegraph, and yet their names +always have been and will be associated with the invention. I briefly, +however, called attention to the fact of the applicability of my +experiments to the construction of the telegraph; but not being familiar +with the history of the attempts made in regard to this invention, I +called it "Barlow's project," while I ought to have stated that Mr. +Barlow's investigation merely tended to disprove the possibility of a +telegraph. + +I did not refer exclusively to the needle telegraph when, in my paper, I +stated that the _magnetic_ action of a current from a trough is at least +not sensibly diminished by passing through a long wire. This is evident +from the fact that the immediate experiment from which this deduction +was made was by means of an electro-magnet and not by means of a needle +galvanometer. + +[Illustration: Fig. 7] + +At the conclusion of the series of experiments which I described in +_Silliman's Journal_, there were two applications of the electro-magnet +in my mind: one the production of a machine to be moved by +electro-magnetism, and the other the transmission of or calling into +action power at a distance. The first was carried into execution in the +construction of the machine described in _Silliman's Journal_, vol. xx, +1831, and for the purpose of experimenting in regard to the second, I +arranged around one of the upper rooms in the Albany Academy a wire of +more than a mile in length, through which I was enabled to make signals +by sounding a bell, (Fig. 7.) The mechanical arrangement for effecting +this object was simply a steel bar, permanently magnetized, of about ten +inches in length, supported on a pivot, and placed with its north end +between the two arms of a horseshoe magnet. When the latter was excited +by the current, the end of the bar thus placed was attracted by one arm +of the horseshoe, and repelled by the other, and was thus caused to move +in a horizontal plane and its further extremity to strike a bell +suitably adjusted. + +I also devised a method of breaking a circuit, and thereby causing a +large weight to fall. It was intended to illustrate the practicability +of calling into action a great power at a distance capable of producing +mechanical effects; but as a description of this was not printed, I do +not place it in the same category with the experiments of which I +published an account, or the facts which could be immediately deduced +from my papers in _Silliman's Journal_. + +From a careful investigation of the history of electro-magnetism in its +connection with the telegraph, the following facts may be established: + +1. Previous to my investigations the means of developing magnetism in +soft iron were imperfectly understood, and the electro-magnet which then +existed was inapplicable to the transmission of power to a distance. + +2. I was the first to prove by actual experiment that, in order to +develop magnetic power at a distance, a galvanic battery of intensity +must be employed to project the current through the long conductor, and +that a magnet surrounded by many turns of one long wire must be used to +receive this current. + +3. I was the first actually to magnetize a piece of iron at a distance, +and to call attention to the fact of the applicability of my experiments +to the telegraph. + +4. I was the first to actually sound a bell at a distance by means of +the electro-magnet. + +5. The principles I had developed were applied by Dr. Gale to render +Morse's machine effective at a distance. + + + + +THE FIRST ATLANTIC CABLES + +GEORGE ILES + + [From "Flame, Electricity and the Camera," copyright Doubleday, + Page & Co., New York.] + + +Electric telegraphy on land has put a vast distance between itself and +the mechanical signalling of Chappe, just as the scope and availability +of the French invention are in high contrast with the rude signal fires +of the primitive savage. As the first land telegraphs joined village to +village, and city to city, the crossing of water came in as a minor +incident; the wires were readily committed to the bridges which spanned +streams of moderate width. Where a river or inlet was unbridged, or a +channel was too wide for the roadway of the engineer, the question +arose, May we lay an electric wire under water? With an ordinary land +line, air serves as so good a non-conductor and insulator that as a rule +cheap iron may be employed for the wire instead of expensive copper. In +the quest for non-conductors suitable for immersion in rivers, channels, +and the sea, obstacles of a stubborn kind were confronted. To overcome +them demanded new materials, more refined instruments, and a complete +revision of electrical philosophy. + +As far back as 1795, Francisco Salva had recommended to the Academy of +Sciences, Barcelona, the covering of subaqueous wires by resin, which +is both impenetrable by water and a non-conductor of electricity. +Insulators, indeed, of one kind and another, were common enough, but +each of them was defective in some quality indispensable for success. +Neither glass nor porcelain is flexible, and therefore to lay a +continuous line of one or the other was out of the question. Resin and +pitch were even more faulty, because extremely brittle and friable. What +of such fibres as hemp or silk, if saturated with tar or some other good +non-conductor? For very short distances under still water they served +fairly well, but any exposure to a rocky beach with its chafing action, +any rub by a passing anchor, was fatal to them. What the copper wire +needed was a covering impervious to water, unchangeable in composition +by time, tough of texture, and non-conducting in the highest degree. +Fortunately all these properties are united in gutta-percha: they exist +in nothing else known to art. Gutta-percha is the hardened juice of a +large tree (_Isonandra gutta_) common in the Malay Archipelago; it is +tough and strong, easily moulded when moderately heated. In comparison +with copper it is but one 60,000,000,000,000,000,000th as conductive. As +without gutta-percha there could be no ocean telegraphy, it is worth +while recalling how it came within the purview of the electrical +engineer. + +In 1843 Jose d'Almeida, a Portuguese engineer, presented to the Royal +Asiatic Society, London, the first specimens of gutta-percha brought to +Europe. A few months later, Dr. W. Montgomerie, a surgeon, gave other +specimens to the Society of Arts, of London, which exhibited them; but +it was four years before the chief characteristic of the gum was +recognized. In 1847 Mr. S. T. Armstrong of New York, during a visit to +London, inspected a pound or two of gutta-percha, and found it to be +twice as good a non-conductor as glass. The next year, through his +instrumentality, a cable covered with this new insulator was laid +between New York and Jersey City; its success prompted Mr Armstrong to +suggest that a similarly protected cable be submerged between America +and Europe. Eighteen years of untiring effort, impeded by the errors +inevitable to the pioneer, stood between the proposal and its +fulfilment. In 1848 the Messrs. Siemens laid under water in the port of +Kiel a wire covered with seamless gutta-percha, such as, beginning with +1847, they had employed for subterranean conductors. This particular +wire was not used for telegraphy, but formed part of a submarine-mine +system. In 1849 Mr. C. V. Walker laid an experimental line in the +English Channel; he proved the possibility of signalling for two miles +through a wire covered with gutta-percha, and so prepared the way for a +venture which joined the shores of France and England. + +[Illustration: Fig. 58.--Calais-Dover cable, 1851] + +In 1850 a cable twenty-five miles in length was laid from Dover to +Calais, only to prove worthless from faulty insulation and the lack of +armour against dragging anchors and fretting rocks. In 1851 the +experiment was repeated with success. The conductor now was not a single +wire of copper, but four wires, wound spirally, so as to combine +strength with flexibility; these were covered with gutta-percha and +surrounded with tarred hemp. As a means of imparting additional +strength, ten iron wires were wound round the hemp--a feature which has +been copied in every subsequent cable (Fig. 58). The engineers were fast +learning the rigorous conditions of submarine telegraphy; in its +essentials the Dover-Calais line continues to be the type of deep-sea +cables to-day. The success of the wire laid across the British Channel +incited other ventures of the kind. Many of them, through careless +construction or unskilful laying, were utter failures. At last, in 1855, +a submarine line 171 miles in length gave excellent service, as it +united Varna with Constantinople; this was the greatest length of +satisfactory cable until the submergence of an Atlantic line. + +In 1854 Cyrus W. Field of New York opened a new chapter in electrical +enterprise as he resolved to lay a cable between Ireland and +Newfoundland, along the shortest line that joins Europe to America. He +chose Valentia and Heart's Content, a little more than 1,600 miles +apart, as his termini, and at once began to enlist the co-operation of +his friends. Although an unfaltering enthusiast when once his great idea +had possession of him, Mr. Field was a man of strong common sense. From +first to last he went upon well-ascertained facts; when he failed he did +so simply because other facts, which he could not possibly know, had to +be disclosed by costly experience. Messrs. Whitehouse and Bright, +electricians to his company, were instructed to begin a preliminary +series of experiments. They united a continuous stretch of wires laid +beneath land and water for a distance of 2,000 miles, and found that +through this extraordinary circuit they could transmit as many as four +signals per second. They inferred that an Atlantic cable would offer but +little more resistance, and would therefore be electrically workable and +commercially lucrative. + +In 1857 a cable was forthwith manufactured, divided in halves, and +stowed in the holds of the _Niagara_ of the United States navy, and the +_Agamemnon_ of the British fleet. The _Niagara_ sailed from Ireland; the +sister ship proceeded to Newfoundland, and was to meet her in mid-ocean. +When the _Niagara_ had run out 335 miles of her cable it snapped under +a sudden increase of strain at the paying-out machinery; all attempts at +recovery were unavailing, and the work for that year was abandoned. The +next year it was resumed, a liberal supply of new cable having been +manufactured to replace the lost section, and to meet any fresh +emergency that might arise. A new plan of voyages was adopted: the +vessels now sailed together to mid-sea, uniting there both portions of +the cable; then one ship steamed off to Ireland, the other to the +Newfoundland coast. Both reached their destinations on the same day, +August 5, 1858, and, feeble and irregular though it was, an electric +pulse for the first time now bore a message from hemisphere to +hemisphere. After 732 despatches had passed through the wire it became +silent forever. In one of these despatches from London, the War Office +countermanded the departure of two regiments about to leave Canada for +England, which saved an outlay of about $250,000. This widely quoted +fact demonstrated with telling effect the value of cable telegraphy. + +Now followed years of struggle which would have dismayed any less +resolute soul than Mr. Field. The Civil War had broken out, with its +perils to the Union, its alarms and anxieties for every American heart. +But while battleships and cruisers were patrolling the coast from Maine +to Florida, and regiments were marching through Washington on their way +to battle, there was no remission of effort on the part of the great +projector. + +Indeed, in the misunderstandings which grew out of the war, and that at +one time threatened international conflict, he plainly saw how a cable +would have been a peace-maker. A single word of explanation through its +wire, and angry feelings on both sides of the ocean would have been +allayed at the time of the _Trent_ affair. In this conviction he was +confirmed by the English press; the London _Times_ said: "We nearly went +to war with America because we had no telegraph across the Atlantic." In +1859 the British government had appointed a committee of eminent +engineers to inquire into the feasibility of an Atlantic telegraph, with +a view to ascertaining what was wanting for success, and with the +intention of adding to its original aid in case the enterprise were +revived. In July, 1863, this committee presented a report entirely +favourable in its terms, affirming "that a well-insulated cable, +properly protected, of suitable specific gravity, made with care, tested +under water throughout its progress with the best-known apparatus, and +paid into the ocean with the most improved machinery, possesses every +prospect of not only being successfully laid in the first instance, but +may reasonably be relied upon to continue for many years in an efficient +state for the transmission of signals." + +Taking his stand upon this endorsement, Mr. Field now addressed himself +to the task of raising the large sum needed to make and lay a new cable +which should be so much better than the old ones as to reward its owners +with triumph. He found his English friends willing to venture the +capital required, and without further delay the manufacture of a new +cable was taken in hand. In every detail the recommendations of the +Scientific Committee were carried out to the letter, so that the cable +of 1865 was incomparably superior to that of 1858. First, the central +copper wire, which was the nerve along which the lightning was to run, +was nearly three times larger than before. The old conductor was a +strand consisting of seven fine wires, six laid around one, and weighed +but 107 pounds to the mile. The new was composed of the same number of +wires, but weighed 300 pounds to the mile. It was made of the finest +copper obtainable. + +To secure insulation, this conductor was first embedded in Chatterton's +compound, a preparation impervious to water, and then covered with four +layers of gutta-percha, which were laid on alternately with four thin +layers of Chatterton's compound. The old cable had but three coatings of +gutta-percha, with nothing between. Its entire insulation weighed but +261 pounds to the mile, while that of the new weighed 400 pounds.[1] The +exterior wires, ten in number, were of Bessemer steel, each separately +wound in pitch-soaked hemp yarn, the shore ends specially protected by +thirty-six wires girdling the whole. Here was a combination of the +tenacity of steel with much of the flexibility of rope. The insulation +of the copper was so excellent as to exceed by a hundredfold that of the +core of 1858--which, faulty though it was, had, nevertheless, sufficed +for signals. So much inconvenience and risk had been encountered in +dividing the task of cable-laying between two ships that this time it +was decided to charter a single vessel, the _Great Eastern_, which, +fortunately, was large enough to accommodate the cable in an unbroken +length. Foilhommerum Bay, about six miles from Valentia, was selected as +the new Irish terminus by the company. Although the most anxious care +was exercised in every detail, yet, when 1,186 miles had been laid, the +cable parted in 11,000 feet of water, and although thrice it was +grappled and brought toward the surface, thrice it slipped off the +grappling hooks and escaped to the ocean floor. Mr. Field was obliged to +return to England and face as best he might the men whose capital lay at +the bottom of the sea--perchance as worthless as so much Atlantic ooze. +With heroic persistence he argued that all difficulties would yield to a +renewed attack. There must be redoubled precautions and vigilance never +for a moment relaxed. Everything that deep-sea telegraphy has since +accomplished was at that moment daylight clear to his prophetic view. +Never has there been a more signal example of the power of enthusiasm to +stir cold-blooded men of business; never has there been a more striking +illustration of how much science may depend for success upon the +intelligence and the courage of capital. Electricians might have gone on +perfecting exquisite apparatus for ocean telegraphy, or indicated the +weak points in the comparatively rude machinery which made and laid the +cable, yet their exertions would have been wasted if men of wealth had +not responded to Mr. Field's renewed appeal for help. Thrice these men +had invested largely, and thrice disaster had pursued their ventures; +nevertheless they had faith surviving all misfortunes for a fourth +attempt. + +In 1866 a new company was organized, for two objects: first, to recover +the cable lost the previous year and complete it to the American shore; +second, to lay another beside it in a parallel course. The _Great +Eastern_ was again put in commission, and remodelled in accordance with +the experience of her preceding voyage. This time the exterior wires of +the cable were of galvanized iron, the better to resist corrosion. The +paying-out machinery was reconstructed and greatly improved. On July 13, +1866, the huge steamer began running out her cable twenty-five miles +north of the line struck out during the expedition of 1865; she arrived +without mishap in Newfoundland on July 27, and electrical communication +was re-established between America and Europe. The steamer now returned +to the spot where she had lost the cable a few months before; after +eighteen days' search it was brought to the deck in good order. Union +was effected with the cable stowed in the tanks below, and the prow of +the vessel was once more turned to Newfoundland. On September 8th this +second cable was safely landed at Trinity Bay. Misfortunes now were at +an end; the courage of Mr. Field knew victory at last; the highest +honors of two continents were showered upon him. + + 'Tis not the grapes of Canaan that repay, + But the high faith that failed not by the way. + +[Illustration: Fig. 59.--Commercial cable, 1894] + +What at first was as much a daring adventure as a business enterprise +has now taken its place as a task no more out of the common than +building a steamship, or rearing a cantilever bridge. Given its price, +which will include too moderate a profit to betray any expectation of +failure, and a responsible firm will contract to lay a cable across the +Pacific itself. In the Atlantic lines the uniformly low temperature of +the ocean floor (about 4 deg. C.), and the great pressure of the +superincumbent sea, co-operate in effecting an enormous enhancement both +in the insulation and in the carrying capacity of the wire. As an +example of recent work in ocean telegraphy let us glance at the cable +laid in 1894, by the Commercial Cable Company of New York. It unites +Cape Canso, on the northeastern coast of Nova Scotia, to Waterville, on +the southwestern coast of Ireland. The central portion of this cable +much resembles that of its predecessor in 1866. Its exterior armour of +steel wires is much more elaborate. The first part of Fig. 59 shows the +details of manufacture: the central copper core is covered with +gutta-percha, then with jute, upon which the steel wires are spirally +wound, followed by a strong outer covering. For the greatest depths at +sea, type _A_ is employed for a total length of 1,420 miles; the +diameter of this part of the cable is seven-eighths of an inch. As the +water lessens in depth the sheathing increases in size until the +diameter of the cable becomes one and one-sixteenth inches for 152 +miles, as type _B_. The cable now undergoes a third enlargement, and +then its fourth and last proportions are presented as it touches the +shore, for a distance of one and three-quarter miles, where type _C_ has +a diameter of two and one-half inches. The weights of material used in +this cable are: copper wire, 495 tons; gutta-percha, 315 tons; jute +yarn, 575 tons; steel wire, 3,000 tons; compound and tar, 1,075 tons; +total, 5,460 tons. The telegraph-ship _Faraday_, specially designed for +cable-laying, accomplished the work without mishap. + +Electrical science owes much to the Atlantic cables, in particular to +the first of them. At the very beginning it banished the idea that +electricity as it passes through metallic conductors has anything like +its velocity through free space. It was soon found, as Professor +Mendenhall says, "that it is no more correct to assign a definite +velocity to electricity than to a river. As the rate of flow of a river +is determined by the character of its bed, its gradient, and other +circumstances, so the velocity of an electric current is found to depend +on the conditions under which the flow takes place."[2] Mile for mile +the original Atlantic cable had twenty times the retarding effect of a +good aerial line; the best recent cables reduce this figure by nearly +one-half. + +In an extreme form, this slowing down reminds us of the obstruction of +light as it enters the atmosphere of the earth, of the further +impediment which the rays encounter if they pass from the air into the +sea. In the main the causes which hinder a pulse committed to a cable +are two: induction, and the electrostatic capacity of the wire, that is, +the capacity of the wire to take up a charge of its own, just as if it +were the metal of a Leyden jar. + +Let us first consider induction. As a current takes its way through the +copper core it induces in its surroundings a second and opposing +current. For this the remedy is one too costly to be applied. Were a +cable manufactured in a double line, as in the best telephonic circuits, +induction, with its retarding and quenching effects, would be +neutralized. Here the steel wire armour which encircles the cable plays +an unwelcome part. Induction is always proportioned to the conductivity +of the mass in which it appears; as steel is an excellent conductor, the +armour of an ocean cable, close as it is to the copper core, has induced +in it a current much stronger, and therefore more retarding, than if the +steel wire were absent. + +A word now as to the second difficulty in working beneath the sea--that +due to the absorbing power of the line itself. An Atlantic cable, like +any other extended conductor, is virtually a long, cylindrical Leyden +jar, the copper wire forming the inner coat, and its surroundings the +outer coat. Before a signal can be received at the distant terminus the +wire must first be charged. The effect is somewhat like transmitting a +signal through water which fills a rubber tube; first of all the tube +is distended, and its compression, or secondary effect, really transmits +the impulse. A remedy for this is a condenser formed of alternate sheets +of tin-foil and mica, _C_, connected with the battery, _B_, so as to +balance the electric charge of the cable wire (Fig. 60). In the first +Atlantic line an impulse demanded one-seventh of a second for its +journey. This was reduced when Mr. Whitehouse made the capital discovery +that the speed of a signal is increased threefold when the wire is +alternately connected with the zinc and copper poles of the battery. Sir +William Thomson ascertained that these successive pulses are most +effective when of proportioned lengths. He accordingly devised an +automatic transmitter which draws a duly perforated slip of paper under +a metallic spring connected with the cable. To-day 250 to 300 letters +are sent per minute instead of fifteen, as at first. + +[Illustration: Fig. 60.--Condenser] + +In many ways a deep-sea cable exaggerates in an instructive manner the +phenomena of telegraphy over long aerial lines. The two ends of a cable +may be in regions of widely diverse electrical potential, or pressure, +just as the readings of the barometer at these two places may differ +much. If a copper wire were allowed to offer itself as a gateless +conductor it would equalize these variations of potential with serious +injury to itself. Accordingly the rule is adopted of working the cable +not directly, as if it were a land line, but indirectly through +condensers. As the throb sent through such apparatus is but momentary, +the cable is in no risk from the strong currents which would course +through it if it were permitted to be an open channel. + +[Illustration: Fig. 61.--Reflecting galvanometer L, lamp; N, moving spot +of light reflected from mirror] + +A serious error in working the first cables was in supposing that they +required strong currents as in land lines of considerable length. The +very reverse is the fact. Mr. Charles Bright, in _Submarine Telegraphs_, +says: + +"Mr. Latimer Clark had the conductor of the 1865 and 1866 lines joined +together at the Newfoundland end, thus forming an unbroken length of +3,700 miles in circuit. He then placed some sulphuric acid in a very +small silver thimble, with a fragment of zinc weighing a grain or two. +By this primitive agency he succeeded in conveying signals through twice +the breadth of the Atlantic Ocean in little more than a second of time +after making contact. The deflections were not of a dubious character, +but full and strong, from which it was manifest than an even smaller +battery would suffice to produce somewhat similar effects." + +[Illustration: Fig. 62.--Siphon recorder] + +At first in operating the Atlantic cable a mirror galvanometer was +employed as a receiver. The principle of this receiver has often been +illustrated by a mischievous boy as, with a slight and almost +imperceptible motion of his hand, he has used a bit of looking-glass to +dart a ray of reflected sunlight across a wide street or a large room. +On the same plan, the extremely minute motion of a galvanometer, as it +receives the successive pulsations of a message, is magnified by a +weightless lever of light so that the words are easily read by an +operator (Fig. 61). This beautiful invention comes from the hands of Sir +William Thomson [now Lord Kelvin], who, more than any other electrician, +has made ocean telegraphy an established success. + +[Illustration: Fig. 63.--Siphon record. "Arrived yesterday"] + +In another receiver, also of his design, the siphon recorder, he began +by taking advantage of the fact, observed long before by Bose, that a +charge of electricity stimulates the flow of a liquid. In its original +form the ink-well into which the siphon dipped was insulated and charged +to a high voltage by an influence-machine; the ink, powerfully repelled, +was spurted from the siphon point to a moving strip of paper beneath +(Fig. 62). It was afterward found better to use a delicate mechanical +shaker which throws out the ink in minute drops as the cable current +gently sways the siphon back and forth (Fig. 63). + +Minute as the current is which suffices for cable telegraphy, it is +essential that the metallic circuit be not only unbroken, but unimpaired +throughout. No part of his duty has more severely taxed the resources of +the electrician than to discover the breaks and leaks in his ocean +cables. One of his methods is to pour electricity as it were, into a +broken wire, much as if it were a narrow tube, and estimate the length +of the wire (and consequently the distance from shore to the defect or +break) by the quantity of current required to fill it. + + +FOOTNOTES: + +[1] Henry M. Field, "History of the Atlantic Telegraph." New York: +Scribner, 1866. + +[2] "A Century of Electricity." Boston, Houghton, Mifflin & Co., 1887. + + + + +BELL'S TELEPHONIC RESEARCHES + + [From "Bell's Electric Speaking Telephones," by George B. Prescott, + copyright by D Appleton & Co., New York, 1884] + + +In a lecture delivered before the Society of Telegraph Engineers, in +London, October 31, 1877, Prof. A. G. Bell gave a history of his +researches in telephony, together with the experiments that he was led +to undertake in his endeavours to produce a practical system of multiple +telegraphy, and to realize also the transmission of articulate speech. +After the usual introduction, Professor Bell said in part: + +It is to-night my pleasure, as well as duty, to give you some account of +the telephonic researches in which I have been so long engaged. Many +years ago my attention was directed to the mechanism of speech by my +father, Alexander Melville Bell, of Edinburgh, who has made a life-long +study of the subject. Many of those present may recollect the invention +by my father of a means of representing, in a wonderfully accurate +manner, the positions of the vocal organs in forming sounds. Together we +carried on quite a number of experiments, seeking to discover the +correct mechanism of English and foreign elements of speech, and I +remember especially an investigation in which we were engaged +concerning the musical relations of vowel sounds. When vocal sounds are +whispered, each vowel seems to possess a particular pitch of its own, +and by whispering certain vowels in succession a musical scale can be +distinctly perceived. Our aim was to determine the natural pitch of each +vowel; but unexpected difficulties made their appearance, for many of +the vowels seemed to possess a double pitch--one due, probably, to the +resonance of the air in the mouth, and the other to the resonance of the +air contained in the cavity behind the tongue, comprehending the pharynx +and larynx. + +I hit upon an expedient for determining the pitch, which, at that time, +I thought to be original with myself. It consisted in vibrating a tuning +fork in front of the mouth while the positions of the vocal organs for +the various vowels were silently taken. It was found that each vowel +position caused the reinforcement of some particular fork or forks. + +I wrote an account of these researches to Mr. Alex. J. Ellis, of London. +In reply, he informed me that the experiments related had already been +performed by Helmholtz, and in a much more perfect manner than I had +done. Indeed, he said that Helmholtz had not only analyzed the vowel +sounds into their constituent musical elements, but had actually +performed the synthesis of them. + +He had succeeded in producing, artificially, certain of the vowel sounds +by causing tuning forks of different pitch to vibrate simultaneously by +means of an electric current. Mr. Ellis was kind enough to grant me an +interview for the purpose of explaining the apparatus employed by +Helmholtz in producing these extraordinary effects, and I spent the +greater part of a delightful day with him in investigating the subject. +At that time, however, I was too slightly acquainted with the laws of +electricity fully to understand the explanations given; but the +interview had the effect of arousing my interest in the subjects of +sound and electricity, and I did not rest until I had obtained +possession of a copy of Helmholtz's great work "The Theory of Tone," and +had attempted, in a crude and imperfect manner, it is true, to reproduce +his results. While reflecting upon the possibilities of the production +of sound by electrical means, it struck me that the principle of +vibrating a tuning fork by the intermittent attraction of an +electro-magnet might be applied to the electrical production of music. + +I imagined to myself a series of tuning forks of different pitches, +arranged to vibrate automatically in the manner shown by Helmholtz--each +fork interrupting, at every vibration, a voltaic current--and the +thought occurred, Why should not the depression of a key like that of a +piano direct the interrupted current from any one of these forks, +through a telegraph wire, to a series of electro-magnets operating the +strings of a piano or other musical instrument, in which case a person +might play the tuning fork piano in one place and the music be audible +from the electro-magnetic piano in a distant city. + +The more I reflected upon this arrangement the more feasible did it seem +to me; indeed, I saw no reason why the depression of a number of keys at +the tuning fork end of the circuit should not be followed by the audible +production of a full chord from the piano in the distant city, each +tuning fork affecting at the receiving end that string of the piano with +which it was in unison. At this time the interest which I felt in +electricity led me to study the various systems of telegraphy in use in +this country and in America. I was much struck with the simplicity of +the Morse alphabet, and with the fact that it could be read by sound. +Instead of having the dots and dashes recorded on paper, the operators +were in the habit of observing the duration of the click of the +instruments, and in this way were enabled to distinguish by ear the +various signals. + +It struck me that in a similar manner the duration of a musical note +might be made to represent the dot or dash of the telegraph code, so +that a person might operate one of the keys of the tuning fork piano +referred to above, and the duration of the sound proceeding from the +corresponding string of the distant piano be observed by an operator +stationed there. It seemed to me that in this way a number of distinct +telegraph messages might be sent simultaneously from the tuning fork +piano to the other end of the circuit by operators, each manipulating a +different key of the instrument. These messages would be read by +operators stationed at the distant piano, each receiving operator +listening for signals for a certain definite pitch, and ignoring all +others. In this way could be accomplished the simultaneous transmission +of a number of telegraphic messages along a single wire, the number +being limited only by the delicacy of the listener's ear. The idea of +increasing the carrying power of a telegraph wire in this way took +complete possession of my mind, and it was this practical end that I had +in view when I commenced my researches in electric telephony. + +[Illustration: Fig. 1] + +In the progress of science it is universally found that complexity leads +to simplicity, and in narrating the history of scientific research it is +often advisable to begin at the end. + +In glancing back over my own researches, I find it necessary to +designate, by distinct names, a variety of electrical currents by means +of which sounds can be produced, and I shall direct your attention to +several distinct species of what may be termed telephonic currents of +electricity. In order that the peculiarities of these currents may be +clearly understood, I shall project upon the screen a graphical +illustration of the different varieties. + +The graphical method of representing electrical currents shown in Fig. 1 +is the best means I have been able to devise of studying, in an accurate +manner, the effects produced by various forms of telephonic apparatus, +and it has led me to the conception of that peculiar species of +telephonic current, here designated as _undulatory_, which has rendered +feasible the artificial production of articulate speech by electrical +means. + +A horizontal line (_g g'_) is taken as the zero of current, and impulses +of positive electricity are represented above the zero line, and +negative impulses below it, or _vice versa_. + +The vertical thickness of any electrical impulse (_b_ or _d_), measured +from the zero line, indicates the intensity of the electrical current at +the point observed; and the horizontal extension of the electric line +(_b_ or _d_) indicates the duration of the impulse. + +Nine varieties of telephonic currents may be distinguished, but it will +only be necessary to show you six of these. The three primary varieties +designated as intermittent, pulsatory and undulatory, are represented in +lines 1, 2 and 3. + +Sub-varieties of these can be distinguished as direct or reversed +currents, according as the electrical impulses are all of one kind or +are alternately positive and negative. Direct currents may still +further be distinguished as positive or negative, according as the +impulses are of one kind or of the other. + +An intermittent current is characterized by the alternate presence and +absence of electricity upon the circuit. + +A pulsatory current results from sudden or instantaneous changes in the +intensity of a continuous current; and + +An undulatory current is a current of electricity, the intensity of +which varies in a manner proportional to the velocity of the motion of a +particle of air during the production of a sound: thus the curve +representing graphically the undulatory current for a simple musical +note is the curve expressive of a simple pendulous vibration--that is, a +sinusoidal curve. + +And here I may remark, that, although the conception of the undulatory +current of electricity is entirely original with myself, methods of +producing sound by means of intermittent and pulsatory currents have +long been known. For instance, it was long since discovered that an +electro-magnet gives forth a decided sound when it is suddenly +magnetized or demagnetized. When the circuit upon which it is placed is +rapidly made and broken, a succession of explosive noises proceeds from +the magnet. These sounds produce upon the ear the effect of a musical +note when the current is interrupted a sufficient number of times per +second.... + +[Illustration: Fig. 2] + +For several years my attention was almost exclusively directed to the +production of an instrument for making and breaking a voltaic circuit +with extreme rapidity, to take the place of the transmitting tuning fork +used in Helmholtz's researches. Without going into details, I shall +merely say that the great defects of this plan of multiple telegraphy +were found to consist, first, in the fact that the receiving operators +were required to possess a good musical ear in order to discriminate the +signals; and secondly, that the signals could only pass in one direction +along the line (so that two wires would be necessary in order to +complete communication in both directions). The first objection was got +over by employing the device which I term a "vibratory circuit breaker," +whereby musical signals can be automatically recorded.... + +I have formerly stated that Helmholtz was enabled to produce vowel +sounds artificially by combining musical tones of different pitches and +intensities. His apparatus is shown in Fig. 2. Tuning forks of different +pitch are placed between the poles of electro-magnets (_a1_, _a2_, &c.), +and are kept in continuous vibration by the action of an intermittent +current from the fork _b_. Resonators, 1, 2, 3, etc., are arranged so as +to reinforce the sounds in a greater or less degree, according as the +exterior orifices are enlarged or contracted. + +[Illustration: Fig. 3] + +Thus it will be seen that upon Helmholtz's plan the tuning forks +themselves produce tones of uniform intensity, the loudness being varied +by an external reinforcement; but it struck me that the same results +would be obtained, and in a much more perfect manner, by causing the +tuning forks themselves to vibrate with different degrees of amplitude. +I therefore devised the apparatus shown in Fig. 3, which was my first +form of articulating telephone. In this figure a harp of steel rods is +employed, attached to the poles of a permanent magnet, N. S. When any +one of the rods is thrown into vibration an undulatory current is +produced in the coils of the electro-magnet E, and the electro-magnet E' +attracts the rods of the harp H' with a varying force, throwing into +vibration that rod which is in unison with that vibrating at the other +end of the circuit. Not only so, but the amplitude of vibration in the +one will determine the amplitude of vibration in the other, for the +intensity of the induced current is determined by the amplitude of the +inducing vibration, and the amplitude of the vibration at the receiving +end depends upon the intensity of the attractive impulses. When we sing +into a piano, certain of the strings of the instrument are set in +vibration sympathetically by the action of the voice with different +degrees of amplitude, and a sound, which is an approximation to the +vowel uttered, is produced from the piano. Theory shows that, had the +piano a very much larger number of strings to the octave, the vowel +sounds would be perfectly reproduced. My idea of the action of the +apparatus, shown in Fig. 3, was this: Utter a sound in the neighbourhood +of the harp H, and certain of the rods would be thrown into vibration +with different amplitudes. At the other end of the circuit the +corresponding rods of the harp H would vibrate with their proper +relations of force, and the _timbre_ [characteristic quality] of the +sound would be reproduced. The expense of constructing such an apparatus +as that shown in figure 3 deterred me from making the attempt, and I +sought to simplify the apparatus before venturing to have it made. + +[Illustration: Fig. 4] + +[Illustration: Fig. 5] + +[Illustration: Fig. 6] + +I have before alluded to the invention by my father of a system of +physiological symbols for representing the action of the vocal organs, +and I had been invited by the Boston Board of Education to conduct a +series of experiments with the system in the Boston school for the deaf +and dumb. It is well known that deaf mutes are dumb merely because they +are deaf, and that there is no defect in their vocal organs to +incapacitate them from utterance. Hence it was thought that my father's +system of pictorial symbols, popularly known as visible speech, might +prove a means whereby we could teach the deaf and dumb to use their +vocal organs and to speak. The great success of these experiments urged +upon me the advisability of devising method of exhibiting the vibrations +of sound optically, for use in teaching the deaf and dumb. For some time +I carried on experiments with the manometric capsule of Koeenig and with +the phonautograph of Leon Scott. The scientific apparatus in the +Institute of Technology in Boston was freely placed at my disposal for +these experiments, and it happened that at that time a student of the +Institute of Technology, Mr. Maurey, had invented an improvement upon +the phonautograph. He had succeeded in vibrating by the voice a stylus +of wood about a foot in length, which was attached to the membrane of +the phonautograph, and in this way he had been enabled to obtain +enlarged tracings upon a plane surface of smoked glass. With this +apparatus I succeeded in producing very beautiful tracings of the +vibrations of the air for vowel sounds. Some of these tracings are shown +in Fig. 4. I was much struck with this improved form of apparatus, and +it occurred to me that there was a remarkable likeness between the +manner in which this piece of wood was vibrated by the membrane of the +phonautograph and the manner in which the _ossiculo_ [small bones] of +the human ear were moved by the tympanic membrane. I determined +therefore, to construct a phonautograph modelled still more closely +upon the mechanism of the human ear, and for this purpose I sought the +assistance of a distinguished aurist in Boston, Dr. Clarence J. Blake. +He suggested the use of the human ear itself as a phonautograph, instead +of making an artificial imitation of it. The idea was novel and struck +me accordingly, and I requested my friend to prepare a specimen for me, +which he did. The apparatus, as finally constructed, is shown in Fig. 5. +The _stapes_ [inmost of the three auditory ossicles] was removed and a +pointed piece of hay about an inch in length was attached to the end of +the incus [the middle of the three auditory ossicles]. Upon moistening +the membrana tympani [membrane of the ear drum] and the ossiculae with a +mixture of glycerine and water the necessary mobility of the parts was +obtained, and upon singing into the external artificial ear the piece of +hay was thrown into vibration, and tracings were obtained upon a plane +surface of smoked glass passed rapidly underneath. While engaged in +these experiments I was struck with the remarkable disproportion in +weight between the membrane and the bones that were vibrated by it. It +occurred to me that if a membrane as thin as tissue paper could control +the vibration of bones that were, compared to it, of immense size and +weight, why should not a larger and thicker membrane be able to vibrate +a piece of iron in front of an electro-magnet, in which case the +complication of steel rods shown in my first form of telephone, Fig. 3, +could be done away with, and a simple piece of iron attached to a +membrane be placed at either end of the telegraphic circuit. + +Figure 6 shows the form of apparatus that I was then employing for +producing undulatory currents of electricity for the purpose of multiple +telegraphy. A steel reed, A, was clamped firmly by one extremity to the +uncovered leg _h_ of an electro-magnet E, and the free end of the reed +projected above the covered leg. When the reed A was vibrated in any +mechanical way the battery current was thrown into waves, and electrical +undulations traversed the circuit B E W E', throwing into vibration the +corresponding reed A' at the other end of the circuit. I immediately +proceeded to put my new idea to the test of practical experiment, and +for this purpose I attached the reed A (Fig. 7) loosely by one extremity +to the uncovered pole _h_ of the magnet, and fastened the other +extremity to the centre of a stretched membrane of goldbeaters' skin +_n_. I presumed that upon speaking in the neighbourhood of the membrane +_n_ it would be thrown into vibration and cause the steel reed A to move +in a similar manner, occasioning undulations in the electrical current +that would correspond to the changes in the density of the air during +the production of the sound; and I further thought that the change of +the density of the current at the receiving end would cause the magnet +there to attract the reed A' in such a manner that it should copy the +motion of the reed A, in which case its movements would occasion a sound +from the membrane _n'_ similar in _timbre_ to that which had occasioned +the original vibration. + +[Illustration: Fig. 7] + +[Illustration: Fig. 8] + +The results, however, were unsatisfactory and discouraging. My friend, +Mr. Thomas A. Watson, who assisted me in this first experiment, declared +that he heard a faint sound proceed from the telephone at his end of the +circuit, but I was unable to verify his assertion. After many +experiments, attended by the same only partially successful results, I +determined to reduce the size and weight of the spring as much as +possible. For this purpose I glued a piece of clock spring about the +size and shape of my thumb nail, firmly to the centre of the diaphragm, +and had a similar instrument at the other end (Fig. 8); we were then +enabled to obtain distinctly audible effects. I remember an experiment +made with this telephone, which at the time gave me great satisfaction +and delight. One of the telephones was placed in my lecture room in the +Boston University, and the other in the basement of the adjoining +building. One of my students repaired to the distant telephone to +observe the effects of articulate speech, while I uttered the sentence, +"Do you understand what I say?" into the telephone placed in the lecture +hall. To my delight an answer was returned through the instrument +itself, articulate sounds proceeded from the steel spring attached to +the membrane, and I heard the sentence, "Yes, I understand you +perfectly." It is a mistake, however, to suppose that the articulation +was by any means perfect, and expectancy no doubt had a great deal to do +with my recognition of the sentence; still, the articulation was there, +and I recognized the fact that the indistinctness was entirely due to +the imperfection of the instrument. I will not trouble you by detailing +the various stages through which the apparatus passed, but shall merely +say that after a time I produced the form of instrument shown in Fig. 9, +which served very well as a receiving telephone. In this condition my +invention was, in 1876, exhibited at the Centennial Exhibition in +Philadelphia. The telephone shown in Fig. 8 was used as a transmitting +instrument, and that in Fig. 9 as a receiver, so that vocal +communication was only established in one direction.... + +[Illustration: Fig. 9] + +The articulation produced from the instrument shown in Fig. 9 was +remarkably distinct, but its great defect consisted in the fact that it +could not be used as a transmitting instrument, and thus two telephones +were required at each station, one for transmitting and one for +receiving spoken messages. + +[Illustration: Fig. 10] + +It was determined to vary the construction of the telephone shown in +Fig. 8, and I sought, by changing the size and tension of the membrane, +the diameter and thickness of the steel spring, the size and power of +the magnet, and the coils of insulated wire around their poles, to +discover empirically the exact effect of each element of the +combination, and thus to deduce a more perfect form of apparatus. It was +found that a marked increase in the loudness of the sounds resulted from +shortening the length of the coils of wire, and by enlarging the iron +diaphragm which was glued to the membrane. In the latter case, also, the +distinctness of the articulation was improved. Finally, the membrane of +goldbeaters' skin was discarded entirely, and a simple iron plate was +used instead, and at once intelligible articulation was obtained. The +new form of instrument is that shown in Fig. 10, and, as had been long +anticipated, it was proved that the only use of the battery was to +magnetize the iron core, for the effects were equally audible when the +battery was omitted and a rod of magnetized steel substituted for the +iron core of the magnet. + +[Illustration: Fig. 11] + +It was my original intention, as shown in Fig. 3, and it was always +claimed by me, that the final form of telephone would be operated by +permanent magnets in place of batteries, and numerous experiments had +been carried on by Mr. Watson and myself privately for the purpose of +producing this effect. + +At the time the instruments were first exhibited in public the results +obtained with permanent magnets were not nearly so striking as when a +voltaic battery was employed, wherefore we thought it best to exhibit +only the latter form of instrument. + +The interest excited by the first published accounts of the operation of +the telephone led many persons to investigate the subject, and I doubt +not that numbers of experimenters have independently discovered that +permanent magnets might be employed instead of voltaic batteries. +Indeed, one gentleman, Professor Dolbear, of Tufts College, not only +claims to have discovered the magneto-electric telephone, but, I +understand, charges me with having obtained the idea from him through +the medium of a mutual friend. + +A still more powerful form of apparatus was constructed by using a +powerful compound horseshoe magnet in place of the straight rod which +had been previously used (see Fig. 11). Indeed, the sounds produced by +means of this instrument were of sufficient loudness to be faintly +audible to a large audience, and in this condition the instrument was +exhibited in the Essex Institute, in Salem, Massachusetts, on the 12th +of February, 1877, on which occasion a short speech shouted into a +similar telephone in Boston sixteen miles away, was heard by the +audience in Salem. The tones of the speaker's voice were distinctly +audible to an audience of six hundred people, but the articulation was +only distinct at a distance of about six feet. On the same occasion, +also, a report of the lecture was transmitted by word of mouth from +Salem to Boston, and published in the papers the next morning. + +From the form of telephone shown in Fig. 10 to the present form of the +instrument (Fig. 12) is but a step. It is, in fact, the arrangement of +Fig. 10 in a portable form, the magnet F. H. being placed inside the +handle and a more convenient form of mouthpiece provided.... + +It was always my belief that a certain ratio would be found between the +several parts of a telephone, and that the size of the instrument was +immaterial; but Professor Peirce was the first to demonstrate the +extreme smallness of the magnets which might be employed. And here, in +order to show the parallel lines in which we were working, I may mention +the fact that two or three days after I had constructed a telephone of +the portable form (Fig. 12), containing the magnet inside the handle, +Dr. Channing was kind enough to send me a pair of telephones of a +similar pattern, which had been invented by experimenters at Providence. +The convenient form of the mouthpiece shown in Fig. 12, now adopted by +me, was invented solely by my friend, Professor Peirce. I must also +express my obligations to my friend and associate, Mr. Thomas A. Watson, +of Salem, Massachusetts, who has for two years past given me his +personal assistance in carrying on my researches. + +In pursuing my investigations I have ever had one end in view--the +practical improvement of electric telegraphy--but I have come across +many facts which, while having no direct bearing upon the subject of +telegraphy, may yet possess an interest for you. + +For instance, I have found that a musical tone proceeds from a piece of +plumbago or retort carbon when an intermittent current of electricity is +passed through it, and I have observed the most curious audible effects +produced by the passage of reversed intermittent currents through the +human body. A breaker was placed in circuit with the primary wires of an +induction coil, and the fine wires were connected with two strips of +brass. One of these strips was held closely against the ear, and a loud +sound proceeded from it whenever the other slip was touched with the +other hand. The strips of brass were next held one in each hand. The +induced currents occasioned a muscular tremor in the fingers. Upon +placing my forefinger to my ear a loud crackling noise was audible, +seemingly proceeding from the finger itself. A friend who was present +placed my finger to his ear, but heard nothing. I requested him to hold +the strips himself. He was then distinctly conscious of a noise (which I +was unable to perceive) proceeding from his finger. In this case a +portion of the induced current passed through the head of the observer +when he placed his ear against his own finger, and it is possible that +the sound was occasioned by a vibration of the surfaces of the ear and +finger in contact. + +When two persons receive a shock from a Ruhmkorff's coil by clasping +hands, each taking hold of one wire of the coil with the free hand, a +sound proceeds from the clasped hands. The effect is not produced when +the hands are moist. When either of the two touches the body of the +other a loud sound comes from the parts in contact. When the arm of one +is placed against the arm of the other, the noise produced can be heard +at a distance of several feet. In all these cases a slight shock is +experienced so long as the contact is preserved. The introduction of a +piece of paper between the parts in contact does not materially +interfere with the production of the sounds, but the unpleasant effects +of the shock are avoided. + +[Illustration: Fig. 12] + +When an intermittent current from a Ruhmkorff's coil is passed through +the arms a musical note can be perceived when the ear is closely applied +to the arm of the person experimented upon. The sound seems to proceed +from the muscles of the fore-arm and from the biceps muscle. Mr. Elisha +Gray has also produced audible effects by the passage of electricity +through the human body. + +An extremely loud musical note is occasioned by the spark of a +Ruhmkorff's coil when the primary circuit is made and broken with +sufficient rapidity. When two breakers of different pitch are caused +simultaneously to open and close the primary circuit a double tone +proceeds from the spark. + +A curious discovery, which may be of interest to you, has been made by +Professor Blake. He constructed a telephone in which a rod of soft iron, +about six feet in length, was used instead of a permanent magnet. A +friend sang a continuous musical tone into the mouthpiece of a +telephone, like that shown in Fig. 12, which was connected with the soft +iron instrument alluded to above. It was found that the loudness of the +sound produced in this telephone varied with the direction in which the +iron rod was held, and that the maximum effect was produced when the rod +was in the position of the dipping needle. This curious discovery of +Professor Blake has been verified by myself. + +When a telephone is placed in circuit with a telegraph line the +telephone is found seemingly to emit sounds on its own account. The most +extraordinary noises are often produced, the causes of which are at +present very obscure. One class of sounds is produced by the inductive +influence of neighbouring wires and by leakage from them, the signals of +the Morse alphabet passing over neighbouring wires being audible in the +telephone, and another class can be traced to earth currents upon the +wire, a curious modification of this sound revealing the presence of +defective joints in the wire. + +Professor Blake informs me that he has been able to use the railroad +track for conversational purposes in place of a telegraph wire, and he +further states that when only one telephone was connected with the track +the sounds of Morse operating were distinctly audible in the telephone, +although the nearest telegraph wires were at least fifty feet distant. + +Professor Peirce has observed the most singular sounds produced from a +telephone in connection with a telegraph wire during the aurora +borealis, and I have just heard of a curious phenomenon lately observed +by Dr. Channing. In the city of Providence, Rhode Island, there is an +over-house wire about one mile in extent with a telephone at either end. +On one occasion the sound of music and singing was faintly audible in +one of the telephones. It seemed as if some one were practising vocal +music with a pianoforte accompaniment. The natural supposition was that +experiments were being made with the telephone at the other end of the +circuit, but upon inquiry this proved not to have been the case. +Attention having thus been directed to the phenomenon, a watch was kept +upon the instruments, and upon a subsequent occasion the same fact was +observed at both ends of the line by Dr. Channing and his friends. It +was proved that the sounds continued for about two hours, and usually +commenced about the same time. A searching examination of the line +disclosed nothing abnormal in its condition, and I am unable to give you +any explanation of this curious phenomenon. Dr. Channing has, however, +addressed a letter upon the subject to the editor of one of the +Providence papers, giving the names of such songs as were recognized, +and full details of the observations, in the hope that publicity may +lead to the discovery of the performer, and thus afford a solution of +the mystery. + +My friend, Mr. Frederick A. Gower, communicated to me a curious +observation made by him regarding the slight earth connection required +to establish a circuit for the telephone, and together we carried on a +series of experiments with rather startling results. We took a couple of +telephones and an insulated wire about 100 yards in length into a +garden, and were enabled to carry on conversation with the greatest ease +when we held in our hands what should have been the earth wire, so that +the connection with the ground was formed at either end through our +bodies, our feet being clothed with cotton socks and leather boots. The +day was fine, and the grass upon which we stood was seemingly perfectly +dry. Upon standing upon a gravel walk the vocal sounds, though much +diminished, were still perfectly intelligible, and the same result +occurred when standing upon a brick wall one foot in height, but no +sound was audible when one of us stood upon a block of freestone. + +One experiment which we made is so very interesting that I must speak of +it in detail. Mr. Gower made earth connection at his end of the line by +standing upon a grass plot, whilst at the other end of the line I stood +upon a wooden board. I requested Mr. Gower to sing a continuous musical +note, and to my surprise the sound was very distinctly audible from the +telephone in my hand. Upon examining my feet I discovered that a single +blade of grass was bent over the edge of the board, and that my foot +touched it. The removal of this blade of grass was followed by the +cessation of the sound from the telephone, and I found that the moment I +touched with the toe of my boot a blade of grass or the petal of a daisy +the sound was again audible. + +The question will naturally arise, Through what length of wire can the +telephone be used? In reply to this I may say that the maximum amount of +resistance through which the undulatory current will pass, and yet +retain sufficient force to produce an audible sound at the distant end, +has yet to be determined; no difficulty has, however, been experienced +in laboratory experiments in conversing through a resistance of 60,000 +ohms, which has been the maximum at my disposal. On one occasion, not +having a rheostat [for producing resistance] at hand, I passed the +current through the bodies of sixteen persons, who stood hand in hand. +The longest length of real telegraph line through which I have attempted +to converse has been about 250 miles. On this occasion no difficulty was +experienced so long as parallel lines were not in operation. Sunday was +chosen as the day on which it was probable other circuits would be at +rest. Conversation was carried on between myself, in New York, and Mr. +Thomas A. Watson, in Boston, until the opening of business upon the +other wires. When this happened the vocal sounds were very much +diminished, but still audible. It seemed, indeed, like talking through a +storm. Conversation, though possible, could be carried on with +difficulty, owing to the distracting nature of the interfering currents. + +I am informed by my friend Mr. Preece that conversation has been +successfully carried on through a submarine cable, sixty miles in +length, extending from Dartmouth to the Island of Guernsey, by means of +hand telephones. + + + + +PHOTOGRAPHING THE UNSEEN: THE ROENTGEN RAY + +H. J. W. DAM + + [By permission from _McClure's Magazine_, April, 1896, copyright by + S. S. McClure, Limited.] + + +In all the history of scientific discovery there has never been, +perhaps, so general, rapid, and dramatic an effect wrought on the +scientific centres of Europe as has followed, in the past four weeks, +upon an announcement made to the Wuerzburg Physico-Medical Society, at +their December [1895] meeting, by Professor William Konrad Roentgen, +professor of physics at the Royal University of Wuerzburg. The first news +which reached London was by telegraph from Vienna to the effect that a +Professor Roentgen, until then the possessor of only a local fame in the +town mentioned, had discovered a new kind of light, which penetrated and +photographed through everything. This news was received with a mild +interest, some amusement, and much incredulity; and a week passed. Then, +by mail and telegraph, came daily clear indications of the stir which +the discovery was making in all the great line of universities between +Vienna and Berlin. Then Roentgen's own report arrived, so cool, so +business-like, and so truly scientific in character, that it left no +doubt either of the truth or of the great importance of the preceding +reports. To-day, four weeks after the announcement, Roentgen's name is +apparently in every scientific publication issued this week in Europe; +and accounts of his experiments, of the experiments of others following +his method, and of theories as to the strange new force which he has +been the first to observe, fill pages of every scientific journal that +comes to hand. And before the necessary time elapses for this article to +attain publication in America, it is in all ways probable that the +laboratories and lecture-rooms of the United States will also be giving +full evidence of this contagious arousal of interest over a discovery so +strange that its importance cannot yet be measured, its utility be even +prophesied, or its ultimate effect upon long established scientific +beliefs be even vaguely foretold. + +The Roentgen rays are certain invisible rays resembling, in many +respects, rays of light, which are set free when a high-pressure +electric current is discharged through a vacuum tube. A vacuum tube is a +glass tube from which all the air, down to one-millionth of an +atmosphere, has been exhausted after the insertion of a platinum wire in +either end of the tube for connection with the two poles of a battery or +induction coil. When the discharge is sent through the tube, there +proceeds from the anode--that is, the wire which is connected with the +positive pole of the battery--certain bands of light, varying in colour +with the colour of the glass. But these are insignificant in comparison +with the brilliant glow which shoots from the cathode, or negative wire. +This glow excites brilliant phosphorescence in glass and many +substances, and these "cathode rays," as they are called, were observed +and studied by Hertz; and more deeply by his assistant, Professor +Lenard, Lenard having, in 1894, reported that the cathode rays would +penetrate thin films of aluminum, wood, and other substances, and +produce photographic results beyond. It was left, however, for Professor +Roentgen to discover that during the discharge quite other rays are set +free, which differ greatly from those described by Lenard as cathode +rays. The most marked difference between the two is the fact that +Roentgen rays are not deflected by a magnet, indicating a very essential +difference, while their range and penetrative power are incomparably +greater. In fact, all those qualities which have lent a sensational +character to the discovery of Roentgen's rays were mainly absent from +those of Lenard, to the end that, although Roentgen has not been working +in an entirely new field, he has by common accord been freely granted +all the honors of a great discovery. + +Exactly what kind of a force Professor Roentgen has discovered he does +not know. As will be seen below, he declines to call it a new kind of +light, or a new form of electricity. He has given it the name of the X +rays. Others speak of it as the Roentgen rays. Thus far its results only, +and not its essence, are known. In the terminology of science it is +generally called "a new mode of motion," or, in other words, a new +force. As to whether it is or not actually a force new to science, or +one of the known forces masquerading under strange conditions, weighty +authorities are already arguing. More than one eminent scientist has +already affected to see in it a key to the great mystery of the law of +gravity. All who have expressed themselves in print have admitted, with +more or less frankness, that, in view of Roentgen's discovery, science +must forthwith revise, possibly to a revolutionary degree, the long +accepted theories concerning the phenomena of light and sound. That the +X rays, in their mode of action, combine a strange resemblance to both +sound and light vibrations, and are destined to materially affect, if +they do not greatly alter, our views of both phenomena, is already +certain; and beyond this is the opening into a new and unknown field of +physical knowledge, concerning which speculation is already eager, and +experimental investigation already in hand, in London, Paris, Berlin, +and, perhaps, to a greater or less extent, in every well-equipped +physical laboratory in Europe. + +This is the present scientific aspect of the discovery. But, unlike most +epoch-making results from laboratories, this discovery is one which, to +a very unusual degree, is within the grasp of the popular and +non-technical imagination. Among the other kinds of matter which these +rays penetrate with ease is human flesh. That a new photography has +suddenly arisen which can photograph the bones, and, before long, the +organs of the human body; that a light has been found which can +penetrate, so as to make a photographic record, through everything from +a purse or a pocket to the walls of a room or a house, is news which +cannot fail to startle everybody. That the eye of the physician or +surgeon, long baffled by the skin, and vainly seeking to penetrate the +unfortunate darkness of the human body, is now to be supplemented by a +camera, making all the parts of the human body as visible, in a way, as +the exterior, appears certainly to be a greater blessing to humanity +than even the Listerian antiseptic system of surgery; and its benefits +must inevitably be greater than those conferred by Lister, great as the +latter have been. Already, in the few weeks since Roentgen's +announcement, the results of surgical operations under the new system +are growing voluminous. In Berlin, not only new bone fractures are being +immediately photographed, but joined fractures, as well, in order to +examine the results of recent surgical work. In Vienna, imbedded bullets +are being photographed, instead of being probed for, and extracted with +comparative ease. In London, a wounded sailor, completely paralyzed, +whose injury was a mystery, has been saved by the photographing of an +object imbedded in the spine, which, upon extraction, proved to be a +small knife-blade. Operations for malformations, hitherto obscure, but +now clearly revealed by the new photography, are already becoming +common, and are being reported from all directions. Professor Czermark +of Graz has photographed the living skull, denuded of flesh and hair, +and has begun the adaptation of the new photography to brain study. The +relation of the new rays to thought rays is being eagerly discussed in +what may be called the non-exact circles and journals; and all that +numerous group of inquirers into the occult, the believers in +clairvoyance, spiritualism, telepathy, and kindred orders of alleged +phenomena, are confident of finding in the new force long-sought facts +in proof of their claims. Professor Neusser in Vienna has photographed +gallstones in the liver of one patient (the stone showing snow-white in +the negative), and a stone in the bladder of another patient. His +results so far induce him to announce that all the organs of the human +body can, and will, shortly, be photographed. Lannelongue of Paris has +exhibited to the Academy of Science photographs of bones showing +inherited tuberculosis which had not otherwise revealed itself. Berlin +has already formed a society of forty for the immediate prosecution of +researches into both the character of the new force and its +physiological possibilities. In the next few weeks these strange +announcements will be trebled or quadrupled, giving the best evidence +from all quarters of the great future that awaits the Roentgen rays, and +the startling impetus to the universal search for knowledge that has +come at the close of the nineteenth century from the modest little +laboratory in the Pleicher Ring at Wuerzburg. + +The Physical Institute, Professor Roentgen's particular domain, is a +modest building of two stories and basement, the upper story +constituting his private residence, and the remainder of the building +being given over to lecture rooms, laboratories, and their attendant +offices. At the door I was met by an old serving-man of the idolatrous +order, whose pain was apparent when I asked for "Professor" Roentgen, and +he gently corrected me with "Herr Doctor Roentgen." As it was evident, +however, that we referred to the same person, he conducted me along a +wide, bare hall, running the length of the building, with blackboards +and charts on the walls. At the end he showed me into a small room on +the right. This contained a large table desk, and a small table by the +window, covered by photographs, while the walls held rows of shelves +laden with laboratory and other records. An open door led into a +somewhat larger room, perhaps twenty feet by fifteen, and I found myself +gazing into a laboratory which was the scene of the discovery--a +laboratory which, though in all ways modest, is destined to be +enduringly historical. + +There was a wide table shelf running along the farther side, in front of +the two windows, which were high, and gave plenty of light. In the +centre was a stove; on the left, a small cabinet whose shelves held the +small objects which the professor had been using. There was a table in +the left-hand corner; and another small table--the one on which living +bones were first photographed--was near the stove, and a Ruhmkorff coil +was on the right. The lesson of the laboratory was eloquent. Compared, +for instance, with the elaborate, expensive, and complete apparatus of, +say, the University of London, or of any of the great American +universities, it was bare and unassuming to a degree. It mutely said +that in the great march of science it is the genius of man, and not the +perfection of appliances, that breaks new ground in the great territory +of the unknown. It also caused one to wonder at and endeavour to imagine +the great things which are to be done through elaborate appliances with +the Roentgen rays--a field in which the United States, with its foremost +genius in invention, will very possibly, if not probably, take the +lead--when the discoverer himself had done so much with so little. +Already, in a few weeks, a skilled London operator, Mr. A. A. C. +Swinton, has reduced the necessary time of exposure for Roentgen +photographs from fifteen minutes to four. He used, however, a Tesla oil +coil, discharged by twelve half-gallon Leyden jars, with an alternating +current of twenty thousand volts' pressure. Here were no oil coils, +Leyden jars, or specially elaborate and expensive machines. There were +only a Ruhmkorff coil and Crookes (vacuum) tube and the man himself. + +Professor Roentgen entered hurriedly, something like an amiable gust of +wind. He is a tall, slender, and loose-limbed man, whose whole +appearance bespeaks enthusiasm and energy. He wore a dark blue sack +suit, and his long, dark hair stood straight up from his forehead, as if +he were permanently electrified by his own enthusiasm. His voice is full +and deep, he speaks rapidly, and, altogether, he seems clearly a man +who, once upon the track of a mystery which appealed to him, would +pursue it with unremitting vigor. His eyes are kind, quick, and +penetrating; and there is no doubt that he much prefers gazing at a +Crookes tube to beholding a visitor, visitors at present robbing him of +much valued time. The meeting was by appointment, however, and his +greeting was cordial and hearty. In addition to his own language he +speaks French well and English scientifically, which is different from +speaking it popularly. These three tongues being more or less within the +equipment of his visitor, the conversation proceeded on an international +or polyglot basis, so to speak, varying at necessity's demand. + +It transpired in the course of inquiry, that the professor is a married +man and fifty years of age, though his eyes have the enthusiasm of +twenty-five. He was born near Zurich, and educated there, and completed +his studies and took his degree at Utrecht. He has been at Wuerzburg +about seven years, and had made no discoveries which he considered of +great importance prior to the one under consideration. These details +were given under good-natured protest, he failing to understand why his +personality should interest the public. He declined to admire himself or +his results in any degree, and laughed at the idea of being famous. The +professor is too deeply interested in science to waste any time in +thinking about himself. His emperor had feasted, flattered, and +decorated him, and he was loyally grateful. It was evident, however, +that fame and applause had small attractions for him, compared to the +mysteries still hidden in the vacuum tubes of the other room. + +"Now, then," said he, smiling, and with some impatience, when the +preliminary questions at which he chafed were over, "you have come to +see the invisible rays." + +"Is the invisible visible?" + +"Not to the eye; but its results are. Come in here." + +[Illustration: BONES OF A HUMAN FOOT PHOTOGRAPHED THROUGH THE FLESH + +From a photograph by A. A. C. Swinton, Victoria Street, London. +Exposure, fifty-five seconds] + +He led the way to the other square room mentioned, and indicated the +induction coil with which his researches were made, an ordinary +Ruhmkorff coil, with a spark of from four to six inches, charged by a +current of twenty amperes. Two wires led from the coil, through an open +door, into a smaller room on the right. In this room was a small table +carrying a Crookes tube connected with the coil. The most striking +object in the room, however, was a huge and mysterious tin box about +seven feet high and four feet square. It stood on end, like a huge +packing case, its side being perhaps five inches from the Crookes tube. + +The professor explained the mystery of the tin box, to the effect that +it was a device of his own for obtaining a portable dark-room. When he +began his investigations he used the whole room, as was shown by the +heavy blinds and curtains so arranged as to exclude the entrance of all +interfering light from the windows. In the side of the tin box, at the +point immediately against the tube, was a circular sheet of aluminum one +millimetre in thickness, and perhaps eighteen inches in diameter, +soldered to the surrounding tin. To study his rays the professor had +only to turn on the current, enter the box, close the door, and in +perfect darkness inspect only such light or light effects as he had a +right to consider his own, hiding his light, in fact, not under the +Biblical bushel, but in a more commodious box. + +"Step inside," said he, opening the door, which was on the side of the +box farthest from the tube. I immediately did so, not altogether certain +whether my skeleton was to be photographed for general inspection, or my +secret thoughts held up to light on a glass plate. "You will find a +sheet of barium paper on the shelf," he added, and then went away to the +coil. The door was closed, and the interior of the box became black +darkness. The first thing I found was a wooden stool, on which I +resolved to sit. Then I found the shelf on the side next the tube, and +then the sheet of paper prepared with barium platinocyanide. I was thus +being shown the first phenomenon which attracted the discoverer's +attention and led to his discovery, namely, the passage of rays, +themselves wholly invisible, whose presence was only indicated by the +effect they produced on a piece of sensitized photographic paper. + +A moment later, the black darkness was penetrated by the rapid snapping +sound of the high-pressure current in action, and I knew that the tube +outside was glowing. I held the sheet vertically on the shelf, perhaps +four inches from the plate. There was no change, however, and nothing +was visible. + +"Do you see anything?" he called. + +"No." + +"The tension is not high enough;" and he proceeded to increase the +pressure by operating an apparatus of mercury in long vertical tubes +acted upon automatically by a weight lever which stood near the coil. In +a few moments the sound of the discharge again began, and then I made my +first acquaintance with the Roentgen rays. + +The moment the current passed, the paper began to glow. A yellowish +green light spread all over its surface in clouds, waves and flashes. +The yellow-green luminescence, all the stranger and stronger in the +darkness, trembled, wavered, and floated over the paper, in rhythm with +the snapping of the discharge. Through the metal plate, the paper, +myself, and the tin box, the invisible rays were flying, with an effect +strange, interesting and uncanny. The metal plate seemed to offer no +appreciable resistance to the flying force, and the light was as rich +and full as if nothing lay between the paper and the tube. + +"Put the book up," said the professor. + +I felt upon the shelf, in the darkness, a heavy book, two inches in +thickness, and placed this against the plate. It made no difference. The +rays flew through the metal and the book as if neither had been there, +and the waves of light, rolling cloud-like over the paper, showed no +change in brightness. It was a clear, material illustration of the ease +with which paper and wood are penetrated. And then I laid book and paper +down, and put my eyes against the rays. All was blackness, and I neither +saw nor felt anything. The discharge was in full force, and the rays +were flying through my head, and, for all I knew, through the side of +the box behind me. But they were invisible and impalpable. They gave no +sensation whatever. Whatever the mysterious rays may be, they are not to +be seen, and are to be judged only by their works. + +I was loath to leave this historical tin box, but time pressed. I +thanked the professor, who was happy in the reality of his discovery and +the music of his sparks. Then I said: "Where did you first photograph +living bones?" + +"Here," he said, leading the way into the room where the coil stood. He +pointed to a table on which was another--the latter a small +short-legged wooden one with more the shape and size of a wooden seat. +It was two feet square and painted coal black. I viewed it with +interest. I would have bought it, for the little table on which light +was first sent through the human body will some day be a great +historical curiosity; but it was not for sale. A photograph of it would +have been a consolation, but for several reasons one was not to be had +at present. However, the historical table was there, and was duly +inspected. + +"How did you take the first hand photograph?" I asked. + +The professor went over to a shelf by the window, where lay a number of +prepared glass plates, closely wrapped in black paper. He put a Crookes +tube underneath the table, a few inches from the under side of its top. +Then he laid his hand flat on the top of the table, and placed the glass +plate loosely on his hand. + +"You ought to have your portrait painted in that attitude," I suggested. + +"No, that is nonsense," said he, smiling. + +"Or be photographed." This suggestion was made with a deeply hidden +purpose. + +The rays from the Roentgen eyes instantly penetrated the deeply hidden +purpose. "Oh, no," said he; "I can't let you make pictures of me. I am +too busy." Clearly the professor was entirely too modest to gratify the +wishes of the curious world. + +"Now, Professor," said I, "will you tell me the history of the +discovery?" + +"There is no history," he said. "I have been for a long time interested +in the problem of the cathode rays from a vacuum tube as studied by +Hertz and Lenard. I had followed their and other researches with great +interest, and determined, as soon as I had the time, to make some +researches of my own. This time I found at the close of last October. I +had been at work for some days when I discovered something new." + +"What was the date?" + +"The eighth of November." + +"And what was the discovery?" + +"I was working with a Crookes tube covered by a shield of black +cardboard. A piece of barium platinocyanide paper lay on the bench +there. I had been passing a current through the tube, and I noticed a +peculiar black line across the paper." + +"What of that?" + +"The effect was one which could only be produced, in ordinary parlance, +by the passage of light. No light could come from the tube, because the +shield which covered it was impervious to any light known, even that of +the electric arc." + +"And what did you think?" + +"I did not think; I investigated. I assumed that the effect must have +come from the tube, since its character indicated that it could come +from nowhere else. I tested it. In a few minutes there was no doubt +about it. Rays were coming from the tube which had a luminescent effect +upon the paper. I tried it successfully at greater and greater +distances, even at two metres. It seemed at first a new kind of +invisible light. It was clearly something new, something unrecorded." + +"Is it light?" + +"No." + +"Is it electricity?" + +"Not in any known form." + +"What is it?" + +"I don't know." + +And the discoverer of the X rays thus stated as calmly his ignorance of +their essence as has everybody else who has written on the phenomena +thus far. + +"Having discovered the existence of a new kind of rays, I of course +began to investigate what they would do." He took up a series of +cabinet-sized photographs. "It soon appeared from tests that the rays +had penetrative powers to a degree hitherto unknown. They penetrated +paper, wood, and cloth with ease; and the thickness of the substance +made no perceptible difference, within reasonable limits." He showed +photographs of a box of laboratory weights of platinum, aluminum, and +brass, they and the brass hinges all having been photographed from a +closed box, without any indication of the box. Also a photograph of a +coil of fine wire, wound on a wooden spool, the wire having been +photographed, and the wood omitted. "The rays," he continued, "passed +through all the metals tested, with a facility varying, roughly +speaking, with the density of the metal. These phenomena I have +discussed carefully in my report to the Wuerzburg society, and you will +find all the technical results therein stated." He showed a photograph +of a small sheet of zinc. This was composed of smaller plates soldered +laterally with solders of different metallic proportions. The differing +lines of shadow, caused by the difference in the solders, were visible +evidence that a new means of detecting flaws and chemical variations in +metals had been found. A photograph of a compass showed the needle and +dial taken through the closed brass cover. The markings of the dial were +in red metallic paint, and thus interfered with the rays, and were +reproduced. "Since the rays had this great penetrative power, it seemed +natural that they should penetrate flesh, and so it proved in +photographing the hand, as I showed you." + +A detailed discussion of the characteristics of his rays the professor +considered unprofitable and unnecessary. He believes, though, that these +mysterious radiations are not light, because their behaviour is +essentially different from that of light rays, even those light rays +which are themselves invisible. The Roentgen rays cannot be reflected by +reflecting surfaces, concentrated by lenses, or refracted or diffracted. +They produce photographic action on a sensitive film, but their action +is weak as yet, and herein lies the first important field of their +development. The professor's exposures were comparatively long--an +average of fifteen minutes in easily penetrable media, and half an hour +or more in photographing the bones of the hand. Concerning vacuum tubes, +he said that he preferred the Hittorf, because it had the most perfect +vacuum, the highest degree of air exhaustion being the consummation most +desirable. In answer to a question, "What of the future?" he said: + +"I am not a prophet, and I am opposed to prophesying. I am pursuing my +investigations, and as fast as my results are verified I shall make them +public." + +"Do you think the rays can be so modified as to photograph the organs of +the human body?" + +In answer he took up the photograph of the box of weights. "Here are +already modifications," he said, indicating the various degrees of +shadow produced by the aluminum, platinum, and brass weights, the brass +hinges, and even the metallic stamped lettering on the cover of the box, +which was faintly perceptible. + +"But Professor Neusser has already announced that the photographing of +the various organs is possible." + +"We shall see what we shall see," he said. "We have the start now; the +development will follow in time." + +"You know the apparatus for introducing the electric light into the +stomach?" + +"Yes." + +"Do you think that this electric light will become a vacuum tube for +photographing, from the stomach, any part of the abdomen or thorax?" + +The idea of swallowing a Crookes tube, and sending a high frequency +current down into one's stomach, seemed to him exceedingly funny. "When +I have done it, I will tell you," he said, smiling, resolute in abiding +by results. + +"There is much to do, and I am busy, very busy," he said in conclusion. +He extended his hand in farewell, his eyes already wandering toward his +work in the inside room. And his visitor promptly left him; the words, +"I am busy," said in all sincerity, seeming to describe in a single +phrase the essence of his character and the watchword of a very unusual +man. + +Returning by way of Berlin, I called upon Herr Spies of the Urania, +whose photographs after the Roentgen method were the first made public, +and have been the best seen thus far. In speaking of the discovery he +said: + +"I applied it, as soon as the penetration of flesh was apparent, to the +photograph of a man's hand. Something in it had pained him for years, +and the photograph at once exhibited a small foreign object, as you can +see;" and he exhibited a copy of the photograph in question. "The speck +there is a small piece of glass, which was immediately extracted, and +which, in all probability, would have otherwise remained in the man's +hand to the end of his days." All of which indicates that the needle +which has pursued its travels in so many persons, through so many years, +will be suppressed by the camera. + +"My next object is to photograph the bones of the entire leg," continued +Herr Spies. "I anticipate no difficulty, though it requires some thought +in manipulation." + +It will be seen that the Roentgen rays and their marvellous practical +possibilities are still in their infancy. The first successful +modification of the action of the rays so that the varying densities of +bodily organs will enable them to be photographed will bring all such +morbid growths as tumours and cancers into the photographic field, to +say nothing of vital organs which may be abnormally developed or +degenerate. How much this means to medical and surgical practice it +requires little imagination to conceive. Diagnosis, long a painfully +uncertain science, has received an unexpected and wonderful assistant; +and how greatly the world will benefit thereby, how much pain will be +saved, only the future can determine. In science a new door has been +opened where none was known to exist, and a side-light on phenomena has +appeared, of which the results may prove as penetrating and astonishing +as the Roentgen rays themselves. The most agreeable feature of the +discovery is the opportunity it gives for other hands to help; and the +work of these hands will add many new words to the dictionaries, many +new facts to science, and, in the years long ahead of us, fill many more +volumes than there are paragraphs in this brief and imperfect account. + + + + +THE WIRELESS TELEGRAPH + +GEORGE ILES + + [From "Flame, Electricity and the Camera," copyright by Doubleday, + Page & Co., New York.] + + +In a series of experiments interesting enough but barren of utility, the +water of a canal, river, or bay has often served as a conductor for the +telegraph. Among the electricians who have thus impressed water into +their service was Professor Morse. In 1842 he sent a few signals across +the channel from Castle Garden, New York, to Governor's Island, a +distance of a mile. With much better results, he sent messages, later in +the same year, from one side of the canal at Washington to the other, a +distance of eighty feet, employing large copper plates at each terminal. +The enormous current required to overcome the resistance of water has +barred this method from practical adoption. + +We pass, therefore, to electrical communication as effected by +induction--the influence which one conductor exerts on another through +an intervening insulator. At the outset we shall do well to bear in mind +that magnetic phenomena, which are so closely akin to electrical, are +always inductive. To observe a common example of magnetic induction, we +have only to move a horseshoe magnet in the vicinity of a compass +needle, which will instantly sway about as if blown hither and thither +by a sharp draught of air. This action takes place if a slate, a pane of +glass, or a shingle is interposed between the needle and its perturber. +There is no known insulator for magnetism, and an induction of this kind +exerts itself perceptibly for many yards when large masses of iron are +polarised, so that the derangement of compasses at sea from moving iron +objects aboard ship, or from ferric ores underlying a sea-coast, is a +constant peril to the mariner. + +Electrical conductors behave much like magnetic masses. A current +conveyed by a conductor induces a counter-current in all surrounding +bodies, and in a degree proportioned to their conductive power. This +effect is, of course, greatest upon the bodies nearest at hand, and we +have already remarked its serious retarding effect in ocean telegraphy. +When the original current is of high intensity, it can induce a +perceptible current in another wire at a distance of several miles. In +1842 Henry remarked that electric waves had this quality, but in that +early day of electrical interpretation the full significance of the fact +eluded him. In the top room of his house he produced a spark an inch +long, which induced currents in wires stretched in his cellar, through +two thick floors and two rooms which came between. Induction of this +sort causes the annoyance, familiar in single telephonic circuits, of +being obliged to overhear other subscribers, whose wires are often far +away from our own. + +The first practical use of induced currents in telegraphy was when Mr. +Edison, in 1885, enabled the trains on a line of the Staten Island +Railroad to be kept in constant communication with a telegraphic wire, +suspended in the ordinary way beside the track. The roof of a car was of +insulated metal, and every tap of an operator's key within the walls +electrified the roof just long enough to induce a brief pulse through +the telegraphic circuit. In sending a message to the car this wire was, +moment by moment, electrified, inducing a response first in the car +roof, and next in the "sounder" beneath it. This remarkable apparatus, +afterward used on the Lehigh Valley Railroad, was discontinued from lack +of commercial support, although it would seem to be advantageous to +maintain such a service on other than commercial grounds. In case of +chance obstructions on the track, or other peril, to be able to +communicate at any moment with a train as it speeds along might mean +safety instead of disaster. The chief item in the cost of this system is +the large outlay for a special telegraphic wire. + +The next electrician to employ induced currents in telegraphy was Mr. +(now Sir) William H. Preece, the engineer then at the head of the +British telegraph system. Let one example of his work be cited. In 1896 +a cable was laid between Lavernock, near Cardiff, on the Bristol +Channel, and Flat Holme, an island three and a third miles off. As the +channel at this point is a much-frequented route and anchor ground, the +cable was broken again and again. As a substitute for it Mr. Preece, in +1898, strung wires along the opposite shores, and found that an electric +pulse sent through one wire instantly made itself heard in a telephone +connected with the other. It would seem that in this etheric form of +telegraphy the two opposite lines of wire must be each as long as the +distance which separates them; therefore, to communicate across the +English Channel from Dover to Calais would require a line along each +coast at least twenty miles in length. Where such lines exist for +ordinary telegraphy, they might easily lend themselves to the Preece +system of signalling in case a submarine cable were to part. + +Marconi, adopting electrostatic instead of electro-magnetic waves, has +won striking results. Let us note the chief of his forerunners, as they +prepared the way for him. In 1864 Maxwell observed that electricity and +light have the same velocity, 186,400 miles a second, and he formulated +the theory that electricity propagates itself in waves which differ from +those of light only in being longer. This was proved to be true by +Hertz, who in 1888 showed that where alternating currents of very high +frequency were set up in an open circuit, the energy might be conveyed +entirely away from the circuit into the surrounding space as electric +waves. His detector was a nearly closed circle of wire, the ends being +soldered to metal balls almost in contact. With this simple apparatus he +demonstrated that electric waves move with the speed of light, and that +they can be reflected and refracted precisely as if they formed a +visible beam. At a certain intensity of strain the air insulation broke +down, and the air became a conductor. This phenomenon of passing quite +suddenly from a non-conductive to a conductive state is, as we shall +duly see, also to be noted when air or other gases are exposed to the X +ray. + +Now for the effect of electric waves such as Hertz produced, when they +impinge upon substances reduced to powder or filings. Conductors, such +as the metals, are of inestimable service to the electrician; of equal +value are non-conductors, such as glass and gutta-percha, as they +strictly fence in an electric stream. A third and remarkable vista opens +to experiment when it deals with substances which, in their normal +state, are non-conductive, but which, agitated by an electric wave, +instantly become conductive in a high degree. As long ago as 1866 Mr. S. +A. Varley noticed that black lead, reduced to a loose dust, effectually +intercepted a current from fifty Daniell cells, although the battery +poles were very near each other. When he increased the electric tension +four- to six-fold, the black-lead particles at once compacted themselves +so as to form a bridge of excellent conductivity. On this principle he +invented a lightning-protector for electrical instruments, the incoming +flash causing a tiny heap of carbon dust to provide it with a path +through which it could safely pass to the earth. Professor Temistocle +Calzecchi Onesti of Fermo, in 1885, in an independent series of +researches, discovered that a mass of powdered copper is a non-conductor +until an electric wave beats upon it; then, in an instant, the mass +resolves itself into a conductor almost as efficient as if it were a +stout, unbroken wire. Professor Edouard Branly of Paris, in 1891, on +this principle devised a coherer, which passed from resistance to +invitation when subjected to an electric impulse from afar. He enhanced +the value of his device by the vital discovery that the conductivity +bestowed upon filings by electric discharges could be destroyed by +simply shaking or tapping them apart. + +In a homely way the principle of the coherer is often illustrated in +ordinary telegraphic practice. An operator notices that his instrument +is not working well, and he suspects that at some point in his circuit +there is a defective contact. A little dirt, or oxide, or dampness, has +come in between two metallic surfaces; to be sure, they still touch each +other, but not in the firm and perfect way demanded for his work. +Accordingly he sends a powerful current abruptly into the line, which +clears its path thoroughly, brushes aside dirt, oxide, or moisture, and +the circuit once more is as it should be. In all likelihood, the coherer +is acted upon in the same way. Among the physicists who studied it in +its original form was Dr. Oliver J. Lodge. He improved it so much that, +in 1894, at the Royal Institution in London, he was able to show it as +an electric eye that registered the impact of invisible rays at a +distance of more than forty yards. He made bold to say that this +distance might be raised to half a mile. + +As early as 1879 Professor D. E. Hughes began a series of experiments in +wireless telegraphy, on much the lines which in other hands have now +reached commercial as well as scientific success. Professor Hughes was +the inventor of the microphone, and that instrument, he declared, +affords an unrivalled means of receiving wireless messages, since it +requires no tapping to restore its non-conductivity. In his researches +this investigator was convinced that his signals were propagated, not by +electro-magnetic induction, but by aerial electric waves spreading out +from an electric spark. Early in 1880 he showed his apparatus to +Professor Stokes, who observed its operation carefully. His dictum was +that he saw nothing which could not be explained by known +electro-magnetic effects. This erroneous judgment so discouraged +Professor Hughes that he desisted from following up his experiments, and +thus, in all probability, the birth of the wireless telegraph was for +several years delayed.[3] + +[Illustration: Fig. 71.--Marconi coherer, enlarged view] + +The coherer, as improved by Marconi, is a glass tube about one and +one-half inches long and about one-twelfth of an inch in internal +diameter. The electrodes are inserted in this tube so as almost to +touch; between them is about one-thirtieth of an inch filled with a +pinch of the responsive mixture which forms the pivot of the whole +contrivance. This mixture is 90 per cent. nickel filings, 10 per cent. +hard silver filings, and a mere trace of mercury; the tube is exhausted +of air to within one ten-thousandth part (Fig. 71). How does this trifle +of metallic dust manage loudly to utter its signals through a +telegraphic sounder, or forcibly indent them upon a moving strip of +paper? Not directly, but indirectly, as the very last refinement of +initiation. Let us imagine an ordinary telegraphic battery strong enough +loudly to tick out a message. Be it ever so strong it remains silent +until its circuit is completed, and for that completion the merest touch +suffices. Now the thread of dust in the coherer forms part of such a +telegraphic circuit: as loose dust it is an effectual bar and obstacle, +under the influence of electric waves from afar it changes instantly to +a coherent metallic link which at once completes the circuit and +delivers the message. + +An electric impulse, almost too attenuated for computation, is here able +to effect such a change in a pinch of dust that it becomes a free avenue +instead of a barricade. Through that avenue a powerful blow from a local +store of energy makes itself heard and felt. No device of the trigger +class is comparable with this in delicacy. An instant after a signal has +taken its way through the coherer a small hammer strikes the tiny tube, +jarring its particles asunder, so that they resume their normal state of +high resistance. We may well be astonished at the sensitiveness of the +metallic filings to an electric wave originating many miles away, but +let us remember how clearly the eye can see a bright lamp at the same +distance as it sheds a sister beam. Thus far no substance has been +discovered with a mechanical responsiveness to so feeble a ray of light; +in the world of nature and art the coherer stands alone. The electric +waves employed by Marconi are about four feet long, or have a frequency +of about 250,000,000 per second. Such undulations pass readily through +brick or stone walls, through common roofs and floors--indeed, through +all substances which are non-conductive to electric waves of ordinary +length. Were the energy of a Marconi sending-instrument applied to an +arc-lamp, it would generate a beam of a thousand candle-power. We have +thus a means of comparing the sensitiveness of the retina to light with +the responsiveness of the Marconi coherer to electric waves, after both +radiations have undergone a journey of miles. + +An essential feature of this method of etheric telegraphy, due to +Marconi himself, is the suspension of a perpendicular wire at each +terminus, its length twenty feet for stations a mile apart, forty feet +for four miles, and so on, the telegraphic distance increasing as the +square of the length of suspended wire. In the Kingstown regatta, July, +1898, Marconi sent from a yacht under full steam a report to the shore +without the loss of a moment from start to finish. This feat was +repeated during the protracted contest between the _Columbia_ and the +_Shamrock_ yachts in New York Bay, October, 1899. On March 28, 1899, +Marconi signals put Wimereux, two miles north of Boulogne, in +communication with the South Foreland Lighthouse, thirty-two miles +off.[4] In August, 1899, during the manoeuvres of the British navy, +similar messages were sent as far as eighty miles. It was clearly +demonstrated that a new power had been placed in the hands of a naval +commander. "A touch on a button in a flagship is all that is now needed +to initiate every tactical evolution in a fleet, and insure an almost +automatic precision in the resulting movements of the ships. The +flashing lantern is superseded at night, flags and the semaphore by day, +or, if these are retained, it is for services purely auxiliary. The +hideous and bewildering shrieks of the steam-siren need no longer be +heard in a fog, and the uncertain system of gun signals will soon become +a thing of the past." The interest of the naval and military strategist +in the Marconi apparatus extends far beyond its communication of +intelligence. Any electrical appliance whatever may be set in motion by +the same wave that actuates a telegraphic sounder. A fuse may be +ignited, or a motor started and directed, by apparatus connected with +the coherer, for all its minuteness. Mr. Walter Jamieson and Mr. John +Trotter have devised means for the direction of torpedoes by ether +waves, such as those set at work in the wireless telegraph. Two rods +projecting above the surface of the water receive the waves, and are in +circuit with a coherer and a relay. At the will of the distant operator +a hollow wire coil bearing a current draws in an iron core either to the +right or to the left, moving the helm accordingly. + +As the news of the success of the Marconi telegraph made its way to the +London Stock Exchange there was a fall in the shares of cable companies. +The fear of rivalry from the new invention was baseless. As but fifteen +words a minute are transmissible by the Marconi system, it evidently +does not compete with a cable, such as that between France and England, +which can transmit 2,500 words a minute without difficulty. The Marconi +telegraph comes less as a competitor to old systems than as a mode of +communication which creates a field of its own. We have seen what it may +accomplish in war, far outdoing any feat possible to other apparatus, +acoustic, luminous, or electrical. In quite as striking fashion does it +break new ground in the service of commerce and trade. It enables +lighthouses continually to spell their names, so that receivers aboard +ship may give the steersmen their bearings even in storm and fog. In the +crowded condition of the steamship "lanes" which cross the Atlantic, a +priceless security against collision is afforded the man at the helm. +On November 15, 1899, Marconi telegraphed from the American liner _St. +Paul_ to the Needles, sixty-six nautical miles away. On December 11 and +12, 1901, he received wireless signals near St. John's, Newfoundland, +sent from Poldhu, Cornwall, England, or a distance of 1,800 miles,--a +feat which astonished the world. In many cases the telegraphic business +to an island is too small to warrant the laying of a cable; hence we +find that Trinidad and Tobago are to be joined by the wireless system, +as also five islands of the Hawaiian group, eight to sixty-one miles +apart. + +A weak point in the first Marconi apparatus was that anybody within the +working radius of the sending-instrument could read its messages. To +modify this objection secret codes were at times employed, as in +commerce and diplomacy. A complete deliverance from this difficulty is +promised in attuning a transmitter and a receiver to the same note, so +that one receiver, and no other, shall respond to a particular frequency +of impulses. The experiments which indicate success in this vital +particular have been conducted by Professor Lodge. + +When electricians, twenty years ago, committed energy to a wire and thus +enabled it to go round a corner, they felt that they had done well. The +Hertz waves sent abroad by Marconi ask no wire, as they find their way, +not round a corner, but through a corner. On May 1, 1899, a party of +French officers on board the _Ibis_ at Sangatte, near Calais, spoke to +Wimereux by means of a Marconi apparatus, with Cape Grisnez, a lofty +promontory, intervening. In ascertaining how much the earth and the sea +may obstruct the waves of Hertz there is a broad and fruitful field for +investigation. "It may be," says Professor John Trowbridge, "that such +long electrical waves roll around the surface of such obstructions very +much as waves of sound and of water would do." + +[Illustration: Fig. 73--Discontinuous electric waves] + +[Illustration: Fig. 74--Wehnelt interrupter] + +It is singular how discoveries sometimes arrive abreast of each other so +as to render mutual aid, or supply a pressing want almost as soon as it +is felt. The coherer in its present form is actuated by waves of +comparatively low frequency, which rise from zero to full height in +extremely brief periods, and are separated by periods decidedly longer +(Fig. 73). What is needed is a plan by which the waves may flow either +continuously or so near together that they may lend themselves to +attuning. Dr. Wehnelt, by an extraordinary discovery, may, in all +likelihood, provide the lacking device in the form of his interrupter, +which breaks an electric circuit as often as two thousand times a +second. The means for this amazing performance are simplicity itself +(Fig. 74). A jar, _a_, containing a solution of sulphuric acid has two +electrodes immersed in it; one of them is a lead plate of large surface, +_b_; the other is a small platinum wire which protrudes from a glass +tube, _d_. A current passing through the cell between the two metals at +_c_ is interrupted, in ordinary cases five hundred times a second, and +in extreme cases four times as often, by bubbles of gas given off from +the wire instant by instant. + + +FOOTNOTES: + +[3] "History of the Wireless Telegraph," by J. J. Fahie. Edinburgh and +London, William Blackwood & Sons; New York, Dodd, Mead & Co., 1899. This +work is full of interesting detail, well illustrated. + +[4] The value of wireless telegraphy in relation to disasters at sea was +proved in a remarkable way yesterday morning. While the Channel was +enveloped in a dense fog, which had lasted throughout the greater part +of the night, the East Goodwin Lightship had a very narrow escape from +sinking at her moorings by being run into by the steamship _R. F. +Matthews_, 1,964 tons gross burden, of London, outward bound from the +Thames. The East Goodwin Lightship is one of four such vessels marking +the Goodwin Sands, and, curiously enough, it happens to be the one ship +which has been fitted out with Signor Marconi's installation for +wireless telegraphy. The vessel was moored about twelve miles to the +northeast of the South Foreland Lighthouse (where there is another +wireless-telegraphy installation), and she is about ten miles from the +shore, being directly opposite Deal. The information regarding the +collision was at once communicated by wireless telegraphy from the +disabled lightship to the South Foreland Lighthouse, where Mr. Bullock, +assistant to Signor Marconi, received the following message: "We have +just been run into by the steamer _R. F. Matthews_ of London. Steamship +is standing by us. Our bows very badly damaged." Mr. Bullock immediately +forwarded this information to the Trinity House authorities at +Ramsgate.--_Times_, April 29, 1899. + + + + +ELECTRICITY, WHAT ITS MASTERY MEANS: WITH A REVIEW AND A PROSPECT + +GEORGE ILES + + [From "Flame, Electricity and the Camera," copyright by Doubleday, + Page & Co., New York.] + + +With the mastery of electricity man enters upon his first real +sovereignty of nature. As we hear the whirr of the dynamo or listen at +the telephone, as we turn the button of an incandescent lamp or travel +in an electromobile, we are partakers in a revolution more swift and +profound than has ever before been enacted upon earth. Until the +nineteenth century fire was justly accounted the most useful and +versatile servant of man. To-day electricity is doing all that fire ever +did, and doing it better, while it accomplishes uncounted tasks far +beyond the reach of flame, however ingeniously applied. We may thus +observe under our eyes just such an impetus to human intelligence and +power as when fire was first subdued to the purposes of man, with the +immense advantage that, whereas the subjugation of fire demanded ages of +weary and uncertain experiment, the mastery of electricity is, for the +most part, the assured work of the nineteenth century, and, in truth, +very largely of its last three decades. The triumphs of the electrician +are of absorbing interest in themselves, they bear a higher significance +to the student of man as a creature who has gradually come to be what he +is. In tracing the new horizons won by electric science and art, a beam +of light falls on the long and tortuous paths by which man rose to his +supremacy long before the drama of human life had been chronicled or +sung. + +Of the strides taken by humanity on its way to the summit of terrestrial +life, there are but four worthy of mention as preparing the way for the +victories of the electrician--the attainment of the upright attitude, +the intentional kindling of fire, the maturing of emotional cries to +articulate speech, and the invention of written symbols for speech. As +we examine electricity in its fruitage we shall find that it bears the +unfailing mark of every other decisive factor of human advance: its +mastery is no mere addition to the resources of the race, but a +multiplier of them. The case is not as when an explorer discovers a +plant hitherto unknown, such as Indian corn, which takes its place +beside rice and wheat as a new food, and so measures a service which +ends there. Nor is it as when a prospector comes upon a new metal, such +as nickel, with the sole effect of increasing the variety of materials +from which a smith may fashion a hammer or a blade. Almost infinitely +higher is the benefit wrought when energy in its most useful phase is, +for the first time, subjected to the will of man, with dawning knowledge +of its unapproachable powers. It begins at once to marry the resources +of the mechanic and the chemist, the engineer and the artist, with issue +attested by all its own fertility, while its rays reveal province after +province undreamed of, and indeed unexisting, before its advent. + +Every other primal gift of man rises to a new height at the bidding of +the electrician. All the deftness and skill that have followed from the +upright attitude, in its creation of the human hand, have been brought +to a new edge and a broader range through electric art. Between the uses +of flame and electricity have sprung up alliances which have created new +wealth for the miner and the metal-worker, the manufacturer and the +shipmaster, with new insights for the man of research. Articulate speech +borne on electric waves makes itself heard half-way across America, and +words reduced to the symbols of symbols--expressed in the perforations +of a strip of paper--take flight through a telegraph wire at twenty-fold +the pace of speech. Because the latest leap in knowledge and faculty has +been won by the electrician, he has widened the scientific outlook +vastly more than any explorer who went before. Beyond any predecessor, +he began with a better equipment and a larger capital to prove the +gainfulness which ever attends the exploiting a supreme agent of +discovery. + +As we trace a few of the unending interlacements of electrical science +and art with other sciences and arts, and study their mutually +stimulating effects, we shall be reminded of a series of permutations +where the latest of the factors, because latest, multiplies all prior +factors in an unexampled degree.[5] We shall find reason to believe that +this is not merely a suggestive analogy, but really true as a tendency, +not only with regard to man's gains by the conquest of electricity, but +also with respect to every other signal victory which has brought him to +his present pinnacle of discernment and rule. If this permutative +principle in former advances lay undetected, it stands forth clearly in +that latest accession to skill and interpretation which has been ushered +in by Franklin and Volta, Faraday and Henry. + +Although of much less moment than the triumphs of the electrician, the +discovery of photography ranks second in importance among the scientific +feats of the nineteenth century. The camera is an artificial eye with +almost every power of the human retina, and with many that are denied +to vision--however ingeniously fortified by the lens-maker. A brief +outline of photographic history will show a parallel to the permutative +impulse so conspicuous in the progress of electricity. At the points +where the electrician and the photographer collaborate we shall note +achievements such as only the loftiest primal powers may evoke. + +A brief story of what electricity and its necessary precursor, fire, +have done and promise to do for civilization, may have attraction in +itself; so, also, may a review, though most cursory, of the work of the +camera and all that led up to it: for the provinces here are as wide as +art and science, and their bounds comprehend well-nigh the entirety of +human exploits. And between the lines of this story we may read +another--one which may tell us something of the earliest stumblings in +the dawn of human faculty. When we compare man and his next of kin, we +find between the two a great gulf, surely the widest betwixt any allied +families in nature. Can a being of intellect, conscience, and aspiration +have sprung at any time, however remote, from the same stock as the +orang and the chimpanzee? Since 1859, when Darwin published his "Origin +of Species," the theory of evolution has become so generally accepted +that to-day it is little more assailed than the doctrine of gravitation. +And yet, while the average man of intelligence bows to the formula that +all which now exists has come from the simplest conceivable state of +things,--a universal nebula, if you will,--in his secret soul he makes +one exception--himself. That there is a great deal more assent than +conviction in the world is a chiding which may come as justly from the +teacher's table as from the preacher's pulpit. Now, if we but catch the +meaning of man's mastery of electricity, we shall have light upon his +earlier steps as a fire-kindler, and as a graver of pictures and symbols +on bone and rock. As we thus recede from civilization to primeval +savagery, the process of the making of man may become so clear that the +arguments of Darwin shall be received with conviction, and not with +silent repulse. + +As we proceed to recall, one by one, the salient chapters in the history +of fire, and of the arts of depiction that foreran the camera, we shall +perceive a truth of high significance. We shall see that, while every +new faculty has its roots deep in older powers, and while its growth may +have been going on for age after age, yet its flowering may be as the +event of a morning. Even as our gardens show us the century-plants, once +supposed to bloom only at the end of a hundred years, so history, in the +large, exhibits discoveries whose harvests are gathered only after the +lapse of aeons instead of years. The arts of fire were slowly elaborated +until man had produced the crucible and the still, through which his +labours culminated in metals purified, in acids vastly more corrosive +than those of vegetation, in glass and porcelain equally resistant to +flame and the electric wave. These were combined in an hour by Volta to +build his cell, and in that hour began a new era for human faculty and +insight. + +It is commonly imagined that the progress of humanity has been at a +tolerably uniform pace. Our review of that progress will show that here +and there in its course have been _leaps_, as radically new forces have +been brought under the dominion of man. We of the electric revolution +are sharply marked off from our great-grandfathers, who looked upon the +cell of Volta as a curious toy. They, in their turn, were profoundly +differenced from the men of the seventeenth century, who had not learned +that flame could outvie the horse as a carrier, and grind wheat better +than the mill urged by the breeze. And nothing short of an abyss +stretches between these men and their remote ancestors, who had not +found a way to warm their frosted fingers or lengthen with lamp or +candle the short, dark days of winter. + +Throughout the pages of this book there will be some recital of the +victories won by the fire-maker, the electrician, the photographer, and +many more in the peerage of experiment and research. Underlying the +sketch will appear the significant contrast betwixt accessions of minor +and of supreme dignity. The finding a new wood, such as that of the yew, +means better bows for the archer, stronger handles for the tool-maker; +the subjugation of a universal force such as fire, or electricity, +stands for the exaltation of power in every field of toil, for the +creation of a new earth for the worker, new heavens for the thinker. As +a corollary, we shall observe that an increasing width of gap marks off +the successive stages of human progress from each other, so that its +latest stride is much the longest and most decisive. And it will be +further evident that, while every new faculty is of age-long derivation +from older powers and ancient aptitudes, it nevertheless comes to the +birth in a moment, as it were, and puts a strain of probably fatal +severity on those contestants who miss the new gift by however little. +We shall, therefore, find that the principle of permutation, here merely +indicated, accounts in large measure for three cardinal facts in the +history of man: First, his leaps forward; second, the constant +accelerations in these leaps; and third, the gap in the record of the +tribes which, in the illimitable past, have succumbed as forces of a new +edge and sweep have become engaged in the fray.[6] + +The interlacements of the arts of fire and of electricity are intimate +and pervasive. While many of the uses of flame date back to the dawn of +human skill, many more have become of new and higher value within the +last hundred years. Fire to-day yields motive power with tenfold the +economy of a hundred years ago, and motive power thus derived is the +main source of modern electric currents. In metallurgy there has long +been an unwitting preparation for the advent of the electrician, and +here the services of fire within the nineteenth century have won +triumphs upon which the later successes of electricity largely proceed. +In producing alloys, and in the singular use of heat to effect its own +banishment, novel and radical developments have been recorded within the +past decade or two. These, also, make easier and bolder the +electrician's tasks. The opening chapters of this book will, therefore, +bestow a glance at the principal uses of fire as these have been +revealed and applied. This glance will make clear how fire and +electricity supplement each other with new and remarkable gains, while +in other fields, not less important, electricity is nothing else than a +supplanter of the very force which made possible its own discovery and +impressment. + +[Here follow chapters which outline the chief applications of flame and +of electricity.] + +Let us compare electricity with its precursor, fire, and we shall +understand the revolution by which fire is now in so many tasks +supplanted by the electric pulse which, the while, creates for itself a +thousand fields denied to flame. Copper is an excellent thermal +conductor, and yet it transmits heat almost infinitely more slowly than +it conveys electricity. One end of a thick copper rod ten feet long may +be safely held in the hand while the other end is heated to redness, +yet one millionth part of this same energy, if in the form of +electricity, would traverse the rod in one 100,000,000th part of a +second. Compare next electricity with light, often the companion of +heat. Light travels in straight lines only; electricity can go round a +corner every inch for miles, and, none the worse, yield a brilliant beam +at the end of its journey. Indirectly, therefore, electricity enables us +to conduct either heat or light as if both were flexible pencils of +rays, and subject to but the smallest tolls in their travel. + +We have remarked upon such methods as those of the electric welder which +summon intense heat without fire, and we have glanced at the electric +lamps which shine just because combustion is impossible through their +rigid exclusion of air. Then for a moment we paused to look at the +plating baths which have developed themselves into a commanding rivalry +with the blaze of the smelting furnace, with the flame which from time +immemorial has filled the ladle of the founder and moulder. Thus methods +that commenced in dismissing flame end boldly by dispossessing heat +itself. But, it may be said, this usurping electricity usually finds its +source, after all, in combustion under a steam-boiler. True, but mark +the harnessing of Niagara, of the Lachine Rapids near Montreal, of a +thousand streams elsewhere. In the near future motive power of Nature's +giving is to be wasted less and less, and perforce will more and more +exclude heat from the chain of transformations which issue in the +locomotive's flight, in the whirl of factory and mill. Thus in some +degree is allayed the fear, never well grounded, that when the coal +fields of the globe are spent civilization must collapse. As the +electrician hears this foreboding he recalls how much fuel is wasted in +converting heat into electricity. He looks beyond either turbine or +shaft turned by wind or tide, and, remembering that the metal dissolved +in his battery yields at his will its full content of energy, either as +heat or electricity, he asks, Why may not coal or forest tree, which are +but other kinds of fuel, be made to do the same? + +One of the earliest uses of light was a means of communicating +intelligence, and to this day the signal lamp and the red fire of the +mariner are as useful as of old. But how much wider is the field of +electricity as it creates the telegraph and the telephone! In the +telegraph we have all that a pencil of light could be were it as long as +an equatorial girdle and as flexible as a silken thread. In the +telephone for nearly two thousand miles the pulsations of the speaker's +voice are not only audible, but retain their characteristic tones. + +In the field of mechanics electricity is decidedly preferable to any +other agent. Heat may be transformed into motive power by a suitable +engine, but there its adaptability is at an end. An electric current +drives not only a motor, but every machine and tool attached to the +motor, the whole executing tasks of a delicacy and complication new to +industrial art. On an electric railroad an identical current propels the +train, directs it by telegraph, operates its signals, provides it with +light and heat, while it stands ready to give constant verbal +communication with any station on the line, if this be desired. + +In the home electricity has equal versatility, at once promoting +healthfulness, refinement and safety. Its tiny button expels the +hazardous match as it lights a lamp which sends forth no baleful fumes. +An electric fan brings fresh air into the house--in summer as a grateful +breeze. Simple telephones, quite effective for their few yards of wire, +give a better because a more flexible service than speaking-tubes. Few +invalids are too feeble to whisper at the light, portable ear of metal. +Sewing-machines and the more exigent apparatus of the kitchen and +laundry transfer their demands from flagging human muscles to the +tireless sinews of electric motors--which ask no wages when they stand +unemployed. Similar motors already enjoy favour in working the elevators +of tall dwellings in cities. If a householder is timid about burglars, +the electrician offers him a sleepless watchman in the guise of an +automatic alarm; if he has a dread of fire, let him dispose on his walls +an array of thermometers that at the very inception of a blaze will +strike a gong at headquarters. But these, after all, are matters of +minor importance in comparison with the foundations upon which may be +reared, not a new piece of mechanism, but a new science or a new art. + +In the recent swift subjugation of the territory open alike to the +chemist and the electrician, where each advances the quicker for the +other's company, we have fresh confirmation of an old truth--that the +boundary lines which mark off one field of science from another are +purely artificial, are set up only for temporary convenience. The +chemist has only to dig deep enough to find that the physicist and +himself occupy common ground. "Delve from the surface of your sphere to +its heart, and at once your radius joins every other." Even the briefest +glance at electro-chemistry should pause to acknowledge its profound +debt to the new theories as to the bonding of atoms to form molecules, +and of the continuity between solution and electrical dissociation. +However much these hypotheses may be modified as more light is shed on +the geometry and the journeyings of the molecule, they have for the time +being recommended themselves as finder-thoughts of golden value. These +speculations of the chemist carry him back perforce to the days of his +childhood. As he then joined together his black and white bricks he +found that he could build cubes of widely different patterns. It was in +propounding a theory of molecular architecture that Kekule gave an +impetus to a vast and growing branch of chemical industry--that of the +synthetic production of dyes and allied compounds. + +It was in pure research, in paths undirected to the market-place, that +such theories have been thought out. Let us consider electricity as an +aid to investigation conducted for its own sake. The chief physical +generalization of our time, and of all time, the persistence of force, +emerged to view only with the dawn of electric art. When it was observed +that electricity might become heat, light, chemical action, or +mechanical motion, that in turn any of these might produce electricity, +it was at once indicated that all these phases of energy might differ +from each other only as the movements in circles, volutes, and spirals +of ordinary mechanism. The suggestion was confirmed when electrical +measurers were refined to the utmost precision, and a single quantum of +energy was revealed a very Proteus in its disguises, yet beneath these +disguises nothing but constancy itself. + +"There is that scattereth, and yet increaseth; and there is that +withholdeth more than is meet, but it tendeth to poverty." Because the +geometers of old patiently explored the properties of the triangle, the +circle, and the ellipse, simply for pure love of truth, they laid the +corner-stones for the arts of the architect, the engineer, and the +navigator. In like manner it was the disinterested work of investigation +conducted by Ampere, Faraday, Henry and their compeers, in ascertaining +the laws of electricity which made possible the telegraph, the +telephone, the dynamo, and the electric furnace. The vital relations +between pure research and economic gain have at last worked themselves +clear. It is perfectly plain that a man who has it in him to discover +laws of matter and energy does incomparably more for his kind than if he +carried his talents to the mint for conversion into coin. The voyage of +a Columbus may not immediately bear as much fruit as the uncoverings of +a mine prospector, but in the long run a Columbus makes possible the +finding many mines which without him no prospector would ever see. +Therefore let the seed-corn of knowledge be planted rather than eaten. +But in choosing between one research and another it is impossible to +foretell which may prove the richer in its harvests; for instance, all +attempts thus far economically to oxidize carbon for the production of +electricity have failed, yet in observations that at first seemed +equally barren have lain the hints to which we owe the incandescent lamp +and the wireless telegraph. + +Perhaps the most promising field of electrical research is that of +discharges at high pressures; here the leading American investigators +are Professor John Trowbridge and Professor Elihu Thomson. Employing a +tension estimated at one and a half millions volts, Professor Trowbridge +has produced flashes of lightning six feet in length in atmospheric air; +in a tube exhausted to one-seventh of atmospheric pressure the flashes +extended themselves to forty feet. According to this inquirer, the +familiar rending of trees by lightning is due to the intense heat +developed in an instant by the electric spark; the sudden expansion of +air or steam in the cavities of the wood causes an explosion. The +experiments of Professor Thomson confront him with some of the seeming +contradictions which ever await the explorer of new scientific +territory. In the atmosphere an electrical discharge is facilitated when +a metallic terminal (as a lightning rod) is shaped as a point; under oil +a point is the form least favourable to discharge. In the same line of +paradox it is observed that oil steadily improves in its insulating +effect the higher the electrical pressure committed to its keeping; with +air as an insulator the contrary is the fact. These and a goodly array +of similar puzzles will, without doubt, be cleared up as students in the +twentieth century pass from the twilight of anomaly to the sunshine of +ascertained law. + +"Before there can be applied science there must be science to apply," +and it is by enabling the investigator to know nature under a fresh +aspect that electricity rises to its highest office. The laboratory +routine of ascertaining the conductivity, polarisability, and other +electrical properties of matter is dull and exacting work, but it opens +to the student new windows through which to peer at the architecture of +matter. That architecture, as it rises to his view, discloses one law of +structure after another; what in a first and clouded glance seemed +anomaly is now resolved and reconciled; order displays itself where +once anarchy alone appeared. When the investigator now needs a substance +of peculiar properties he knows where to find it, or has a hint for its +creation--a creation perhaps new in the history of the world. As he +thinks of the wealth of qualities possessed by his store of alloys, +salts, acids, alkalies, new uses for them are borne into his mind. Yet +more--a new orchestration of inquiry is possible by means of the +instruments created for him by the electrician, through the advances in +method which these instruments effect. With a second and more intimate +point of view arrives a new trigonometry of the particle, a trigonometry +inconceivable in pre-electric days. Hence a surround is in progress +which early in the twentieth century may go full circle, making atom and +molecule as obedient to the chemist as brick and stone are to the +builder now. + +The laboratory investigator and the commercial exploiter of his +discoveries have been by turns borrower and lender, to the great profit +of both. What Leyden jar could ever be constructed of the size and +revealing power of an Atlantic cable? And how many refinements of +measurement, of purification of metals, of precision in manufacture, +have been imposed by the colossal investments in deep-sea telegraphy +alone! When a current admitted to an ocean cable, such as that between +Brest and New York, can choose for its path either 3,540 miles of copper +wire or a quarter of an inch of gutta-percha, there is a dangerous +opportunity for escape into the sea, unless the current is of nicely +adjusted strength, and the insulator has been made and laid with the +best-informed skill, the most conscientious care. In the constant tests +required in laying the first cables Lord Kelvin (then Professor William +Thomson) felt the need for better designed and more sensitive +galvanometers or current measurers. His great skill both as a +mathematician and a mechanician created the existing instruments, which +seem beyond improvement. They serve not only in commerce and +manufacture, but in promoting the strictly scientific work of the +laboratory. Now that electricity purifies copper as fire cannot, the +mathematician is able to treat his problems of long-distance +transmission, of traction, of machine design, with an economy and +certainty impossible when his materials were not simply impure, but +impure in varying and indefinite degrees. The factory and the workshop +originally took their magneto-machines from the experimental laboratory; +they have returned them remodelled beyond recognition as dynamos and +motors of almost ideal effectiveness. + +A galvanometer actuated by a thermo-electric pile furnishes much the +most sensitive means of detecting changes of temperature; hence +electricity enables the physicist to study the phenomena of heat with +new ease and precision. It was thus that Professor Tyndall conducted +the classical researches set forth in his "Heat as a Mode of Motion," +ascertaining the singular power to absorb terrestrial heat which makes +the aqueous vapours of the atmosphere act as an indispensable blanket to +the earth. + +And how vastly has electricity, whether in the workshop or laboratory, +enlarged our conceptions of the forces that thrill space, of the +substances, seemingly so simple, that surround us--substances that +propound questions of structure and behaviour that silence the acutest +investigator. "You ask me," said a great physicist, "if I have a theory +of the _universe_? Why, I haven't even a theory of _magnetism_!" + +The conventional phrase "conducting a current" is now understood to be +mere figure of speech; it is thought that a wire does little else than +give direction to electric energy. Pulsations of high tension have been +proved to be mainly superficial in their journeys, so that they are best +conveyed (or convoyed) by conductors of tubular form. And what is it +that moves when we speak of conduction? It seems to be now the molecule +of atomic chemistry, and anon the same ether that undulates with light +or radiant heat. Indeed, the conquest of electricity means so much +because it impresses the molecule and the ether into service as its +vehicles of communication. Instead of the old-time masses of metal, or +bands of leather, which moved stiffly through ranges comparatively +short, there is to-day employed a medium which may traverse 186,400 +miles in a second, and with resistances most trivial in contrast with +those of mechanical friction. + +And what is friction in the last analysis but the production of motion +in undesired forms, the allowing valuable energy to do useless work? In +that amazing case of long distance transmission, common sunshine, a +solar beam arrives at the earth from the sun not one whit the weaker for +its excursion of 92,000,000 miles. It is highly probable that we are +surrounded by similar cases of the total absence of friction in the +phenomena of both physics and chemistry, and that art will come nearer +and nearer to nature in this immunity is assured when we see how many +steps in that direction have already been taken by the electrical +engineer. In a preceding page a brief account was given of the theory +that gases and vapours are in ceaseless motion. This motion suffers no +abatement from friction, and hence we may infer that the molecules +concerned are perfectly elastic. The opinion is gaining ground among +physicists that all the properties of matter, transparency, chemical +combinability, and the rest, are due to immanent motion in particular +orbits, with diverse velocities. If this be established, then these +motions also suffer no friction, and go on without resistance forever. + +As the investigators in the vanguard of science discuss the constitution +of matter, and weave hypotheses more or less fruitful as to the +interplay of its forces, there is a growing faith that the day is at +hand when the tie between electricity and gravitation will be +unveiled--when the reason why matter has weight will cease to puzzle the +thinker. Who can tell what relief of man's estate may be bound up with +the ability to transform any phase of energy into any other without the +circuitous methods and serious losses of to-day! In the sphere of +economic progress one of the supreme advances was due to the invention +of money, the providing a medium for which any salable thing may be +exchanged, with which any purchasable thing may be bought. As soon as a +shell, or a hide, or a bit of metal was recognized as having universal +convertibility, all the delays and discounts of barter were at an end. +In the world of physics and chemistry the corresponding medium is +electricity; let it be produced as readily as it produces other modes of +motion, and human art will take a stride forward such as when Volta +disposed his zinc and silver discs together, or when Faraday set a +magnet moving around a copper wire. + +For all that the electric current is not as yet produced as economically +as it should be, we do wrong if we regard it as an infant force. However +much new knowledge may do with electricity in the laboratory, in the +factory, or in the exchange, some of its best work is already done. It +is not likely ever to perform a greater feat than placing all mankind +within ear-shot of each other. Were electricity unmastered there could +be no democratic government of the United States. To-day the drama of +national affairs is more directly in view of every American citizen +than, a century ago, the public business of Delaware could be to the men +of that little State. And when on the broader stage of international +politics misunderstandings arise, let us note how the telegraph has +modified the hard-and-fast rules of old-time diplomacy. To-day, through +the columns of the press, the facts in controversy are instantly +published throughout the world, and thus so speedily give rise to +authoritative comment that a severe strain is put upon negotiators whose +tradition it is to be both secret and slow. + +Railroads, with all they mean for civilization, could not have extended +themselves without the telegraph to control them. And railroads and +telegraphs are the sinews and nerves of national life, the prime +agencies in welding the diverse and widely separated States and +Territories of the Union. A Boston merchant builds a cotton-mill in +Georgia; a New York capitalist opens a copper-mine in Arizona. The +telegraph which informs them day by day how their investments prosper +tells idle men where they can find work, where work can seek idle men. +Chicago is laid in ashes, Charleston topples in earthquake, Johnstown is +whelmed in flood, and instantly a continent springs to their relief. And +what benefits issue in the strictly commercial uses of the telegraph! +At its click both locomotive and steamship speed to the relief of famine +in any quarter of the globe. In times of plenty or of dearth the markets +of the globe are merged and are brought to every man's door. Not less +striking is the neighbourhood guild of science, born, too, of the +telegraph. The day after Roentgen announced his X rays, physicists on +every continent were repeating his experiments--were applying his +discovery to the healing of the wounded and diseased. Let an anti-toxin +for diphtheria, consumption, or yellow fever be proposed, and a hundred +investigators the world over bend their skill to confirm or disprove, as +if the suggester dwelt next door. + +On a stage less dramatic, or rather not dramatic at all, electricity +works equal good. Its motor freeing us from dependence on the horse is +spreading our towns and cities into their adjoining country. Field and +garden compete with airless streets. The sunny cottage is in active +rivalry with the odious tenement-house. It is found that transportation +within the gates of a metropolis has an importance second only to the +means of transit which links one city with another. The engineer is at +last filling the gap which too long existed between the traction of +horses and that of steam. In point of speed, cleanliness, and comfort +such an electric subway as that of South London leaves nothing to be +desired. Throughout America electric roads, at first suburban, are now +fast joining town to town and city to city, while, as auxiliaries to +steam railroads, they place sparsely settled communities in the arterial +current of the world, and build up a ready market for the dairyman and +the fruit-grower. In its saving of what Mr. Oscar T. Crosby has called +"man-hours" the third-rail system is beginning to oust steam as a motive +power from trunk-lines. Already shrewd railroad managers are granting +partnerships to the electricians who might otherwise encroach upon their +dividends. A service at first restricted to passengers has now extended +itself to the carriage of letters and parcels, and begins to reach out +for common freight. We may soon see the farmer's cry for good roads +satisfied by good electric lines that will take his crops to market much +more cheaply and quickly than horses and macadam ever did. In cities, +electromobile cabs and vans steadily increase in numbers, furthering the +quiet and cleanliness introduced by the trolley car. + +A word has been said about the blessings which electricity promises to +country folk, yet greater are the boons it stands ready to bestow in the +hives of population. Until a few decades ago the water-supply of cities +was a matter not of municipal but of individual enterprise; water was +drawn in large part from wells here and there, from lines of piping laid +in favoured localities, and always insufficient. Many an epidemic of +typhoid fever was due to the contamination of a spring by a cesspool a +few yards away. To-day a supply such as that of New York is abundant +and cheap because it enters every house. Let a centralized electrical +service enjoy a like privilege, and it will offer a current which is +heat, light, chemical energy, or motive power, and all at a wage lower +than that of any other servant. Unwittingly, then, the electrical +engineer is a political reformer of high degree, for he puts a new +premium upon ability and justice at the City Hall. His sole condition is +that electricity shall be under control at once competent and honest. +Let us hope that his plea, joined to others as weighty, may quicken the +spirit of civic righteousness so that some of the richest fruits ever +borne in the garden of science and art may not be proffered in vain. +Flame, the old-time servant, is individual; electricity, its successor +and heir, is collective. Flame sits upon the hearth and draws a family +together; electricity, welling from a public source, may bind into a +unit all the families of a vast city, because it makes the benefit of +each the interest of all. + +But not every promise brought forward in the name of the electrician has +his assent or sanction. So much has been done by electricity, and so +much more is plainly feasible, that a reflection of its triumphs has +gilded many a baseless dream. One of these is that the cheap electric +motor, by supply power at home, will break up the factory system, and +bring back the domestic manufacturing of old days. But if this power +cost nothing at all the gift would leave the factory unassailed; for we +must remember that power is being steadily reduced in cost from year to +year, so that in many industries it has but a minor place among the +expenses of production. The strength and profit of the factory system +lie in its assembling a wide variety of machines, the first delivering +its product to the second for another step toward completion, and so on +until a finished article is sent to the ware-room. It is this minute +subdivision of labour, together with the saving and efficiency that +inure to a business conducted on an immense scale under a single +manager, that bids us believe that the factory has come to stay. To be +sure, a weaver, a potter, or a lens-grinder of peculiar skill may thrive +at his loom or wheel at home; but such a man is far from typical in +modern manufacture. Besides, it is very questionable whether the +lamentations over the home industries of the past do not ignore evil +concomitants such as still linger in the home industries of the +present--those of the sweater's den, for example. + +This rapid survey of what electricity has done and may yet do--futile +expectation dismissed--has shown it the creator of a thousand material +resources, the perfector of that communication of things, of power, of +thought, which in every prior stage of advancement has marked the +successive lifts of humanity. It was much when the savage loaded a pack +upon a horse or an ox instead of upon his own back; it was yet more when +he could make a beacon-flare give news or warning to a whole +country-side, instead of being limited to the messages which might be +read in his waving hands. All that the modern engineer was able to do +with steam for locomotion is raised to a higher plane by the advent of +his new power, while the long-distance transmission of electrical energy +is contracting the dimensions of the planet to a scale upon which its +cataracts in the wilderness drive the spindles and looms of the factory +town, or illuminate the thoroughfares of cities. Beyond and above all +such services as these, electricity is the corner-stone of physical +generalization, a revealer of truths impenetrable by any other ray. + +The subjugation of fire has done much in giving man a new independence +of nature, a mighty armoury against evil. In curtailing the most arduous +and brutalizing forms of toil, electricity, that subtler kind of fire, +carries this emancipation a long step further, and, meanwhile, bestows +upon the poor many a luxury which but lately was the exclusive +possession of the rich. In more closely binding up the good of the bee +with the welfare of the hive, it is an educator and confirmer of every +social bond. In so far as it proffers new help in the war on pain and +disease it strengthens the confidence of man in an Order of Right and +Happiness which for so many dreary ages has been a matter rather of hope +than of vision. Are we not, then, justified in holding electricity to be +a multiplier of faculty and insight, a means of dignifying mind and +soul, unexampled since man first kindled fire and rejoiced? + +We have traced how dexterity rose to fire-making, how fire-making led to +the subjugation of electricity. Much of the most telling work of fire +can be better done by its great successor, while electricity performs +many tasks possible only to itself. Unwitting truth there was in the +simple fable of the captive who let down a spider's film, that drew up a +thread, which in turn brought up a rope--and freedom. It was in 1800 on +the threshold of the nineteenth century, that Volta devised the first +electric battery. In a hundred years the force then liberated has +vitally interwoven itself with every art and science, bearing fruit not +to be imagined even by men of the stature of Watt, Lavoisier, or +Humboldt. Compare this rapid march of conquest with the slow adaptation, +through age after age, of fire to cooking, smelting, tempering. Yet it +was partly, perhaps mainly, because the use of fire had drawn out man's +intelligence and cultivated his skill that he was ready in the fulness +of time so quickly to seize upon electricity and subdue it. + +Electricity is as legitimately the offspring of fire as fire of the +simple knack in which one savage in ten thousand was richer than his +fellows. The principle of permutation, suggested in both victories, +interprets not only how vast empire is won by a new weapon of prime +dignity; it explains why such empires are brought under rule with +ever-accelerated pace. Every talent only pioneers the way for the +richer talents which are born from it. + + +FOOTNOTES: + +[5] Permutations are the various ways in which two or more different +things may be arranged in a row, all the things appearing in each row. +Permutations are readily illustrated with squares or cubes of different +colours, with numbers, or letters. + +Permutations of two elements, 1 and 2, are (1 x 2) two; 1, 2; 2, 1; or +_a_, _b_; _b_, _a_. Of three elements the permutations are (1 x 2 x 3) +six; 1, 2, 3; 1, 3, 2; 2, 1, 3; 2, 3, 1; 3, 1, 2; 3, 2, 1; or _a_, _b_, +_c_; _a_, _c_, _b_; _b_, _a_, _c_; _b_, _c_, _a_; _c_, _a_, _b_; _c_, +_b_, _a_. Of four elements the permutations are (1 x 2 x 3 x 4) +twenty-four; of five elements, one hundred and twenty, and so on. A new +element or permutator multiplies by an increasing figure all the +permutations it finds. + +[6] Some years ago I sent an outline of this argument to Herbert +Spencer, who replied: "I recognize a novelty and value in your inference +that the law implies an increasing width of gap between lower and higher +types as evolution advances." + + + + +COUNT RUMFORD IDENTIFIES HEAT WITH MOTION. + + [Benjamin Thompson, who received the title of Count Rumford from + the Elector of Bavaria, was born in Woburn, Massachusetts, in 1753. + When thirty-one years of age he settled in Munich, where he devoted + his remarkable abilities to the public service. Twelve years + afterward he removed to England; in 1800 he founded the Royal + Institution of London, since famous as the theatre of the labours + of Davy, Faraday, Tyndall, and Dewar. He bequeathed to Harvard + University a fund to endow a professorship of the application of + science to the art of living: he instituted a prize to be awarded + by the American Academy of Sciences for the most important + discoveries and improvements relating to heat and light. In 1804 he + married the widow of the illustrious chemist Lavoisier: he died in + 1814. Count Rumford on January 25, 1798, read a paper before the + Royal Society entitled "An Enquiry Concerning the Source of Heat + Which Is Excited by Friction." The experiments therein detailed + proved that heat is identical with motion, as against the notion + that heat is matter. He thus laid the corner-stone of the modern + theory that heat light, electricity, magnetism, chemical action, + and all other forms of energy are in essence motion, are + convertible into one another, and as motion are indestructible. The + following abstract of Count Rumford's paper is taken from "Heat as + a Mode of Motion," by Professor John Tyndall, published by D. + Appleton & Co., New York. This work and "The Correlation and + Conservation of Forces," edited by Dr. E. L. Youmans, published by + the same house, will serve as a capital introduction to the modern + theory that energy is motion which, however varied in its forms, is + changeless in its quantity.] + + +Being engaged in superintending the boring of cannon in the workshops of +the military arsenal at Munich, Count Rumford was struck with the very +considerable degree of heat which a brass gun acquires, in a short time, +in being bored, and with the still more intense heat (much greater than +that of boiling water) of the metallic chips separated from it by the +borer, he proposed to himself the following questions: + +"Whence comes the heat actually produced in the mechanical operations +above mentioned? + +"Is it furnished by the metallic chips which are separated from the +metal?" + +If this were the case, then the _capacity for heat_ of the parts of the +metal so reduced to chips ought not only to be changed, but the change +undergone by them should be sufficiently great to account for _all_ the +heat produced. No such change, however, had taken place, for the chips +were found to have the same capacity as slices of the same metal cut by +a fine saw, where heating was avoided. Hence, it is evident, that the +heat produced could not possibly have been furnished at the expense of +the latent heat of the metallic chips. Rumford describes these +experiments at length, and they are conclusive. + +He then designed a cylinder for the express purpose of generating heat +by friction, by having a blunt borer forced against its solid bottom, +while the cylinder was turned around its axis by the force of horses. To +measure the heat developed, a small round hole was bored in the +cylinder for the purpose of introducing a small mercurial thermometer. +The weight of the cylinder was 113.13 pounds avoirdupois. + +The borer was a flat piece of hardened steel, 0.63 of an inch thick, +four inches long, and nearly as wide as the cavity of the bore of the +cylinder, namely, three and one-half inches. The area of the surface by +which its end was in contact with the bottom of the bore was nearly two +and one-half inches. At the beginning of the experiment the temperature +of the air in the shade, and also that of the cylinder, was 60 deg. Fahr. At +the end of thirty minutes, and after the cylinder had made 960 +revolutions round its axis, the temperature was found to be 130 deg.. + +Having taken away the borer, he now removed the metallic dust, or rather +scaly matter, which had been detached from the bottom of the cylinder by +the blunt steel borer, and found its weight to be 837 grains troy. "Is +it possible," he exclaims, "that the very considerable quantity of heat +produced in this experiment--a quantity which actually raised the +temperature of above 113 pounds of gun-metal at least 70 deg. of +Fahrenheit's thermometer--could have been furnished by so inconsiderable +a quantity of metallic dust and this merely in consequence of a _change_ +in its capacity of heat?" + +"But without insisting on the improbability of this supposition, we have +only to recollect that from the results of actual and decisive +experiments, made for the express purpose of ascertaining that fact, +the capacity for heat for the metal of which great guns are cast is _not +sensibly changed_ by being reduced to the form of metallic chips, and +there does not seem to be any reason to think that it can be much +changed, if it be changed at all, in being reduced to much smaller +pieces by a borer which is less sharp." + +He next surrounded his cylinder by an oblong deal-box, in such a manner +that the cylinder could turn water-tight in the centre of the box, while +the borer was pressed against the bottom of the cylinder. The box was +filled with water until the entire cylinder was covered, and then the +apparatus was set in action. The temperature of the water on commencing +was 60 deg.. + +"The result of this beautiful experiment," writes Rumford, "was very +striking, and the pleasure it afforded me amply repaid me for all the +trouble I had had in contriving and arranging the complicated machinery +used in making it. The cylinder had been in motion but a short time, +when I perceived, by putting my hand into the water, and touching the +outside of the cylinder, that heat was generated. + +"At the end of one hour the fluid, which weighed 18.77 pounds, or two +and one-half gallons, had its temperature raised forty-seven degrees, +being now 107 deg.. + +"In thirty minutes more, or one hour and thirty minutes after the +machinery had been set in motion, the heat of the water was 142 deg.. + +"At the end of two hours from the beginning, the temperature was 178 deg.. + +"At two hours and twenty minutes it was 200 deg., and at two hours and +thirty minutes it _actually boiled_!" + +"It would be difficult to describe the surprise and astonishment +expressed in the countenances of the bystanders on seeing so large a +quantity of water heated, and actually made to boil, without any fire. +Though, there was nothing that could be considered very surprising in +this matter, yet I acknowledge fairly that it afforded me a degree of +childish pleasure which, were I ambitious of the reputation of a grave +philosopher, I ought most certainly rather to hide than to discover." + +He then carefully estimates the quantity of heat possessed by each +portion of his apparatus at the conclusion of the experiment, and, +adding all together, finds a total sufficient to raise 26.58 pounds of +ice-cold water to its boiling point, or through 180 deg. Fahrenheit. By +careful calculation, he finds this heat equal to that given out by the +combustion of 2,303.8 grains (equal to four and eight-tenths ounces +troy) of wax. + +He then determines the "_celerity_" with which the heat was generated, +summing up thus: "From the results of these computations, it appears +that the quantity of heat produced equably, or in a continuous stream, +if I may use the expression, by the friction of the blunt steel borer +against the bottom of the hollow metallic cylinder, was _greater_ than +that produced in the combustion of nine _wax-candles_, each +three-quarters of an inch in diameter, all burning together with clear +bright flames. + +"One horse would have been equal to the work performed, though two were +actually employed. Heat may thus be produced merely by the strength of a +horse, and, in a case of necessity, this heat might be used in cooking +victuals. But no circumstances could be imagined in which this method of +procuring heat would be advantageous, for more heat might be obtained by +using the fodder necessary for the support of a horse as fuel." + +[This is an extremely significant passage, intimating as it does, that +Rumford saw clearly that the force of animals was derived from the food; +_no creation of force_ taking place in the animal body.] + +"By meditating on the results of all these experiments, we are naturally +brought to that great question which has so often been the subject of +speculation among philosophers, namely, What is heat--is there any such +thing as an _igneous fluid_? Is there anything that, with propriety, can +be called caloric? + +"We have seen that a very considerable quantity of heat may be excited +by the friction of two metallic surfaces, and given off in a constant +stream or flux _in all directions_, without interruption or +intermission, and without any signs of _diminution_ or _exhaustion_. In +reasoning on this subject we must not forget _that most remarkable +circumstance_, that the source of the heat generated by friction in +these experiments appeared evidently to be _inexhaustible_. [The italics +are Rumford's.] It is hardly necessary to add, that anything which any +_insulated_ body or system of bodies can continue to furnish _without +limitation_ cannot possibly be a _material substance_; and it appears to +me to be extremely difficult, if not quite impossible, to form any +distinct idea of anything capable of being excited and communicated in +those experiments, except it be MOTION." + +When the history of the dynamical theory of heat is written, the man +who, in opposition to the scientific belief of his time, could +experiment and reason upon experiment, as Rumford did in the +investigation here referred to, cannot be lightly passed over. Hardly +anything more powerful against the materiality of heat has been since +adduced, hardly anything more conclusive in the way of establishing that +heat is, what Rumford considered it to be, _Motion_. + + + + +VICTORY OF THE "ROCKET" LOCOMOTIVE. + + [Part of Chapter XII. Part II, of "The Life of George Stephenson + and of His Son, Robert Stephenson," by Samuel Smiles New York, + Harper & Brothers, 1868.] + + +The works of the Liverpool and Manchester Railway were now approaching +completion. But, strange to say, the directors had not yet decided as to +the tractive power to be employed in working the line when open for +traffic. The differences of opinion among them were so great as +apparently to be irreconcilable. It was necessary, however, that they +should, come to some decision without further loss of time, and many +board meetings were accordingly held to discuss the subject. The +old-fashioned and well-tried system of horse-haulage was not without its +advocates; but, looking at the large amount of traffic which there was +to be conveyed, and at the probable delay in the transit from station to +station if this method were adopted, the directors, after a visit made +by them to the Northumberland and Durham railways in 1828, came to the +conclusion that the employment of horse-power was inadmissible. + +Fixed engines had many advocates; the locomotive very few: it stood as +yet almost in a minority of one--George Stephenson.... + +In the meantime the discussion proceeded as to the kind of power to be +permanently employed for the working of the railway. The directors were +inundated with schemes of all sorts for facilitating locomotion. The +projectors of England, France, and America seemed to be let loose upon +them. There were plans for working the waggons along the line by +water-power. Some proposed hydrogen, and others carbonic acid gas. +Atmospheric pressure had its eager advocates. And various kinds of fixed +and locomotive steam-power were suggested. Thomas Gray urged his plan of +a greased road with cog-rails; and Messrs. Vignolles and Ericsson +recommended the adoption of a central friction-rail, against which two +horizontal rollers under the locomotive, pressing upon the sides of this +rail, were to afford the means of ascending the inclined planes.... + +The two best practical engineers of the day concurred in reporting +substantially in favour of the employment of fixed engines. Not a single +professional man of eminence could be found to coincide with the +engineer of the railway in his preference for locomotive over fixed +engine power. He had scarcely a supporter, and the locomotive system +seemed on the eve of being abandoned. Still he did not despair. With the +profession against him, and public opinion against him--for the most +frightful stories went abroad respecting the dangers, the unsightliness, +and the nuisance which the locomotive would create--Stephenson held to +his purpose. Even in this, apparently the darkest hour of the +locomotive, he did not hesitate to declare that locomotive railroads +would, before many years had passed, be "the great highways of the +world." + +He urged his views upon the directors in all ways, in season, and, as +some of them thought, out of season. He pointed out the greater +convenience of locomotive power for the purposes of a public highway, +likening it to a series of short unconnected chains, any one of which +could be removed and another substituted without interruption to the +traffic; whereas the fixed-engine system might be regarded in the light +of a continuous chain extending between the two termini, the failure of +any link of which would derange the whole. But the fixed engine party +was very strong at the board, and, led by Mr. Cropper, they urged the +propriety of forthwith adopting the report of Messrs. Walker and +Rastrick. Mr. Sandars and Mr. William Rathbone, on the other hand, +desired that a fair trial should be given to the locomotive; and they +with reason objected to the expenditure of the large capital necessary +to construct the proposed engine-houses, with their fixed engines, +ropes, and machinery, until they had tested the powers of the locomotive +as recommended by their own engineer. George Stephenson continued to +urge upon them that the locomotive was yet capable of great +improvements, if proper inducements were held out to inventors and +machinists to make them; and he pledged himself that, if time were +given him, he would construct an engine that should satisfy their +requirements, and prove itself capable of working heavy loads along the +railway with speed, regularity, and safety. At length, influenced by his +persistent earnestness not less than by his arguments, the directors, at +the suggestion of Mr. Harrison, determined to offer a prize of L500 for +the best locomotive engine, which, on a certain day, should be produced +on the railway, and perform certain specified conditions in the most +satisfactory manner.[7] + +The requirements of the directors as to speed were not excessive. All +that they asked for was that ten miles an hour should be maintained. +Perhaps they had in mind the animadversions of the _Quarterly Review_ on +the absurdity of travelling at a greater velocity, and also the remarks +published by Mr. Nicholas Wood, whom they selected to be one of the +judges of the competition, in conjunction, with Mr. Rastrick, of +Stourbridge, and Mr. Kennedy, of Manchester. + +It was now felt that the fate of railways in a great measure depended +upon the issue of this appeal to the mechanical genius of England. When +the advertisement of the prize for the best locomotive was published, +scientific men began more particularly to direct their attention to the +new power which was thus struggling into existence. In the meantime +public opinion on the subject of railway working remained suspended, and +the progress of the undertaking was watched with intense interest. + +During the progress of this important controversy with reference to the +kind of power to be employed in working the railway, George Stephenson +was in constant communication with his son Robert, who made frequent +visits to Liverpool for the purpose of assisting his father in the +preparation of his reports to the board on the subject. Mr. Swanwick +remembers the vivid interest of the evening discussions which then took +place between father and son as to the best mode of increasing the +powers and perfecting the mechanism of the locomotive. He wondered at +their quick perception and rapid judgment on each other's suggestions; +at the mechanical difficulties which they anticipated and provided for +in the practical arrangement of the machine; and he speaks of these +evenings as most interesting displays of two actively ingenious and able +minds stimulating each other to feats of mechanical invention, by which +it was ordained that the locomotive engine should become what it now is. +These discussions became more frequent, and still more interesting, +after the public prize had been offered for the best locomotive by the +directors of the railway, and the working plans of the engine which they +proposed to construct had to be settled. + +One of the most important considerations in the new engine was the +arrangement of the boiler, and the extension of its heating surface to +enable steam enough to be raised rapidly and continuously for the +purpose of maintaining high rates of speed--the effect of high pressure +engines being ascertained to depend mainly upon the quantity of steam +which the boiler can generate, and upon its degree of elasticity when +produced. The quantity of steam so generated, it will be obvious, must +chiefly depend upon the quantity of fuel consumed in the furnace, and, +by necessary consequence, upon the high rate of temperature maintained +there. + +It will be remembered that in Stephenson's first Killingworth engines he +invited and applied the ingenious method of stimulating combustion in +the furnace by throwing the waste steam into the chimney after +performing its office in the cylinders, thereby accelerating the ascent +of the current of air, greatly increasing the draught, and consequently +the temperature of the fire. This plan was adopted by him, as we have +seen, as early as 1815, and it was so successful that he himself +attributed to it the greater economy of the locomotive as compared with +horse-power. Hence the continuance of its use upon the Killingworth +Railway. + +Though the adoption of the steam blast greatly quickened combustion and +contributed to the rapid production of high-pressure steam, the limited +amount of heating surface presented to the fire was still felt to be an +obstacle to the complete success of the locomotive engine. Mr. +Stephenson endeavoured to overcome this by lengthening the boilers and +increasing the surface presented by the flue-tubes. The "Lancashire +Witch," which he built for the Bolton and Leigh Railway, and used in +forming the Liverpool and Manchester Railway embankments, was +constructed with a double tube, each of which contained a fire, and +passed longitudinally through the boiler. But this arrangement +necessarily led to a considerable increase in the weight of those +engines, which amounted to about twelve tons each; and as six tons was +the limit allowed for engines admitted to the Liverpool competition, it +was clear that the time was come when the Killingworth engine must +undergo a farther important modification. + +For many years previous to this period, ingenious mechanics had been +engaged in attempting to solve the problem of the best and most +economical boiler for the production of high-pressure steam. + +The use of tubes in boilers for increasing the heating surface had long +been known. As early as 1780, Matthew Boulton employed copper tubes +longitudinally in the boiler of the Wheal Busy engine in Cornwall--the +fire passing _through_ the tubes--and it was found that the production +of steam was thereby considerably increased. The use of tubular boilers +afterwards became common in Cornwall. In 1803, Woolf, the Cornish +engineer, patented a boiler with tubes, with the same object of +increasing the heating surface. The water was _inside_ the tubes, and +the fire of the boiler outside. Similar expedients were proposed by +other inventors. In 1815 Trevithick invented his light high-pressure +boiler for portable purposes, in which, to "expose a large surface to +the fire," he constructed the boiler of a number of small perpendicular +tubes "opening into a common reservoir at the top." In 1823 W. H. James +contrived a boiler composed of a series of annular wrought-iron tubes, +placed side by side and bolted together, so as to form by their union a +long cylindrical boiler, in the centre of which, at the end, the +fireplace was situated. The fire played round the tubes, which contained +the water. In 1826 James Neville took out a patent for a boiler with +vertical tubes surrounded by the water, through which the heated air of +the furnace passed, explaining also in his specification that the tubes +might be horizontal or inclined, according to circumstances. Mr. +Goldsworthy, the persevering adaptor of steam-carriages to travelling on +common roads, applied the tubular principle in the boiler of his engine, +in which the steam was generated _within_ the tubes; while the boiler +invented by Messrs. Summer and Ogle for their turnpike-road +steam-carriage consisted of a series of tubes placed vertically over the +furnace, through which the heated air passed before reaching the +chimney. + +About the same time George Stephenson was trying the effect of +introducing small tubes in the boilers of his locomotives, with the +object of increasing their evaporative power. Thus, in 1829, he sent to +France two engines constructed at the Newcastle works for the Lyons and +St. Etienne Railway, in the boilers of which tubes were placed +containing water. The heating surface was thus considerably increased; +but the expedient was not successful, for the tubes, becoming furred +with deposit, shortly burned out and were removed. It was then that M. +Seguin, the engineer of the railway, pursuing the same idea, is said to +have adopted his plan of employing horizontal tubes through which the +heated air passed in streamlets, and for which he took out a French +patent. + +In the meantime Mr. Henry Booth, secretary to the Liverpool and +Manchester Railway, whose attention had been directed to the subject on +the prize being offered for the best locomotive to work that line, +proposed the same method, which, unknown to him, Matthew Boulton had +employed but not patented, in 1780, and James Neville had patented, but +not employed, in 1826; and it was carried into effect by Robert +Stephenson in the construction of the "Rocket," which won the prize at +Rainhill in October, 1829. The following is Mr. Booth's account in a +letter to the author: + +"I was in almost daily communication with Mr. Stephenson at the time, +and I was not aware that he had any intention of competing for the prize +till I communicated to him my scheme of a multitubular boiler. This new +plan of boiler comprised the introduction of numerous small tubes, two +or three inches in diameter, and less than one-eighth of an inch thick, +through which to carry the fire instead of a single tube or flue +eighteen inches in diameter, and about half an inch thick, by which +plan we not only obtain a very much larger heating surface, but the +heating surface is much more effective, as there intervenes between the +fire and the water only a thin sheet of copper or brass, not an eighth +of an inch thick, instead of a plate of iron of four times the +substance, as well as an inferior conductor of heat. + +"When the conditions of trial were published, I communicated my +multitubular plan to Mr. Stephenson, and proposed to him that we should +jointly construct an engine and compete for the prize. Mr. Stephenson +approved the plan, and agreed to my proposal. He settled the mode in +which the fire-box and tubes were to be mutually arranged and connected, +and the engine was constructed at the works of Messrs. Robert Stephenson +& Co., Newcastle-on-Tyne. + +"I am ignorant of M. Seguin's proceedings in France, but I claim to be +the inventor in England, and feel warranted in stating, without +reservation, that until I named my plan to Mr. Stephenson, with a view +to compete for the prize at Rainhill, it had not been tried, and was not +known in this country." + +From the well-known high character of Mr. Booth, we believe his +statement to be made in perfect good faith, and that he was as much in +ignorance of the plan patented by Neville as he was of that of Seguin. +As we have seen, from the many plans of tubular boilers invented during +the preceding thirty years, the idea was not by any means new; and we +believe Mr. Booth to be entitled to the merit of inventing the method by +which the multitubular principle was so effectually applied in the +construction of the famous "Rocket" engine. + +The principal circumstances connected with the construction of the +"Rocket," as described by Robert Stephenson to the author, may be +briefly stated. The tubular principle was adopted in a more complete +manner than had yet been attempted. Twenty-five copper tubes, each three +inches in diameter, extended from one end of the boiler to the other, +the heated air passing through them on its way to the chimney; and the +tubes being surrounded by the water of the boiler, it will be obvious +that a large extension of the heating surface was thus effectually +secured. The principal difficulty was in fitting the copper tubes in the +boiler ends so as to prevent leakage. They were manufactured by a +Newcastle coppersmith, and soldered to brass screws which were screwed +into the boiler ends, standing out in great knobs. When the tubes were +thus fitted, and the boiler was filled with water, hydraulic pressure +was applied; but the water squirted out at every joint, and the factory +floor was soon flooded. Robert went home in despair; and in the first +moment of grief he wrote to his father that the whole thing was a +failure. By return of post came a letter from his father, telling him +that despair was not to be thought of--that he must "try again;" and he +suggested a mode of overcoming the difficulty, which his son had +already anticipated and proceeded to adopt. It was, to bore clean holes +in the boiler ends, fit in the smooth copper tubes as tightly as +possible, solder up, and then raise the steam. This plan succeeded +perfectly, the expansion of the copper tubes completely filling up all +interstices, and producing a perfectly water-tight boiler, capable of +withstanding extreme external pressure. + +The mode of employing the steam-blast for the purpose of increasing the +draught in the chimney was also the subject of numerous experiments. +When the engine was first tried, it was thought that the blast in the +chimney was not sufficiently strong for the purpose of keeping up the +intensity of fire in the furnace, so as to produce high-pressure steam +with the required velocity. The expedient was therefore adopted of +hammering the copper tubes at the point at which they entered the +chimney, whereby the blast was considerably sharpened; and on a farther +trial it was found that the draught was increased to such an extent as +to enable abundance of steam to be raised. The rationale of the blast +may be simply explained by referring to the effect of contracting the +pipe of a water-hose, by which the force of the jet of water is +proportionately increased. Widen the nozzle of the pipe, and the jet is +in like manner diminished. So it is with the steam-blast in the chimney +of the locomotive. + +Doubts were, however, expressed whether the greater draught obtained by +the contraction of the blast-pipe was not counterbalanced in some degree +by the negative pressure upon the piston. Hence a series of experiments +was made with pipes of different diameters, and their efficiency was +tested by the amount of vacuum that was produced in the smoke-box. The +degree of rarefaction was determined by a glass tube fixed to the bottom +of the smoke-box and descending into a bucket of water, the tube being +open at both ends. As the rarefaction took place, the water would, of +course, rise in the tube, and the height to which it rose above the +surface of the water in the bucket was made the measure of the amount of +rarefaction. These experiments proved that a considerable increase of +draught was obtained by the contraction of the orifice; accordingly, the +two blast-pipes opening from the cylinders into either side of the +"Rocket" chimney, and turned up within it, were contracted slightly +below the area of the steam-ports, and before the engine left the +factory, the water rose in the glass tube three inches above the water +in the bucket. + +The other arrangements of the "Rocket" were briefly these: the boiler +was cylindrical, with flat ends, six feet in length, and three feet four +inches in diameter. The upper half of the boiler was used as a reservoir +for the steam, the lower half being filled with water. Through the lower +part the copper tubes extended, being open to the fire-box at one end, +and to the chimney at the other. The fire-box, or furnace, two feet wide +and three feet high, was attached immediately behind the boiler, and was +also surrounded with water. The cylinders of the engine were placed on +each side of the boiler, in an oblique position, one end being nearly +level with the top of the boiler at its after end, and the other +pointing toward the centre of the foremost or driving pair of wheels, +with which the connection was directly made from the piston-rod to a pin +on the outside of the wheel. The engine, together with its load of +water, weighed only four tons and a quarter; and it was supported on +four wheels, not coupled. The tender was four-wheeled, and similar in +shape to a waggon--the foremost part holding the fuel, and the hind part +a water cask. + +When the "Rocket" was finished it was placed upon the Killingworth +Railway for the purpose of experiment. The new boiler arrangement was +found perfectly successful. The steam was raised rapidly and +continuously, and in a quantity which then appeared marvellous. The same +evening Robert despatched a letter to his father at Liverpool, informing +him, to his great joy, that the "Rocket" was "all right," and would be +in complete working trim by the day of trial. The engine was shortly +after sent by waggon to Carlisle, and thence shipped for Liverpool. + +The time so much longed for by George Stephenson had now arrived, when +the merits of the passenger locomotive were about to be put to the +test. He had fought the battle for it until now almost single-handed. +Engrossed by his daily labours and anxieties, and harassed by +difficulties and discouragements which would have crushed the spirit of +a less resolute man, he had held firmly to his purpose through good and +through evil report. The hostility which he experienced from some of the +directors opposed to the adoption of the locomotive was the circumstance +that caused him the greatest grief of all; for where he had looked for +encouragement, he found only carping and opposition. But his pluck never +failed him; and now the "Rocket" was upon the ground to prove, to use +his own words, "whether he was a man of his word or not." + +On the day appointed for the great competition of locomotives at +Rainhill the following engines were entered for the prize: + +1. Messrs. Braithwaite and Ericsson's "Novelty." + +2. Mr. Timothy Hackworth's "Sanspareil." + +3. Messrs. R. Stephenson & Co.'s "Rocket." + +4. Mr. Burstall's "Perseverance." + +The ground on which the engines were to be tried was a level piece of +railroad, about two miles in length. Each was required to make twenty +trips, or equal to a journey of seventy miles, in the course of the day, +and the average rate of travelling was to be not under ten miles an +hour. It was determined that, to avoid confusion, each engine should be +tried separately, and on different days. + +The day fixed for the competition was the 1st of October, but, to allow +sufficient time to get the locomotives into good working order, the +directors extended it to the 6th. It was quite characteristic of the +Stephensons that, although their engine did not stand first on the list +for trial, it was the first that was ready, and it was accordingly +ordered out by the judges for an experimental trip. Yet the "Rocket" was +by no means the "favourite" with either the judges or the spectators. +Nicholas Wood has since stated that the majority of the judges were +strongly predisposed in favour of the "Novelty," and that "nine-tenths, +if not ten-tenths, of the persons present were against the "Rocket" +because of its appearance." Nearly every person favoured some other +engine, so that there was nothing for the "Rocket" but the practical +test. The first trip made by it was quite successful. It ran about +twelve miles, without interruption, in about fifty-three minutes. + +The "Novelty" was next called out. It was a light engine, very compact +in appearance, carrying the water and fuel upon the same wheels as the +engine. The weight of the whole was only three tons and one +hundred-weight. A peculiarity of this engine was that the air was driven +or _forced_ through the fire by means of bellows. The day being now far +advanced, and some dispute having arisen as to the method of assigning +the proper load for the "Novelty," no particular experiment was made +further than that the engine traversed the line by way of exhibition, +occasionally moving at the rate of twenty-four miles an hour. The +"Sanspareil," constructed by Mr. Timothy Hackworth, was next exhibited, +but no particular experiment was made with it on this day. This engine +differed but little in its construction from the locomotive last +supplied by the Stephensons to the Stockton and Darlington Railway, of +which Mr. Hackworth was the locomotive foreman. + +The contest was postponed until the following day; but, before the +judges arrived on the ground, the bellows for creating the blast in the +"Novelty" gave way, and it was found incapable of going through its +performance. A defect was also detected in the boiler of the +"Sanspareil," and some further time was allowed to get it repaired. The +large number of spectators who had assembled to witness the contest were +greatly disappointed at this postponement; but, to lessen it, Stephenson +again brought out the "Rocket," and, attaching it to a coach containing +thirty persons, he ran them along the line at a rate of from twenty-four +to thirty miles an hour, much to their gratification and amazement. +Before separating, the judges ordered the engine to be in readiness by +eight o'clock on the following morning, to go through its definite trial +according to the prescribed conditions. + +On the morning of the 8th of October the "Rocket" was again ready for +the contest. The engine was taken to the extremity of the stage, the +fire-box was filled with coke, the fire lighted, and the steam raised +until it lifted the safety-valve loaded to a pressure of fifty pounds to +the square inch. This proceeding occupied fifty-seven minutes. The +engine then started on its journey, dragging after it about thirteen +tons' weight in waggons, and made the first ten trips backward and +forward along two miles of road, running the thirty-five miles, +including stoppages, in an hour and forty-eight minutes. The second ten +trips were in like manner performed in two hours and three minutes. The +maximum velocity attained during the trial trip was twenty-nine miles an +hour, or about three times the speed that one of the judges of the +competition had declared to be the limit of possibility. The average +speed at which the whole of the journeys was performed was fifteen miles +an hour, or five miles beyond the rate specified in the conditions +published by the company. The entire performance excited the greatest +astonishment among the assembled spectators; the directors felt +confident that their enterprise was now on the eve of success; and +George Stephenson rejoiced to think that, in spite of all false prophets +and fickle counsellors, the locomotive system was now safe. When the +"Rocket," having performed all the conditions of the contest, arrived at +the "grand stand" at the close of its day's successful run, Mr. +Cropper--one of the directors favourable to the fixed engine +system--lifted up his hands, and exclaimed, "Now has George Stephenson +at last delivered himself...." + +The "Rocket" had eclipsed the performance of all locomotive engines that +had yet been constructed, and outstripped even the sanguine expectations +of its constructors. It satisfactorily answered the report of Messrs. +Walker and Rastrick, and established the efficiency of the locomotive +for working the Liverpool and Manchester Railway, and, indeed, all +future railways. The "Rocket" showed that a new power had been born into +the world, full of activity and strength, with boundless capability of +work. It was the simple but admirable contrivance of the steam-blast, +and its combination with the multitubular boiler, that at once gave +locomotion a vigorous life, and secured the triumph of the railway +system.[8] + +[Illustration: The "Rocket"] + + +FOOTNOTES: + +[7] The conditions were these: + +1. The engine must effectually consume its own smoke. + +2. The engine, if of six tons' weight, must be able to draw after it, +day by day, twenty tons' weight (including the tender and water-tank) at +_ten miles_ an hour, with a pressure of steam on the boiler not +exceeding fifty pounds to the square inch. + +3. The boiler must have two safety-valves, neither of which must be +fastened down, and one of them be completely out of the control of the +engine-man. + +4. The engine and boiler must be supported on springs, and rest on six +wheels, the height of the whole not exceeding fifteen feet to the top of +the chimney. + +5. The engine, with water, must not weigh more than six tons; but an +engine of less weight would be preferred on its drawing a proportionate +load behind it; if of only four and a half tons, then it might be put on +only four wheels. The company will be at liberty to test the boiler, +etc., by a pressure of one hundred and fifty pounds to the square inch. + +6. A mercurial gauge must be affixed to the machine, showing the steam +pressure above forty-five pounds per square inch. + +7. The engine must be delivered, complete and ready for trial, at the +Liverpool end of the railway, not later than the 1st of October, 1829. + +8. The price of the engine must not exceed L550. + +Many persons of influence declared the conditions published by the +directors of the railway chimerical in the extreme. One gentleman of +some eminence in Liverpool, Mr. P. Ewart, who afterward filled the +office of Government Inspector of Post-office Steam Packets, declared +that only a parcel of charlatans would ever have issued such a set of +conditions; that it had been _proved_ to be impossible to make a +locomotive engine go at ten miles an hour; but if it ever was done, he +would undertake to eat a stewed engine-wheel for his breakfast. + +[8] When heavier and more powerful engines were brought upon the road, +the old "Rocket," becoming regarded as a thing of no value, was sold in +1837. It has since been transferred to the Museum of Patents at South +Kensington, London, where it is still to be seen. + + +Transcriber's Notes: + +Page 30--imployed changed to employed. + +Page 31--subsequenty changed to subsequently. + +Page 47--build changed to building. + +Page 147--suggestor changed to suggester. + +Page 166--supgestion changed to suggestion. + +Footnote 7--Changed question mark for a period. + +Inconsistencies in hyphenated words have been made consistent. + +Obvious printer errors, including punctuation, have been corrected +without note. + + + + + +End of Project Gutenberg's Little Masterpieces of Science:, by Various + +*** END OF THIS PROJECT GUTENBERG EBOOK LITTLE MASTERPIECES OF SCIENCE: *** + +***** This file should be named 29241.txt or 29241.zip ***** +This and all associated files of various formats will be found in: + http://www.gutenberg.org/2/9/2/4/29241/ + +Produced by Sigal Alon, Marcia Brooks, Fox in the Stars +and the Online Distributed Proofreading Team at +http://www.pgdp.net + + +Updated editions will replace the previous one--the old editions +will be renamed. + +Creating the works from public domain print editions means that no +one owns a United States copyright in these works, so the Foundation +(and you!) can copy and distribute it in the United States without +permission and without paying copyright royalties. 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