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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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