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diff --git a/29444.txt b/29444.txt new file mode 100644 index 0000000..e13ea66 --- /dev/null +++ b/29444.txt @@ -0,0 +1,3251 @@ +Project Gutenberg's The Machinery of the Universe, by Amos Emerson Dolbear + +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: The Machinery of the Universe + Mechanical Conceptions of Physical Phenomena + +Author: Amos Emerson Dolbear + +Release Date: July 18, 2009 [EBook #29444] + +Language: English + +Character set encoding: ASCII + +*** START OF THIS PROJECT GUTENBERG EBOOK THE MACHINERY OF THE UNIVERSE *** + + + + +Produced by Chris Curnow, Andrew D. Hwang, and the Online +Distributed Proofreading Team at https://www.pgdp.net (This +file was produced from images generously made available +by The Internet Archive) + + + + + + + + + +_THE ROMANCE OF SCIENCE_ + + +THE MACHINERY OF THE UNIVERSE + +MECHANICAL CONCEPTIONS OF +PHYSICAL PHENOMENA + + +BY +A. E. DOLBEAR, A.B., A.M., M.E., PH.D. + +PROFESSOR OF PHYSICS AND ASTRONOMY, TUFTS COLLEGE, MASS. + + +PUBLISHED UNDER GENERAL LITERATURE COMMITTEE. + + +LONDON: +SOCIETY FOR PROMOTING CHRISTIAN KNOWLEDGE, +NORTHUMBERLAND AVENUE, W.C.; +43, QUEEN VICTORIA STREET, E.C. + +BRIGHTON: 129, NORTH STREET. + +NEW YORK: E. & J. B. YOUNG & CO. + +1897. + + + + +PREFACE + + +For thirty years or more the expressions "Correlation of the Physical +Forces" and "The Conservation of Energy" have been common, yet few +persons have taken the necessary pains to think out clearly what +mechanical changes take place when one form of energy is transformed +into another. + +Since Tyndall gave us his book called _Heat as a Mode of Motion_ neither +lecturers nor text-books have attempted to explain how all phenomena are +the necessary outcome of the various forms of motion. In general, +phenomena have been attributed to _forces_--a metaphysical term, which +explains nothing and is merely a stop-gap, and is really not at all +needful in these days, seeing that transformable modes of motion, easily +perceived and understood, may be substituted in all cases for forces. + +In December 1895 the author gave a lecture before the Franklin Institute +of Philadelphia, on "Mechanical Conceptions of Electrical Phenomena," in +which he undertook to make clear what happens when electrical phenomena +appear. The publication of this lecture in _The Journal of the Franklin +Institute_ and in _Nature_ brought an urgent request that it should be +enlarged somewhat and published in a form more convenient for the +public. The enlargement consists in the addition of a chapter on the +"_Contrasted Properties of Matter and the Ether_," a chapter containing +something which the author believes to be of philosophical importance in +these days when electricity is so generally described as a phenomenon of +the ether. + +A. E. DOLBEAR. + + + + +TABLE OF CONTENTS + + +CHAPTER I + +Ideas of phenomena ancient and modern, metaphysical and + mechanical--Imponderables--Forces, invented and + discarded--Explanations--Energy, its factors, Kinetic + and Potential--Motions, kinds and transformations + of--Mechanical, molecular, and atomic--Invention of + Ethers, Faraday's conceptions p. 7 + + +CHAPTER II + +Properties of Matter and Ether compared--Discontinuity + _versus_ Continuity--Size of atoms--Astronomical + distances--Number of atoms in the universe--Ether + unlimited--Kinds of Matter, permanent qualities + of--Atomic structure; vortex-rings, their + properties--Ether structureless--Matter + gravitative, Ether not--Friction in Matter, Ether + frictionless--Chemical properties--Energy in + Matter and in Ether--Matter as a transformer + of Energy--Elasticity--Vibratory rates and + waves--Density--Heat--Indestructibility of + Matter--Inertia in Matter and in Ether--Matter + not inert--Magnetism and Ether waves--States + of Matter--Cohesion and chemism affected by + temperature--Shearing stress in Solids and in + Ether--Ether pressure--Sensation dependent upon + Matter--Nervous system not affected by Ether + states--Other stresses in Ether--Transformations + of Motion--Terminology p. 24 + + +CHAPTER III + +Antecedents of Electricity--Nature of what is + transformed--Series of transformations for the + production of light--Positive and negative + Electricity--Positive and negative twists--Rotations + about a wire--Rotation of an arc--Ether a + non-conductor--Electro-magnetic waves--Induction + and inductive action--Ether stress and atomic + position--Nature of an electric current--Electricity + a condition, not an entity p. 94 + + + + +CHAPTER I + +Ideas of phenomena ancient and modern, metaphysical and + mechanical--Imponderables--Forces, invented and + discarded--Explanations--Energy, its factors, Kinetic + and Potential--Motions, kinds and transformations + of--Mechanical, molecular, and atomic--Invention of + Ethers, Faraday's conceptions. + +'And now we might add something concerning a most subtle spirit + which pervades and lies hid in all gross bodies, by the force + and action of which spirit the particles of bodies attract + each other at near distances, and cohere if contiguous, and + electric bodies operate at greater distances, as well repelling + as attracting neighbouring corpuscles, and light is emitted, + reflected, inflected, and heats bodies, and all sensation is + excited, and members of animal bodies move at the command of + the will.'--NEWTON, _Principia_. + + +In Newton's day the whole field of nature was practically lying fallow. +No fundamental principles were known until the law of gravitation was +discovered. This law was behind all the work of Copernicus, Kepler, and +Galileo, and what they had done needed interpretation. It was quite +natural that the most obvious and mechanical phenomena should first be +reduced, and so the _Principia_ was concerned with mechanical principles +applied to astronomical problems. To us, who have grown up familiar with +the principles and conceptions underlying them, all varieties of +mechanical phenomena seem so obvious, that it is difficult for us to +understand how any one could be obtuse to them; but the records of +Newton's time, and immediately after this, show that they were not so +easy of apprehension. It may be remembered that they were not adopted in +France till long after Newton's day. In spite of what is thought to be +reasonable, it really requires something more than complete +demonstration to convince most of us of the truth of an idea, should the +truth happen to be of a kind not familiar, or should it chance to be +opposed to our more or less well-defined notions of what it is or ought +to be. If those who labour for and attain what they think to be the +truth about any matter, were a little better informed concerning mental +processes and the conditions under which ideas grow and displace others, +they would be more patient with mankind; teachers of every rank might +then discover that what is often called stupidity may be nothing else +than mental inertia, which can no more be made active by simply willing +than can the movement of a cannon ball by a like effort. We _grow_ into +our beliefs and opinions upon all matters, and scientific ideas are no +exceptions. + +Whewell, in his _History of the Inductive Sciences_, says that the +Greeks made no headway in physical science because they lacked +appropriate ideas. The evidence is overwhelming that they were as +observing, as acute, as reasonable as any who live to-day. With this +view, it would appear that the great discoverers must have been men who +started out with appropriate ideas: were looking for what they found. +If, then, one reflects upon the exceeding great difficulty there is in +discovering one new truth, and the immense amount of work needed to +disentangle it, it would appear as if even the most successful have but +indistinct ideas of what is really appropriate, and that their +mechanical conceptions become clarified by doing their work. This is not +always the fact. In the statement of Newton quoted at the head of this +chapter, he speaks of a spirit which lies hid in all gross bodies, etc., +by means of which all kinds of phenomena are to be explained; but he +deliberately abandons that idea when he comes to the study of light, for +he assumes the existence and activity of light corpuscles, for which he +has no experimental evidence; and the probability is that he did this +because the latter conception was one which he could handle +mathematically, while he saw no way for thus dealing with the other. His +mechanical instincts were more to be trusted than his carefully +calculated results; for, as all know, what he called "spirits," is what +to-day we call the ether, and the corpuscular theory of light has now no +more than a historic interest. The corpuscular theory was a mechanical +conception, but each such corpuscle was ideally endowed with qualities +which were out of all relation with the ordinary matter with which it +was classed. + +Until the middle of the present century the reigning physical philosophy +held to the existence of what were called imponderables. The phenomena +of heat were explained as due to an imponderable substance called +"caloric," which ordinary matter could absorb and emit. A hot body was +one which had absorbed an imponderable substance. It was, therefore, no +heavier than before, but it possessed ability to do work proportional to +the amount absorbed. Carnot's ideal engine was described by him in terms +that imply the materiality of heat. Light was another imponderable +substance, the existence of which was maintained by Sir David Brewster +as long as he lived. Electricity and magnetism were imponderable fluids, +which, when allied with ordinary matter, endowed the latter with their +peculiar qualities. The conceptions in each case were properly +mechanical ones _part_ (but not all) _of the time_; for when the +immaterial substances were dissociated from matter, where they had +manifested themselves, no one concerned himself to inquire as to their +whereabouts. They were simply off duty, but could be summoned, like the +genii in the story of Aladdin's Lamp. Now, a mechanical conception of +any phenomenon, or a mechanical explanation of any kind of action, must +be mechanical all the time, in the antecedents as well as the +consequents. Nothing else will do except a miracle. + +During the fifty years, from about 1820 to 1870, a somewhat different +kind of explanation of physical events grew up. The interest that was +aroused by the discoveries in all the fields of physical science--in +heat, electricity, magnetism and chemistry--by Faraday, Joule, +Helmholtz, and others, compelled a change of conceptions; for it was +noticed that each special kind of phenomenon was preceded by some other +definite and known kind; as, for instance, that chemical action preceded +electrical currents, that mechanical or electrical activity resulted +from changing magnetism, and so on. As each kind of action was believed +to be due to a special force, there were invented such terms as +mechanical force, electrical force, magnetic, chemical and vital forces, +and these were discovered to be convertible into one another, and the +"doctrine of the correlation of the physical forces" became a common +expression in philosophies of all sorts. By "convertible into one +another," was meant, that whenever any given force appeared, it was at +the expense of some other force; thus, in a battery chemical force was +changed into electrical force; in a magnet, electrical force was changed +into magnetic force, and so on. The idea here was the _transformation of +forces_, and _forces_ were not so clearly defined that one could have a +mechanical idea of just what had happened. That part of the philosophy +was no clearer than that of the imponderables, which had largely dropped +out of mind. The terminology represented an advance in knowledge, but +was lacking in lucidity, for no one knew what a force of any kind was. + +The first to discover this and to repudiate the prevailing terminology +were the physiologists, who early announced their disbelief in a vital +force, and their belief that all physiological activities were of purely +physical and chemical origin, and that there was no need to assume any +such thing as a vital force. Then came the discovery that chemical +force, or affinity, had only an adventitious existence, and that, at +absolute zero, there was no such activity. The discovery of, or rather +the appreciation of, what is implied by the term _absolute zero_, and +especially of the nature of heat itself, as expressed in the statement +that heat is a mode of motion, dismissed another of the so-called forces +as being a metaphysical agency having no real existence, though standing +for phenomena needing further attention and explanation; and by +explanation is meant _the presentation of the mechanical antecedents for +a phenomenon, in so complete a way that no supplementary or unknown +factors are necessary_. The train moves because the engine pulls it; the +engine pulls because the steam pushes it. There is no more necessity for +assuming a steam force between the steam and the engine, than for +assuming an engine force between the engine and the train. All the +processes are mechanical, and have to do only with ordinary matter and +its conditions, from the coal-pile to the moving freight, though there +are many transformations of the forms of motion and of energy between +the two extremes. + +During the past thirty years there has come into common use another +term, unknown in any technical sense before that time, namely, _energy_. +What was once called the conservation of force is now called the +conservation of energy, and we now often hear of forms of energy. Thus, +heat is said to be a form of energy, and the forms of energy are +convertible into one another, as the so-called forces were formerly +supposed to be transformable into one another. We are asked to consider +gravitative energy, heat energy, mechanical energy, chemical energy, and +electrical energy. When we inquire what is meant by energy, we are +informed that it means ability to do work, and that work is measurable +as a pressure into a distance, and is specified as foot-pounds. A mass +of matter moves because energy has been spent upon it, and has acquired +energy equal to the work done on it, and this is believed to hold true, +no matter what the kind of energy was that moved it. If a body moves, it +moves because another body has exerted pressure upon it, and its energy +is called _kinetic energy_; but a body may be subject to pressure and +not move appreciably, and then the body is said to possess potential +energy. Thus, a bent spring and a raised weight are said to possess +potential energy. In either case, _an energized body receives its energy +by pressure, and has ability to produce pressure on another body_. +Whether or not it does work on another body depends on the rigidity of +the body it acts upon. In any case, it is simply a mechanical +action--body A pushes upon body B (Fig. 1). There is no need to assume +anything more mysterious than mechanical action. Whether body B moves +this way or that depends upon the direction of the push, the point of +its application. Whether the body be a mass as large as the earth or as +small as a molecule, makes no difference in that particular. Suppose, +then, that _a_ (Fig. 2) spends its energy on _b_, _b_ on _c_, _c_ on +_d_, and so on. The energy of _a_ gives translatory motion to _b_, _b_ +sets _c_ vibrating, and _c_ makes _d_ spin on some axis. Each of these +has had energy spent on it, and each has some form of energy different +from the other, but no new factor has been introduced between _a_ and +_d_, and the only factor that has gone from _a_ to _d_ has been +motion--motion that has had its direction and quality changed, but not +its nature. If we agree that energy is neither created nor annihilated, +by any physical process, and if we assume that _a_ gave to _b_ all its +energy, that is, all its motion; that _b_ likewise gave its all to _c_, +and so on; then the succession of phenomena from _a_ to _d_ has been +simply the transference of a definite amount of motion, and therefore of +energy, from the one to the other; for _motion has been the only +variable factor_. If, furthermore, we should agree to call the +translatory motion [alpha], the vibratory motion [beta], the +rotary [gamma], then we should have had a conversion of [alpha] +into [beta], of [beta] into [gamma]. If we should consider +the amount of transfer motion instead of the kind of motion, we should +have to say that the [alpha] energy had been transformed into +[beta] and the [beta] into [gamma]. + +[Illustration: FIG. 1.] + +[Illustration: FIG. 2.] + +What a given amount of energy will do depends only upon its _form_, that +is, the kind of motion that embodies it. + +The energy spent upon a stone thrown into the air, giving it translatory +motion, would, if spent upon a tuning fork, make it sound, but not move +it from its place; while if spent upon a top, would enable the latter to +stand upon its point as easily as a person stands on his two feet, and +to do other surprising things, which otherwise it could not do. One can, +without difficulty, form a mechanical conception of the whole series +without assuming imponderables, or fluids or forces. Mechanical motion +only, by pressure, has been transferred in certain directions at certain +rates. Suppose now that some one should suddenly come upon a spinning +top (Fig. 3) while it was standing upon its point, and, as its motion +might not be visible, should cautiously touch it. It would bound away +with surprising promptness, and, if he were not instructed in the +mechanical principles involved, he might fairly well draw the conclusion +that it was actuated by other than simple mechanical principles, and, +for that reason, it would be difficult to persuade him that there was +nothing essentially different in the body that appeared and acted thus, +than in a stone thrown into the air; nevertheless, that statement would +be the simple truth. + +[Illustration: FIG. 3.] + +All our experience, without a single exception, enforces the proposition +that no body moves in any direction, or in any way, except when some +other body _in contact_ with it presses upon it. The action is direct. +In Newton's letter to his friend Bentley, he says--"That one body +should act upon another through empty space, without the mediation of +anything else by and through which their action and pressure may be +conveyed from one to another, is to me so great an absurdity that I +believe no man who has in philosophical matters a competent faculty of +thinking can ever fall into it." + +For mathematical purposes, it has sometimes been convenient to treat a +problem as if one body could act upon another without any physical +medium between them; but such a conception has no degree of rationality, +and I know of no one who believes in it as a fact. If this be granted, +then our philosophy agrees with our experience, and every body moves +because it is pushed, and the mechanical antecedent of every kind of +phenomenon is to be looked for in some adjacent body possessing +energy--that is, the ability to push or produce pressure. + +It must not be forgotten that energy is not a simple factor, but is +always a product of two factors--a mass with a velocity, a mass with a +temperature, a quantity of electricity into a pressure, and so on. One +may sometimes meet the statement that matter and energy are the two +realities; both are spoken of as entities. It is much more philosophical +to speak of matter and motion, for in the absence of motion there is no +energy, and the energy varies with the amount of motion; and +furthermore, to understand any manifestation of energy one must inquire +what kind of motion is involved. This we do when we speak of mechanical +energy as the energy involved in a body having a translatory motion; +also, when we speak of heat as a vibratory, and of light as a wave +motion. To speak of energy without stating or implying these +distinctions, is to speak loosely and to keep far within the bounds of +actual knowledge. To speak thus of a body possessing energy, or +expending energy, is to imply that the body possesses some kind of +motion, and produces pressure upon another body because it has motion. +Tait and others have pointed out the fact, that what is called potential +energy must, in its nature, be kinetic. Tait says--"Now it is impossible +to conceive of a truly dormant form of energy, whose magnitude should +depend, in any way, upon the unit of time; and we are forced to conclude +that potential energy, like kinetic energy, depends (even if unexplained +or unimagined) upon motion." All this means that it is now too late to +stop with energy as a final factor in any phenomenon, that the _form of +motion_ which embodies the energy is the factor that determines _what_ +happens, as distinguished from how _much_ happens. Here, then, are to be +found the distinctions which have heretofore been called forces; here +is embodied the proof that direct pressure of one body upon another is +what causes the latter to move, and that the direction of movement +depends on the point of application, with reference to the centre +of mass. + +It is needful now to look at the other term in the product we call +energy, namely, the substance moving, sometimes called matter or mass. +It has been mentioned that the idea of a medium filling space was +present to Newton, but his gravitation problem did not require that he +should consider other factors than masses and distances. The law of +gravitation as considered by him was--Every particle of matter attracts +every other particle of matter with a stress which is proportional to +the product of their masses, and inversely to the squares of the +distance between them. Here we are concerned only with the statement +that every particle of matter attracts every other particle of matter. +Everything then that possesses gravitative attraction is matter in the +sense in which that term is used in this law. If there be any other +substance in the universe that is not thus subject to gravitation, then +it is improper to call it matter, otherwise the law should read, "Some +particles of matter attract," etc., which will never do. + +We are now assured that there is something else in the universe which +has no gravitative property at all, namely, the ether. It was first +imagined in order to account for the phenomena of light, which was +observed to take about eight minutes to come from the sun to the earth. +Then Young applied the wave theory to the explanation of polarization +and other phenomena; and in 1851 Foucault proved experimentally that the +velocity of light was less in water than in air, as it should be if the +wave theory be true, and this has been considered a crucial experiment +which took away the last hope for the corpuscular theory, and +demonstrated the existence of the ether as a space-filling medium +capable of transmitting light-waves known to have a velocity of 186,000 +miles per second. It was called the luminiferous ether, to distinguish +it from other ethers which had also been imagined, such as electric +ether for electrical phenomena, magnetic ether for magnetic phenomena, +and so on--as many ethers, in fact, as there were different kinds of +phenomena to be explained. + +It was Faraday who put a stop to the invention of ethers, by suggesting +that the so-called luminiferous ether might be the one concerned in all +the different phenomena, and who pointed out that the arrangement of +iron filings about a magnet was indicative of the direction of the +stresses in the ether. This suggestion did not meet the approval of the +mathematical physicists of his day, for it necessitated the abandonment +of the conceptions they had worked with, as well as the terminology +which had been employed, and made it needful to reconstruct all their +work to make it intelligible--a labour which was the more distasteful as +it was forced upon them by one who, although expert enough in +experimentation, was not a mathematician, and who boasted that the most +complicated mathematical work he ever did was to turn the crank of a +calculating machine; who did all his work, formed his conclusions, and +then said--"The work is done; hand it over to the computers." + +It has turned out that Faraday's mechanical conceptions were right. +Every one now knows of Maxwell's work, which was to start with Faraday's +conceptions as to magnetic phenomena, and follow them out to their +logical conclusions, applying them to molecules and the reactions of the +latter upon the ether. Thus he was led to conclude that light was an +electro-magnetic phenomenon; that is, that the waves which constitute +light, and the waves produced by changing magnetism were identical in +their nature, were in the same medium, travelled with the same velocity, +were capable of refraction, and so on. Now that all this is a matter of +common knowledge to-day, it is curious to look back no further than ten +years. Maxwell's conclusions were adopted by scarcely a physicist in +the world. Although it was known that inductive action travelled with +finite velocity in space, and that an electro-magnet would affect the +space about it practically inversely as the square of the distance, and +that such phenomena as are involved in telephonic induction between +circuits could have no other meaning than the one assigned by Maxwell, +yet nearly all the physicists failed to form the only conception of it +that was possible, and waited for Hertz to devise apparatus for +producing interference before they grasped it. It was even then so new, +to some, that it was proclaimed to be a demonstration of the existence +of the ether itself, as well as a method of producing waves short enough +to enable one to notice interference phenomena. It is obvious that Hertz +himself must have had the mechanics of wave-motion plainly in mind, or +he would not have planned such experiments. The outcome of it all is, +that we now have experimental demonstration, as well as theoretical +reason for believing, that the ether, once considered as only +luminiferous, is concerned in all electric and magnetic phenomena, and +that waves set up in it by electro-magnetic actions are capable of being +reflected, refracted, polarized, and twisted, in the same way as +ordinary light-waves can be, and that the laws of optics are applicable +to both. + + + + +CHAPTER II + +PROPERTIES OF MATTER AND ETHER + +Properties of Matter and Ether compared--Discontinuity + _versus_ Continuity--Size of atoms--Astronomical + distances--Number of atoms in the universe--Ether + unlimited--Kinds of Matter, permanent qualities + of--Atomic structure; vortex-rings, their + properties--Ether structureless--Matter + gravitative, Ether not--Friction in Matter, Ether + frictionless--Chemical properties--Energy in + Matter and in Ether--Matter as a transformer + of Energy--Elasticity--Vibratory rates and + waves--Density--Heat--Indestructibility of + Matter--Inertia in Matter and in Ether--Matter + not inert--Magnetism and Ether waves--States + of Matter--Cohesion and chemism affected by + temperature--Shearing stress in Solids and in + Ether--Ether pressure--Sensation dependent upon + Matter--Nervous system not affected by Ether + states--Other stresses in Ether--Transformations + of Motion--Terminology. + + +A common conception of the ether has been that it is a finer-grained +substance than ordinary matter, but otherwise so like the latter that +the laws found to hold good with matter were equally applicable to the +ether, and hence the mechanical conceptions formed from experience in +regard to the one have been transferred to the other, and the properties +belonging to one, such as density, elasticity, etc., have been asserted +as properties of the other. + +There is so considerable a body of knowledge bearing upon the +similarities and dissimilarities of these two entities that it will be +well to compare them. After such comparison one will be better able to +judge of the propriety of assuming them to be subject to identical laws. + + +1. MATTER IS DISCONTINUOUS. + +Matter is made up of atoms having dimensions approximately determined to +be in the neighbourhood of the one fifty-millionth of an inch in +diameter. These atoms may have various degrees of aggregation;--they may +be in practical contact, as in most solid bodies such as metals and +rocks; in molecular groupings as in water, and in gases such as +hydrogen, oxygen, and so forth, where two, three, or more atoms cohere +so strongly as to enable the molecules to act under ordinary +circumstances like simple particles. Any or all of these molecules and +atoms may be separated by any assignable distance from each other. Thus, +in common air the molecules, though rapidly changing their positions, +are on the average about two hundred and fifty times their own diameter +apart. This is a distance relatively greater than the distance apart of +the earth and the moon, for two hundred and fifty times the diameter of +the earth will be 8000 x 250 = 2,000,000 miles, while the distance to +the moon is but 240,000 miles. The sun is 93,000,000 miles from the +earth, and the most of the bodies of the solar system are still more +widely separated, Neptune being nearly 3000 millions of miles from the +sun. As for the fixed stars, they are so far separated from us that, at +the present rate of motion of the solar system in its drift through +space--500 millions of miles in a year--it would take not less than +40,000 years to reach the nearest star among its neighbours, while for +the more remote ones millions of years must be reckoned. The huge space +separating these masses is practically devoid of matter; it is a vacuum. + + +THE ETHER IS CONTINUOUS. + +The idea of continuity as distinguished from discontinuity may be gained +by considering what would be made visible by magnification. Water +appears to the eye as if it were without pores, but if sugar or salt be +put into it, either will be dissolved and quite disappear among the +molecules of the water as steam does in the air, which shows that there +are some unoccupied spaces between the molecules. If a microscope be +employed to magnify a minute drop of water it still shows the same lack +of structure as that looked at with the unaided eye. If the magnifying +power be the highest it may reveal a speck as small as the +hundred-thousandth part of an inch, yet the speck looks no different in +character. We know that water is composed of two different kinds of +atoms, hydrogen and oxygen, for they can be separated by chemical means +and kept in separate bottles, and again made to combine to form water +having all the qualities that belonged to it before it was decomposed. +If a very much higher magnifying power were available, we should +ultimately be able to see the individual water molecules, and recognize +their hydrogen and oxygen constituents by their difference in size, rate +of movements, and we might possibly separate them by mechanical methods. +What one would see would be something very different in structure from +the water as it appears to our eyes. If the ether were similarly to be +examined through higher and still higher magnifying powers, even up to +infinity, there is no reason for thinking that the last examination +would show anything different in structure or quality from that which +was examined with low power or with no microscope at all. This is all +expressed by saying that the ether is a continuous substance, without +interstices, that it fills space completely, and, unlike gases, +liquids, and solids, is incapable of absorbing or dissolving anything. + + +2. MATTER IS LIMITED. + +There appears to be a definite amount of matter in the visible universe, +a definite number of molecules and atoms. How many molecules there are +in a cubic inch of air under ordinary pressure has been determined, and +is represented approximately by a huge number, something like a thousand +million million millions. + +When the diameter of a molecule has been measured, as it has been +approximately, and found to be about one fifty-millionth of an inch, +then fifty million in a row would reach an inch, and the cube of fifty +million is 125,000,000000,000000,000000, one hundred and twenty-five +thousand million million millions. In a cubic foot there will of course +be 1728 times that number. One may if one likes find how many there may +be in the earth, and moon, sun and planets, for the dimensions of them +are all very well known. Only the multiplication table need be used, and +the sum of all these will give how many molecules there are in the solar +system. If one should feel that the number thus obtained was not very +accurate, he might reflect that if there were ten times as many it would +add but another cipher to a long line of similar ones and would not +materially modify it. The point is that there is a definite, computable +number. If one will then add to these the number of molecules in the +more distant stars and nebulae, of which there are visible about +100,000,000, making such estimate of their individual size as he thinks +prudent, the sum of all will give the number of molecules in the visible +universe. The number is not so large but it can be written down in a +minute or two. Those who have been to the pains to do the sum say it may +be represented by seven followed by ninety-one ciphers. One could easily +compute how many molecules so large a space would contain if it were +full and as closely packed as they are in a drop of water, but there +would be a finite and not an infinite number, and therefore there is a +limited number of atoms in the visible universe. + + +THE ETHER IS UNLIMITED. + +The evidence for this comes to us from the phenomena of light. +Experimentally, ether waves of all lengths are found to have a velocity +of 186,000 miles in a second. It takes about eight minutes to reach us +from the sun, four hours from Neptune the most distant planet, and from +the nearest fixed star about three and a half years. Astronomers tell us +that some visible stars are so distant that their light requires not +less than ten thousand years and probably more to reach us, though +travelling at the enormous rate of 186,000 miles a second. This means +that the whole of space is filled with this medium. If there were any +vacant spaces, the light would fail to get through them, and stars +beyond them would become invisible. There are no such vacant spaces, for +any part of the heavens shows stars beaming continuously, and every +increase in telescopic power shows stars still further removed than any +seen before. The whole of this intervening space must therefore be +filled with the ether. Some of the waves that reach us are not more than +the hundred-thousandth of an inch long, so there can be no crack or +break or absence of ether from so small a section as the +hundred-thousandth of an inch in all this great expanse. More than this. +No one can think that the remotest visible stars are upon the boundary +of space, that if one could get to the most distant star he would have +on one side the whole of space while the opposite side would be devoid +of it. Space we know is of three dimensions, and a straight line may be +prolonged in any direction to an infinite distance, and a ray of light +may travel on for an infinite time and come to no end provided space be +filled with ether. + +How long the sun and stars have been shining no one knows, but it is +highly probable that the sun has existed for not less than 1000 million +years, and has during that time been pouring its rays as radiant energy +into space. If then in half that time, or 500 millions of years, the +light had somewhere reached a boundary to the ether, it could not have +gone beyond but would have been reflected back into the ether-filled +space, and such part of the sky would be lit up by this reflected light. +There is no indication that anything like reflection comes to us from +the sky. This is equivalent to saying that the ether fills space in +every direction away from us to an unlimited distance, and so far is +itself unlimited. + + +3. MATTER IS HETEROGENEOUS. + +The various kinds of matter we are acquainted with are commonly called +the elements. These when combined in various ways exhibit characteristic +phenomena which depend upon the kinds of matter, the structure and +motions which are involved. There are some seventy different kinds of +this elemental matter which may be identified as constituents of the +earth. Many of the same elements have been identified in the sun and +stars, such for instance as hydrogen, carbon, and iron. Such phenomena +lead us to conclude that the kinds of matter elsewhere in the universe +are identical with such as we are familiar with, and that elsewhere the +variety is as great. The qualities of the elements, within a certain +range of temperature, are permanent; they are not subject to +fluctuations, though the qualities of combinations of them may vary +indefinitely. The elements therefore may be regarded as retaining their +identity in all ordinary experience. + + +THE ETHER IS HOMOGENEOUS. + +One part of the ether is precisely like any other part everywhere and +always, and there are no such distinctions in it as correspond with the +elemental forms of matter. + + +4. MATTER IS ATOMIC. + +There is an ultimate particle of each one of the elements which is +practically absolute and known as an atom. The atom retains its identity +through all combinations and processes. It may be here or there, move +fast or slow, but its atomic form persists. + + +THE ETHER IS NON-ATOMIC. + +One might infer, from what has already been said about continuity, that +the ether could not be constituted of separable particles like masses of +matter; for no matter how minute they might be, there would be +interspaces and unoccupied spaces which would present us with phenomena +which have never been seen. It is the general consensus of opinion +among those who have studied the subject that the ether is not atomic in +structure. + + +5. MATTER HAS DEFINITE STRUCTURE. + +Every atom of every element is so like every other atom of the same +element as to exhibit the same characteristics, size, weight, chemical +activity, vibratory rate, etc., and it is thus shown conclusively that +the structural form of the elemental particles is the same for each +element, for such characteristic reactions as they exhibit could hardly +be if they were mechanically unlike. + +Of what form the atoms of an element may be is not very definitely +known. The earlier philosophers assumed them to be hard round particles, +but later thinkers have concluded that atoms of such a character are +highly improbable, for they could not exhibit in this case the +properties which the elements do exhibit. They have therefore dismissed +such a conception from consideration. In place of this hypothesis has +been substituted a very different idea, namely, that an atom is a +vortex-ring[1] of ether floating in the ether, as a smoke-ring puffed +out by a locomotive in still air may float in the air and show various +phenomena. + +[Footnote 1: Vortex-rings for illustration may be made by having a +wooden box about a foot on a side, with a round orifice in the middle of +one side, and the side opposite covered with stout cloth stretched tight +over a framework. A saucer containing strong ammonia water, and another +containing strong hydrochloric acid, will cause dense fumes in the box, +and a tap with the hand upon the cloth back will force out a ring from +the orifice. These may be made to follow and strike each other, +rebounding and vibrating, apparently attracting each other and being +attracted by neighbouring bodies. + +By filling the mouth with smoke, and pursing the lips as if to make the +sound _o_, one may make fifteen or twenty small rings by snapping the +cheek with the finger.] + +A vortex-ring produced in the air behaves in the most surprising manner. + +[Illustration: FIG. 4.--Method of making vortex-rings and their +behaviour.] + +1. It retains its ring form and the same material rotating as it +starts with. + +2. It can travel through the air easily twenty or thirty feet in a +second without disruption. + +3. Its line of motion when free is always at right angles to the +plane of the ring. + +4. It will not stand still unless compelled by some object. If +stopped in the air it will start up itself to travel on without +external help. + +5. It possesses momentum and energy like a solid body. + +6. It is capable of vibrating like an elastic body, making a +definite number of such vibrations per second, the degree of +elasticity depending upon the rate of vibration. The swifter the +rotation, the more rigid and elastic it is. + +7. It is capable of spinning on its own axis, and thus having rotary +energy as well as translatory and vibratory. + +8. It repels light bodies in front of it, and attracts into itself +light bodies in its rear. + +9. If projected along parallel with the top of a long table, it will +fall upon it every time, just as a stone thrown horizontally will +fall to the ground. + +10. If two rings of the same size be travelling in the same line, +and the rear one overtakes the other, the front one will enlarge its +diameter, while the rear one will contract its own till it can go +through the forward one, when each will recover its original +diameter, and continue on in the same direction, but vibrating, +expanding and contracting their diameters with regularity. + +11. If two rings be moving in the same line, but in opposite +directions, they will repel each other when near, and thus retard +their speed. If one goes through the other, as in the former case, +it may quite lose its velocity, and come to a standstill in the air +till the other has moved on to a distance, when it will start up in +its former direction. + +12. If two rings be formed side by side, they will instantly collide +at their edges, showing strong attraction. + +13. If the collision does not destroy them, they may either break +apart at the point of the collision, and then weld together into a +single ring with twice the diameter, and then move on as if a single +ring had been formed, or they may simply bounce away from each +other, in which case they always rebound _in a plane_ at right +angles to the plane of collision. That is, if they collided on their +sides, they would rebound so that one went up and the other down. + +14. Three may in like manner collide and fuse into a single ring. + +Such rings formed in air by a locomotive may rise wriggling in the air +to the height of several hundred feet, but they are soon dissolved and +disappear. This is because the friction and viscosity of the air robs +the rings of their substance and energy. If the air were without +friction this could not happen, and the rings would then be persistent, +and would retain all their qualities. + +Suppose then that such rings were produced in a medium without friction +as the ether is believed to be, they would be permanent structures with +a variety of properties. They would occupy space, have definite form and +dimensions, momentum, energy, attraction and repulsion, elasticity; obey +the laws of motion, and so far behave quite like such matter as we know. +For such reasons it is thought by some persons to be not improbable +that the atoms of matter are minute vortex-rings of ether in the ether. +That which distinguishes the atom from the ether is the form of motion +which is embodied in it, and if the motion were simply arrested, there +would be nothing to distinguish the atom from the ether into which it +dissolved. In other words, such a conception makes the atoms of matter a +form of motion of the ether, and not a created something put into the +ether. + + +THE ETHER IS STRUCTURELESS. + +If the ether be the boundless substance described, it is clear it can +have no form as a whole, and if it be continuous it can have no minute +structure. If not constituted of atoms or molecules there is nothing +descriptive that can be said about it. A molecule or a particular mass +of matter could be identified by its form, and is thus in marked +contrast with any portion of ether, for the latter could not be +identified in a similar way. One may therefore say that the ether is +formless. + + +6. MATTER IS GRAVITATIVE. + +The law of gravitation is held as being universal. According to it every +particle of matter in the universe attracts every other particle. The +evidence for this law in the solar system is complete. Sun, planets, +satellites, comets and meteors are all controlled by gravitation, and +the movements of double stars testify to its activity among the more +distant bodies of the universe. The attraction does not depend upon the +kind of matter nor the arrangement of molecules or atoms, but upon the +amount or mass of matter present, and if it be of a definite kind of +matter, as of hydrogen or iron, the gravitative action is proportional +to the number of atoms. + + +THE ETHER IS GRAVITATIONLESS. + +One might infer already that if the ether were structureless, physical +laws operative upon such material substances as atoms could not be +applicable to it, and so indeed all the evidence we have shows that +gravitation is not one of its properties. If it were, and it behaved in +any degree like atomic structures, it would be found to be denser in the +neighbourhood of large bodies like the earth, planets, and the sun. +Light would be turned from its straight path while travelling in such +denser medium, or made to move with less velocity. There is not the +slightest indication of any such effect anywhere within the range of +astronomical vision. + +Gravitation then is a property belonging to matter and not to ether. +The impropriety of thinking or speaking of the ether as matter of any +kind will be apparent if one reflects upon the significance of the law +of gravitation as stated. Every particle of matter in the universe +attracts every other particle. If there be anything else in the universe +which has no such quality, then it should not be called matter, else the +law should read: Some particles of matter attract some other particles, +which would be no law at all, for a real physical law has no exceptions +any more than the multiplication table has. Physical laws are physical +relations, and all such relations are quantitative. + + +7. MATTER IS FRICTIONABLE. + +A bullet shot into the air has its velocity continuously reduced by the +air, to which its energy is imparted by making it move out of its way. A +railway train is brought to rest by the friction brake upon the wheels. +The translatory energy of the train is transformed into the molecular +energy called heat. The steamship requires to propel it fast, a large +amount of coal for its engines, because the water in which it moves +offers great friction--resistance which must be overcome. Whenever one +surface of matter is moved in contact with another surface there is a +resistance called friction, the moving body loses its rate of motion, +and will presently be brought to rest unless energy be continuously +supplied. This is true for masses of matter of all sizes and with all +kinds of motion. Friction is the condition for the transformation of all +kinds of mechanical motions into heat. The test of the amount of +friction is the rate of loss of motion. A top will spin some time in the +air because its point is small. It will spin longer on a plate than on +the carpet, and longer in a vacuum than in the air, for it does not have +the air friction to resist it, and there is no kind or form of matter +not subject to frictional resistance. + + +THE ETHER IS FRICTIONLESS. + +The earth is a mass of matter moving in the ether. In the equatorial +region the velocity of a point is more than a thousand miles in an hour, +for the circumference of the earth is 25,000 miles, and it turns once on +its axis in 24 hours, which is the length of the day. If the earth were +thus spinning in the atmosphere, the latter not being in motion, the +wind would blow with ten times hurricane velocity. The friction would be +so great that nothing but the foundation rocks of the earth's crust +could withstand it, and the velocity of rotation would be reduced +appreciably in a relatively short time. The air moves along with the +earth as a part of it, and consequently no such frictional destruction +takes place, but the earth rotates in the ether with that same rate, and +if the ether offered resistance it would react so as to retard the +rotation and increase the length of the day. Astronomical observations +show that the length of the day has certainly not changed so much as the +tenth of a second during the past 2000 years. The earth also revolves +about the sun, having a speed of about 19 miles in a second, or 68,000 +miles an hour. This motion of the earth and the other planets about the +sun is one of the most stable phenomena we know. The mean distance and +period of revolution of every planet is unalterable in the long run. If +the earth had been retarded by its friction in the ether the length of +the year would have been changed, and astronomers would have discovered +it. They assert that a change in the length of a year by so much as the +hundredth part of a second has not happened during the past thousand +years. This then is testimony, that a velocity of nineteen miles a +second for a thousand years has produced no effect upon the earth's +motion that is noticeable. Nineteen miles a second is not a very swift +astronomical motion, for comets have been known to have a velocity of +400 miles a second when in the neighbourhood of the sun, and yet they +have not seemed to suffer any retardation, for their orbits have not +been shortened. Some years ago a comet was noticed to have its periodic +time shortened an hour or two, and the explanation offered at first was +that the shortening was due to friction in the ether although no other +comet was thus affected. The idea was soon abandoned, and to-day there +is no astronomical evidence that bodies having translatory motion in the +ether meet with any frictional resistance whatever. If a stone could be +thrown in interstellar space with a velocity of fifty feet a second it +would continue to move in a straight line with the same speed for any +assignable time. + +As has been said, light moves with the velocity of 186,000 miles per +second, and it may pursue its course for tens of thousands of years. +There is no evidence that it ever loses either its wave-length or +energy. It is not transformed as friction would transform it, else there +would be some distance at which light of given wave-length and amplitude +would be quite extinguished. The light from distant stars would be +different in character from that coming from nearer stars. Furthermore, +as the whole solar system is drifting in space some 500,000,000 of miles +in a year, new stars would be coming into view in that direction, and +faint stars would be dropping out of sight in the opposite direction--a +phenomenon which has not been observed. Altogether the testimony seems +conclusive that the ether is a frictionless medium, and does not +transform mechanical motion into heat. + + +8. MATTER IS AEOLOTROPIC. + +That is, its properties are not alike in all directions. Chemical +phenomena, crystallization, magnetic and electrical phenomena show each +in their way that the properties of atoms are not alike on opposite +faces. Atoms combine to form molecules, and molecules arrange themselves +in certain definite geometric forms such as cubes, tetrahedra, hexagonal +prisms and stellate forms, with properties emphasized on certain faces +or ends. Thus quartz will twist a ray of light in one direction or the +other, depending upon the arrangement which may be known by the external +form of the crystal. Calc spar will break up a ray of light into two +parts if the light be sent through it in certain directions, but not if +in another. Tourmaline polarizes light sent through its sides and +becomes positively electrified at one end while being heated. Some +substances will conduct sound or light or heat or electricity better in +one direction than in another. All matter is magnetic in some degree, +and that implies polarity. If one will recall the structure of a +vortex-ring, he will see how all the motion is inward on one side and +outward on the other, which gives different properties to the two sides: +a push away from it on one side and a pull toward it on the other. + + +THE ETHER IS ISOTROPIC. + +That is, its properties are alike in every direction. There is no +distinction due to position. A mass of matter will move as freely in one +direction as in another; a ray of light of any wave-length will travel +in it in one direction as freely as in any other; neither velocity nor +direction are changed by the action of the ether alone. + + +9. MATTER IS CHEMICALLY SELECTIVE. + +When the elements combine to form molecules they always combine in +definite ways and in definite proportions. Carbon will combine with +hydrogen, but will drop it if it can get oxygen. Oxygen will combine +with iron or lead or sodium, but cannot be made to combine with +fluorine. No more than two atoms of oxygen can be made to unite with one +carbon atom, nor more than one hydrogen with one chlorine atom. There is +thus an apparent choice for the kind and number of associates in +molecular structure, and the instability of a molecule depends +altogether upon the presence in its neighbourhood of other atoms for +which some of the elements in the molecule have a stronger attraction +or affinity than they have for the atoms they are now combined with. +Thus iron is not stable in the presence of water molecules, and it +becomes iron oxide; iron oxide is not stable in the presence of hot +sulphur, it becomes an iron sulphide. All the elements are thus +selective, and it is by such means that they may be chemically +identified. + +There is no phenomenon in the ether that is comparable with this. +Evidently there could not be unless there were atomic structures having +in some degree different characteristics which we know the ether to be +without. + + +10. THE ELEMENTS OF MATTER ARE HARMONICALLY RELATED. + +It is possible to arrange the elements in the order of their atomic +weights in columns which will show communities of property. Newlands, +Mendeleeff, Meyer, and others have done this. The explanation for such +an arrangement has not yet been forthcoming, but that it expresses a +real fact is certain, for in the original scheme there were several gaps +representing undiscovered elements, the properties of which were +predicted from that of their associates in the table. Some of these have +since been discovered, and their atomic weight and physical properties +accord with those predicted. + +With the ether such a scheme is quite impossible, for the very evident +reason that there are no different things to have relation with each +other. Every part is just like every other part. Where there are no +differences and no distinctions there can be no relations. The ether is +quite harmonic without relations. + + +11. MATTER EMBODIES ENERGY. + +So long as the atoms of matter were regarded as hard round particles, +they were assumed to be inert and only active when acted upon by what +were called forces, which were held to be entities of some sort, +independent of matter. These could pull or push it here or there, but +the matter was itself incapable of independent activity. All this is now +changed, and we are called upon to consider every atom as being itself a +form of energy in the same sense as heat or light are forms of energy, +the energy being embodied in particular forms of motion. Light, for +instance, is a wave motion of the ether. An atom is a rotary ring of +ether. Stop the wave motion, and the light would be annihilated. Stop +the rotation, and the atom would be annihilated for the same reason. As +the ray of light is a particular embodiment of energy, and has no +existence apart from it, so an atom is to be regarded as an embodiment +of energy. On a previous page it is said that energy is the ability of +one body to act upon and move another in some degree. An atom of any +kind is not the inert thing it has been supposed to be, for it can do +something. Even at absolute zero, when all its vibratory or heat energy +would be absent, it would be still an elastic whirling body pulling upon +every other atom in the universe with gravitational energy, twisting +other atoms into conformity with its own position with its magnetic +energy; and, if such ether rings are like the rings which are made in +air, will not stand still in one place even if no others act upon it, +but will start at once by its own inherent energy to move in a right +line at right angles to its own plane and in the direction of the whirl +inside the ring. Two rings of wood or iron might remain in contact with +each other for an indefinite time, but vortex-rings will not, but will +beat each other away as two spinning tops will do if they touch ever so +gently. If they do not thus separate it is because there are other forms +of energy acting to press them together, but such external pressure will +be lessened by the rings' own reactions. + +It is true that in a frictionless medium like the ether one cannot at +present see how such vortex-rings could be produced in it. Certainly not +by any such mechanical methods as are employed to make smoke-rings in +air, for the friction of the air is the condition for producing them. +However they came to be, there is implied the previous existence of the +ether and of energy in some form capable of acting upon it in a manner +radically different from any known in physical science. + +There is good spectroscopic evidence that in some way elements of +different kinds are now being formed in nebulae, for the simplest show +the presence of hydrogen alone. As they increase in complexity other +elements are added, until the spectrum exhibits all the elements we know +of. It has thus seemed likely either that most of what are called +elements are composed of molecular groupings of some fundamental +element, which by proper physical methods might be decomposed, as one +can now decompose a molecule of ammonia or sulphuric acid, or that the +elements are now being created by some extra-physical process in those +far-off regions. In either case an atom is the embodiment of energy in +such a form as to be permanent under ordinary physical circumstances, +but of which, if in any manner it should be destroyed, only the form +would be lost. The ether would remain, and the energy which was embodied +would be distributed in other ways. + + +THE ETHER IS ENDOWED WITH ENERGY. + +The distinction between energy in matter and energy in the ether will be +apparent, on considering that both the ether and energy in some form +must be conceived as existing independent of matter; though every atom +were annihilated, the ether would remain and all the energy embodied in +the atoms would be still in existence in the ether. The atomic energy +would simply be dissolved. One can easily conceive the ether as the same +space-filling, continuous, unlimited medium, without an atom in it. On +this assumption it is clear that no form of energy with which we have to +deal in physical science would have any existence in the ether; for +every one of those forms, gravitational, thermal, electric, magnetic, or +any other--all are the results of the forms of energy in matter. If +there were no atoms, there would be no gravitation, for that is the +attraction of atoms upon each other. If there were no atoms, there could +be no atomic vibration, therefore no heat, and so on for each and all. +Nevertheless, if an atom be the embodiment of energy, there must have +been energy in the ether before any atom existed. One of the properties +of the ether is its ability to distribute energy in certain ways, but +there is no evidence that of itself it ever transforms energy. Once a +given kind of energy is in it, it does not change; hence for the +apparition of a form of energy, like the first vortex-ring, there must +have been not only energy, but some other agency capable of transforming +that energy into a permanent structure. To the best of our knowledge +to-day, the ether would be absolutely helpless. Such energy as was +active in forming atoms must be called by another name than what is +appropriate for such transformations as occur when, for instance, the +mechanical energy of a bullet is transformed into heat when the target +is struck. Behind the ether must be assumed some agency, directing and +controlling energy in a manner totally different from any agency, which +is operative in what we call physical science. Nothing short of what is +called a miracle will do--an event without a physical antecedent in any +way necessarily related to its factors, as is the fact of a stone +related to gravity or heat to an electric current. + +Ether energy is an endowment instead of being an embodiment, and implies +antecedents of a super-physical kind. + + +12. MATTER IS AN ENERGY TRANSFORMER. + +As each different kind of energy represents some specific form of +motion, and _vice versa_, some sort of mechanism is needful for +transforming one kind into another, therefore molecular structure of +one kind or another is essential. The transformation is a mechanical +process, and matter in some particular and appropriate form is the +condition of its taking place. If heat appears, then its antecedent has +been some other form of motion acting upon the substance heated. It may +have been the mechanical motion of another mass of matter, as when a +bullet strikes a target and becomes heated; or it may be friction, as +when a car-axle heats when run without proper oiling to reduce friction; +or it may be condensation, as when tinder is ignited by condensing the +air about it; or chemical reactions, when molecular structure is changed +as in combustion, or an electrical current, which implies a dynamo and +steam-engine or water-power. If light appears, its antecedent has been +impact or friction, condensation or chemical action, and if electricity +appears the same sort of antecedents are present. Whether the one or the +other of these forms of energy is developed, depends upon what kind of a +structure the antecedent energy has acted upon. If radiant energy, +so-called, falls upon a mass of matter, what is absorbed is at once +transformed into heat or into electric or magnetic effects; _which_ one +of these depends upon the character of the mechanism upon which the +radiant energy acts, but the radiant energy itself, which consists of +ether-waves, is traceable back in every case to a mass of matter having +definite characteristic motions. + +One may therefore say with certainty that every physical phenomenon is a +change in the direction, or velocity, or character, of the energy +present, and such change has been produced by matter acting as a +transformer. + + +THE ETHER IS A NON-TRANSFORMER. + +It has already been said that the absence of friction in the ether +enables light-waves to maintain their identity for an indefinite time, +and to an indefinitely great distance. In a uniform, homogeneous +substance of any kind, any kind of energy which might be in it would +continue in it without any change. Uniformity and homogeneity imply +similarity throughout, and the necessary condition for transformation is +unlikeness. One might not look for any kind of physical phenomenon which +was not due to the presence and activity of some heterogeneity. + +As a ray of light continues a ray of light so long as it exists in free +ether, so all kinds of radiations, of whatever wave-length, continue +identical until they fall upon some mechanical structure called matter. +Translatory motion continues translatory, rotary continues rotary, and +vibratory continues to be vibratory, and no transforming change can +take place in the absence of matter. The ether is helpless. + + +13. MATTER IS ELASTIC. + +It is commonly stated that certain substances, like putty and dough, are +inelastic, while some other substances, like glass, steel, and wood, are +elastic. This quality of elasticity, as manifested in such different +degrees, depends upon molecular combinations; some of which, as in glass +and steel, are favourable for exhibiting it, while others mask it, for +the ultimate atoms of all kinds are certainly highly elastic. + +The measure of elasticity in a mass of matter is the velocity with which +a wave-motion will be transmitted through it. Thus the elasticity of the +air determines the velocity of sound in it. If the air be heated, the +elasticity is increased and the sound moves faster. The rates of such +sound-conduction range from a few feet in a second to about 16,000, five +times swifter than a cannon ball. In such elastic bodies as vibrate to +and fro like the prongs of a tuning-fork, or give sounds of a definite +pitch, the rate of vibration is determined by the size and shape of the +body as well as by their elementary composition. The smaller a body is, +the higher its vibratory rate, if it be made of the same material and +the form remains the same. Thus a tuning-fork, that may be carried in +the waistcoat-pocket, may vibrate 500 times a second. If it were only +the fifty-millionth of an inch in size, but of the same material and +form, it would vibrate 30,000,000000 times a second; and if it were made +of ether, instead of steel, it would vibrate as many times faster as the +velocity of waves in the ether is greater than it is in steel, and would +be as many as 400,000000,000000 times per second. The amount of +displacement, or the amplitude of vibration, with the pocket-fork might +be no more than the hundredth of an inch, and this rate measured as +translation velocity would be but five inches per second. If the fork +were of atomic magnitude, and should swing its sides one half the +diameter of the atom, or say the hundred-millionth of an inch, the +translational velocity would be equivalent to about eighty miles a +second, or a hundred and fifty times the velocity of a cannon ball, +which may be reckoned at about 3000 feet. + +That atoms really vibrate at the above rate per second is very certain, +for their vibrations produce ether-waves the length of which may be +accurately measured. When a tuning-fork vibrates 500 times a second, and +the sound travels 1100 feet in the same interval, the length of each +wave will be found by dividing the velocity in the air by the number of +vibrations, or 1100 / 500 = 2.2 feet. In like manner, when one knows +the velocity and wave-length, he may compute the number of vibrations by +dividing the velocity by the wave-length. Now the velocity of the waves +called light is 186,000 miles a second, and a light-wave may be one +forty thousandth of an inch long. The atom that produces the wave must +be vibrating as many times per second as the fifth thousandth of an inch +is contained in 186,000 miles. Reducing this number to inches we have + +186,000 x 5280 x 12 +------------------- = 400,000,000,000,000, nearly. + 1/40,000 + +This shows that the atoms are minute elastic bodies that change their +form rapidly when struck. As rapid as the change is, yet the rate of +movement is only one-fifth that of a comet when near the sun, and is +therefore easily comparable with other velocities observed in masses of +matter. + +These vibratory motions, due to the elasticity of the atoms, is what +constitutes heat. + + +THE ETHER IS ELASTIC. + +The elasticity of a mass of matter is its ability to recover its +original form after that form has been distorted. There is implied that +a stress changes its shape and dimensions, which in turn implies a +limited mass and relative change of position of parts and some degree +of discontinuity. From what has been said of the ether as being +unlimited, continuous, and not made of atoms or molecules, it will be +seen how difficult, if not impossible, it is to conceive how such a +property as elasticity, as manifested in matter, can be attributed to +the ether, which is incapable of deformation, either in structure or +form, the latter being infinitely extended in every direction and +therefore formless. Nevertheless, certain forms of motion, such as +light-waves, move in it with definite velocity, quite independent of how +they originate. This velocity of 186,000 miles a second so much exceeds +any movement of a mass of matter that the motions can hardly be +compared. Thus if 400 miles per second be the swiftest speed of any mass +of matter known--that of a comet near the sun--the ether-wave moves +186,000 / 400 = 465 times faster than such comet, and 900,000 times +faster than sound travels in air. It is clear that if this rate of +motion depends upon elasticity, the elasticity must be of an entirely +different type from that belonging to matter, and cannot be defined in +any such terms as are employed for matter. + +If one considers gravitative phenomena, the difficulty is enormously +increased. The orbit of a planet is never an exact ellipse, +on account of the perturbations produced by the planetary +attractions--perturbations which depend upon the direction and distance +of the attracting bodies. These, however, are so well known that slight +deviations are easily noticed. If gravitative attraction took any such +appreciable time to go from one astronomical body to another as does +light, it would make very considerable differences in the paths of the +planets and the earth. Indeed, if the velocity of gravitation were less +than a million times greater than that of light, its effects would have +been discovered long ago. It is therefore considered that the velocity +of gravitation cannot be less than 186000,000000 miles per second. How +much greater it may be no one can guess. Seeing that gravitation is +ether-pressure, it does not seem probable that its velocity can be +infinite. However that may be, the ability of the ether to transmit +pressure and various disturbances, evidently depends upon properties so +different from those that enable matter to transmit disturbances that +they deserve to be called by different names. To speak of the elasticity +of the ether may serve to express the fact that energy may be +transmitted at a finite rate in it, but it can only mislead one's +thinking if he imagines the process to be similar to energy transmission +in a mass of matter. The two processes are incomparable. No other word +has been suggested, and perhaps it is not needful for most scientific +purposes that another should be adopted, but the inappropriateness of +the one word for the different phenomena has long been felt. + + +14. MATTER HAS DENSITY. + +This quality is exhibited in two ways in matter. In the first, the +different elements in their atomic form have different masses or atomic +weights. An atom of oxygen weighs sixteen times as much as an atom of +hydrogen; that is, it has sixteen times as much matter, as determined by +weight, as the hydrogen atom has, or it takes sixteen times as many +hydrogen atoms to make a pound as it takes of oxygen atoms. This is +generally expressed by saying that oxygen has sixteen times the density +of hydrogen. In like manner, iron has fifty-six times the density, and +gold one hundred and ninety-six. The difference is one in the structure +of the atomic elements. If one imagines them to be vortex-rings, they +may differ in size, thickness, and rate of rotation; either of these +might make all the observed difference between the elements, including +their density. In the second way, density implies compactness of +molecules. Thus if a cubic foot of air be compressed until it occupies +but half a cubic foot, each cubic inch will have twice as many molecules +in it as at first. The amount of air per unit volume will have been +doubled, the weight will have been doubled, the amount of matter as +determined by its weight will have been doubled, and consequently we say +its density has been doubled. + +If a bullet or a piece of iron be hammered, the molecules are compacted +closer together, and a greater number can be got into a cubic inch when +so condensed. In this sense, then, density means the number of molecules +in a unit of space, a cubic inch or cubic centimeter. There is implied +in this latter case that the molecules do not occupy all the available +space, that they may have varying degrees of closeness; in other words, +matter is discontinuous, and therefore there may be degrees in density. + + +THE ETHER HAS DENSITY. + +It is common to have the degree of density of the ether spoken of in the +same way, and for the same reason, that its elasticity is spoken of. The +rate of transmission of a physical disturbance, as of a pressure or a +wave-motion in matter, is conditioned by its degree of density; that is, +the amount of matter per cubic inch as determined by its weight; the +greater the density the slower the rate. So if rate of speed and +elasticity be known, the density may be computed. In this way the +density of the ether has been deduced by noting the velocity of light. +The enormous velocity is supposed to prove that its density is very +small, even when compared with hydrogen. This is stated to be about +equal to that of the air at the height of two hundred and ten miles +above the surface of the earth, where the air molecules are so few that +a molecule might travel for 60,000,000 miles without coming in collision +with another molecule. In air of ordinary density, a molecule can on the +average move no further than about the two-hundred-and-fifty-thousandth +of an inch without such collision. It is plain the density of the ether +is so far removed from the density of anything we can measure, that it +is hardly comparable with such things. If, in addition, one recalls the +fact that the ether is homogeneous, that is all of one kind, and also +that it is not composed of atoms and molecules, then degree of +compactness and number of particles per cubic inch have no meaning, and +the term density, if used, can have no such meaning as it has when +applied to matter. There is no physical conception gained from the study +of matter that can be useful in thinking of it. As with elasticity, so +density is inappropriately applied to the ether, but there is no +substitute yet offered. + + +15. MATTER IS HEATABLE. + +So long as heat was thought to be some kind of an imponderable thing, +which might retain its identity whether it were in or out of matter, +its real nature was obscured by the name given to it. An imponderable +was a mysterious something like a spirit, which was the cause of certain +phenomena in matter. Heat, light, electricity, magnetism, gravitation, +were due to such various agencies, and no one concerned himself with the +nature of one or the other. Bacon thought that heat was a brisk +agitation of the particles of substances, and Count Rumford and Sir +Humphrey Davy thought they proved that it could be nothing else, but +they convinced nobody. Mayer in Germany and Joule in England showed that +quantitative relations existed between work done and heat developed, but +not until the publication of the book called _Heat as a Mode of Motion_, +was there a change of opinion and terminology as to the nature of heat. +For twenty years after that it was common to hear the expressions heat, +and radiant heat, to distinguish between phenomena in matter and what is +now called radiant energy radiations, or simply ether-waves. Not until +the necessity arose for distinguishing between different forms of +energy, and the conditions for developing them, did it become clear to +all that a change in the form of energy implied a change in the form of +motion that embodied it. The energy called heat energy was proved to be +a vibratory motion of molecules, and what happened in the ether as a +result of such vibrations is no longer spoken of as heat, but as ether +waves. When it is remembered that the ultimate atoms are elastic bodies, +and that they will, if free, vibrate in a periodic manner when struck or +shaken in any way, just as a ball will vibrate after it is struck, it is +easy to keep in mind the distinction between the mechanical form of +motion spent in striking and the vibratory form of the motion produced +by it. The latter is called heat; no other form of motion than that is +properly called heat. It is this alone that represents temperature, the +rate and amplitude of such atomic and molecular vibrations as constitute +change, of form. Where molecules like those in a gas have some freedom +of movement between impacts, they bound away from each other with +varying velocities. The path of such motion may be long or short, +depending upon the density or compactness of the molecules, but such +changes in position are not heat for a molecule any more than the flight +of a musket ball is heat, though it may be transformed into heat on +striking the target. + +This conception of heat as the rapid change in the form of atoms and +molecules, due to their elasticity, is a phenomenon peculiar to matter. +It implies a body possessing form that may be changed; elasticity, that +its changes may be periodic, and degrees of freedom that secure space +for the changes. Such a body may be heated. Its temperature will depend +upon the amplitude of such vibrations, and will be limited by the +maximum amplitude. + + +THE ETHER IS UNHEATABLE. + +The translatory motion of a mass of matter, big or little, through the +ether, is not arrested in any degree so far as observed, but the +internal vibratory motion sets up waves in the ether, the ether absorbs +the energy, and the amplitude is continually lessened. The motion has +been transferred and transformed; transferred from matter to the ether, +and transformed from vibratory to waves travelling at the rate of +186,000 miles per second. The latter is not heat, but the result of +heat. With the ether constituted as described, such vibratory motion as +constitutes heat is impossible to it, and hence the characteristic of +heat-motion in it is impossible; it cannot therefore be heated. The +space between the earth and the sun may have any assignable amount of +energy in the form of ether waves or light, but not any temperature. One +might loosely say that the temperature of empty spaces was absolute +zero, but that would not be quite correct, for the idea of temperature +cannot properly be entertained as applicable to the ether. To say that +its temperature was absolute zero, would serve to imply that it might be +higher, which is inadmissible. + +When energy has been transformed, the old name by which the energy was +called must be dropped. Ether cannot be heated. + + +16. MATTER IS INDESTRUCTIBLE. + +This is commonly said to be one of the essential properties of matter. +All that is meant by it, however, is simply this: In no physical or +chemical process to which it has been experimentally subjected has there +been any apparent loss. The matter experimented upon may change from a +solid or liquid to a gas, or the molecular change called chemical may +result in new compounds, but the weight of the material and its atomic +constituents have not appreciably changed. That matter cannot be +annihilated is only the converse of the proposition that matter cannot +be created, which ought always to be modified by adding, by physical or +chemical processes at present known. A chemist may work with a few +grains of a substance in a beaker, or test-tube, or crucible, and after +several solutions, precipitations, fusions and dryings, may find by +final weighing that he has not lost any appreciable amount, but how much +is an appreciable amount? A fragment of matter the ten-thousandth of an +inch in diameter has too small a weight to be noted in any balance, yet +it would be made up of thousands of millions of atoms. Hence if, in the +processes to which the substance had been subjected, there had been the +total annihilation of thousands of millions of atoms, such phenomenon +would not have been discovered by weighing. Neither would it have been +discovered if there had been a similar creation or development of new +matter. All that can be asserted concerning such events is, that they +have not been discovered with our means of observation. + +The alchemists sought to transform one element into another, as lead +into gold. They did not succeed. It was at length thought to be +impossible, and the attempt to do it an absurdity. Lately, however, +telescopic observation of what is going on in nebulae, which has already +been referred to, has somewhat modified ideas of what is possible and +impossible in that direction. It is certainly possible roughly to +conceive how such a structure as a vortex-ring in the ether might be +formed. With certain polarizing apparatus it is possible to produce rays +of circularly polarized light. These are rays in which the motion is an +advancing rotation like the wire in a spiral spring. If such a line of +rotations in the ether were flexible, and the two ends should come +together, there is reason for thinking they would weld together, in +which case the structure would become a vortex-ring and be as durable as +any other. There is reason for believing, also, that somewhat similar +movements are always present in a magnetic field, and though we do not +know how to make them close up in the proper way, it does not follow +that it is impossible for them to do so. + +The bearing of all this upon the problem of the transmutation of +elements is evident. No one now will venture to deny its possibility as +strongly as it was denied a generation ago. It will also lead one to be +less confident in the theory that matter is indestructible. Assuming the +vortex-ring theory of atoms to be true, if in any way such a ring could +be cut or broken, there would not remain two or more fragments of a ring +or atom. The whole would at once be dissolved into the ether. The ring +and rotary energy that made it an atom would be destroyed, but not the +substance it was made of, nor the energy which was embodied therein. For +a long time philosophers have argued, and commonsense has agreed with +them, that an atom which could not be ideally broken into two parts was +impossible, that one could at any rate think of half an atom as a real +objective possibility. This vortex-ring theory shows easily how possible +it is to-day to think what once was philosophically incredible. It shows +that metaphysical reasoning may be ever so clear and apparently +irrefragable, yet for all that it may be very unsound. The trouble does +not come so much from the logic as from the assumption upon which the +logic is founded. In this particular case the assumption was that the +ultimate particles of matter were hard, irrefragable somethings, without +necessary relations to anything else, or to energy, and irrefragable +only because no means had been found of breaking them. + +The destructibility or indestructibility of the ether cannot be +considered from the same standpoint as that for matter, either ideally +or really. Not ideally, because we are utterly without any mechanical +conceptions of the substance upon which one can base either reason or +analogy; and not really, because we have no experimental evidence as to +its nature or mode of operation. If it be continuous, there are no +interspaces, and if it be illimitable there is no unfilled space +anywhere. Furthermore, one might infer that if in any way a portion of +the ether could be annihilated, what was left would at once fill up the +vacated space, so there would be no record left of what had happened. +Apparently, its destruction would be the destruction of a substance, +which is a very different thing from the destruction of a mode of +motion. In the latter, only the form of the motion need be destroyed to +completely obliterate every trace of the atom. In the former, there +would need to be the destruction of both substance and energy, for it is +certain, for reasons yet to be attended to, that the ether is saturated +with energy. + +One may, without mechanical difficulties, imagine a vortex-ring +destroyed. It is quite different with the ether itself, for if it were +destroyed in the same sense as the atom of matter, it would be changed +into something else which is not ether, a proposition which assumes the +existence of another entity, the existence for which is needed only as a +mechanical antecedent for the other. The same assumption would be needed +for this entity as for the ether, namely, something out of which it was +made, and this process of assuming antecedents would be interminable. +The last one considered would have the same difficulties to meet as the +ether has now. The assumption that it was in some way and at some time +created is more rational, and therefore more probable, than that it +either created itself or that it always existed. Considered as the +underlying stratum of matter, it is clear that changes of any kind in +matter can in no way affect the quantity of ether. + + +17. MATTER HAS INERTIA. + +The resistance that a mass of matter opposes to a change in its position +or rate and direction of movement, is called inertia. That it should +actively oppose anything has been already pointed out as reason for +denying that matter is inert, but inertia is the measure of the reaction +of a body when it is acted upon by pressure from any source tending to +disturb its condition of either rest or motion. It is the equivalent of +mass, or the amount of matter as measured by gravity, and is a fixed +quantity; for inertia is as inherent as any other quality, and belongs +to the ultimate atoms and every combination of them. It implies the +ability to absorb energy, for it requires as much energy to bring a +moving body to a standstill as was required to give it its forward +motion. + +Both rotary and vibratory movements are opposed by the same property. A +grindstone, a tuning-fork, and an atom of hydrogen require, to move them +in their appropriate ways, an amount of energy proportionate to their +mass or inertia, which energy is again transformed through friction into +heat and radiated away. + +One may say that inertia is the measure of the ability of a body to +transfer or transform mechanical energy. The meteorite that falls upon +the earth to-day gives, on its impact, the same amount of energy it +would have given if it had struck the earth ten thousand years ago. The +inertia of the meteor has persisted, not as energy, but as a factor of +energy. We commonly express the energy of a mass of matter by +_mv_^{2}/2, where _m_ stands for the mass and _v_ for its velocity. We +might as well, if it were as convenient, substitute inertia for mass, +and write the expression _iv_^{2}/2, for the mass, being measured by its +inertia, is only the more common and less definitive word for the same +thing. The energy of a mass of matter is, then, proportional to its +inertia, because inertia is one of its factors. Energy has often been +treated as if it were an objective thing, an entity and a unity; but +such a conception is evidently wrong, for, as has been said before, it +is a product of two factors, either of which may be changed in any +degree if the other be changed inversely in the same degree. A cannon +ball weighing 1000 pounds, and moving 100 feet per second, will have +156,000 foot-pounds of energy, but a musket ball weighing an ounce will +have the same amount when its velocity is 12,600 feet per second. +Nevertheless, another body acting upon either bullet or cannon ball, +tending to move either in some new direction, will be as efficient +while those bodies are moving at any assignable rate as when they are +quiescent, for the change in direction will depend upon the inertia of +the bodies, and that is constant. + +The common theory of an inert body is one that is wholly passive, having +no power of itself to move or do anything, except as some agency outside +itself compels it to move in one way or another, and thus endows it with +energy. Thus a stone or an iron nail are thought to be inert bodies in +that sense, and it is true that either of them will remain still in one +place for an indefinite time and move from it only when some external +agency gives them impulse and direction. Still it is known that such +bodies will roll down hill if they will not roll up, and each of them +has itself as much to do with the down-hill movement as the earth has; +that is, it attracts the earth as much as the earth attracts it. If one +could magnify the structure of a body until the molecules became +individually visible, every one of them would be seen to be in intense +activity, changing its form and relative position an enormous number of +times per second in undirected ways. No two such molecules move in the +same way at the same time, and as all the molecules cohere together, +their motions in different directions balance each other, so that the +body as a whole does not change its position, not because there is no +moving agency in itself, but because the individual movements are +scattering, and not in a common direction. An army may remain in one +place for a long time. To one at a distance it is quiescent, inert. To +one in the camp there is abundant sign of activity, but the movements +are individual movements, some in one direction and some in another, and +often changing. The same army on the march has the same energy, the same +rate of individual movement; but all have a common direction, it moves +as a whole body into new territory. So with the molecules of matter. In +large masses they appear to be inert, and to do nothing, and to be +capable of doing nothing. That is only due to the fact that their energy +is undirected, not that they can do nothing. The inference that if +quiescent bodies do not act in particular ways they are inert, and +cannot act in any kind of a way, is a wrong inference. An illustration +may perhaps make this point plainer. A lump of coal will be still as +long as anything if it be undisturbed. Indeed, it has thus lain in a +coal-bed for millions of years probably, but if coal be placed where it +can combine with oxygen, it forthwith does so, and during the process +yields a large amount of energy in the shape of heat. One pound of coal +in this way gives out 14,000 heat units, which is the equivalent of +11,000,000 foot-pounds of work, and if it could be all utilized would +furnish a horse-power for five and a half hours. Can any inert body +weighing a pound furnish a horse-power for half a day? And can a body +give out what it has not got? Are gunpowder and nitro-glycerine inert? +Are bread and butter and foods in general inert because they will not +push and pull as a man or a horse may? All have energy, which is +available in certain ways and not in others, and whatever possesses +energy available in any way is not an ideally inert body. Lastly, how +many inert bodies together will it take to make an active body? If the +question be absurd, then all the phenomena witnessed in bodies, large or +small, are due to the fact that the atoms are not inert, but are +immensely energetic, and their inertia is the measure of their rates of +exchanging energy. + + +THE ETHER IS CONDITIONALLY POSSESSED OF INERTIA. + +A moving mass of matter is brought to rest by friction, because it +imparts its motion at some rate to the body it is in contact with. +Generally the energy is transformed into heat, but sometimes it appears +as electrification. Friction is only possible because one or both of the +bodies possess inertia. That a body may move in the ether for an +indefinite time without losing its velocity has been stated as a reason +for believing the ether to be frictionless. If it be frictionless, then +it is without inertia, else the energy of the earth and of a ray of +light would be frittered away. A ray of light can only be transformed +when it falls upon molecules which may be heated by it. As the ether +cannot be heated and cannot transform translational energy, it is +without inertia for _such_ a form of motion and its embodied energy. + +It is not thus with other forms of energy than the translational. Atomic +and molecular vibrations are so related to the ether that they are +transformed into waves, which are conducted away at a definite rate. +This shows that such property of inertia as is possessed by the ether is +selective and not like that of matter, which is equally "inertiative" +under all conditions. Similarly with electric and magnetic phenomena, it +is capable of transforming the energy which may reside as stress in the +ether, and other bodies moving in the space so affected meet with +frictional resistance, for they become heated if the motion be +maintained. On the other hand, there is no evidence that the body which +produced the electric or magnetic stress suffers any degree of friction +on moving in precisely the same space. A bar magnet rotating on its +longitudinal axis does not disturb its own field, but a piece of iron +revolving near the magnet will not only become heated, but will heat the +stationary magnet. Much experimental work has been done to discover, if +possible, the relation of a magnet to its ether field. As the latter is +not disturbed by the rotation of the magnet, it has been concluded that +the field does not rotate; but as every molecule in the magnet has its +own field independent of all the rest, it is mechanically probable that +each such field does vary in the rotation, but among the thousands of +millions of such fields the average strength of the field does not vary +within measurable limits. Another consideration is that the magnetic +field itself, when moved in space, suffers no frictional resistance. +There is no magnetic energy wasted through ether inertia. These +phenomena show that whether the ether exhibits the quality called +inertia depends upon the kind of motion it has. + + +18. MATTER IS MAGNETIC. + +The ordinary phenomenon of magnetism is shown by bringing a piece of +iron into the neighbourhood of a so-called magnet, where it is attracted +by the latter, and if free to move will go to and cling to the magnet. A +delicately suspended magnetic needle will be affected appreciably by a +strong magnet at the distance of several hundred feet. As the strength +of such action varies inversely as the square of the distance from the +magnet, it is evident there can be no absolute boundary to it. At a +distance from an ordinary magnet it becomes too weak to be detected by +our methods, not that there is a limit to it. It is customary to think +of iron as being peculiarly endowed with magnetic quality, but all kinds +of matter possess it in some degree. Wood, stone, paper, oats, sulphur, +and all the rest, are attracted by a magnet, and will stick to it if the +magnet be a strong one. Whether a piece of iron itself exhibits the +property depends upon its temperature, for near 700 degrees it becomes +as magnetically indifferent as a piece of copper at ordinary +temperature. Oxygen, too, at 200 degrees below the zero of Centigrade +adheres to a magnet like iron. + +In this as in so many other particulars, how a piece of matter behaves +depends upon its temperature, not that the essential qualities are +modified in any degree, but temperature interferes with atomic +arrangement and aggregation, and so disguises their phenomena. + +As every kind of matter is thus affected by a magnet, the manifestations +differing but in degree, it follows that all kinds of atoms--all the +elements--are magnetic. An inherent property in them, as much so as +gravitation or inertia; apparently a quality depending upon the +structure of the atoms themselves, in the same sense as gravitation is +thus dependent, as it is not a quality of the ether. + +An atom must, then, be thought of as having polarity, different +qualities on the two sides, and possessing a magnetic field as extensive +as space itself. The magnetic field is the stress or pressure in the +ether produced by the magnetic body. This ether pressure produced by a +magnet may be as great as a ton per square inch. It is this pressure +that holds an armature to the magnet. As heat is a molecular condition +of vibration, and radiant energy the result of it, so is magnetism a +property of molecules, and the magnetic field the temporary condition in +the ether, which depends upon the presence of a magnetic body. We no +longer speak of the wave-motion in the ether which results from heat, as +heat, but call it radiation, or ether waves, and for a like reason the +magnetic field ought not to be called magnetism. + + +THE ETHER IS NON-MAGNETIC. + +A magnetic field manifests itself in a way that implies that the ether +structure, if it may be said to have any, is deformed--deformed in such +a sense that another magnet in it tends to set itself in the plane of +the stress; that is, the magnet is twisted into a new position to +accommodate itself to the condition of the medium about it. The new +position is the result of the reaction of the ether upon the magnet and +ether pressure acting at right angles to the body that produced the +stress. Such an action is so anomalous as to suggest the propriety of +modifying the so-called third law of motion, viz., action and reaction +are equal and opposite, adding that sometimes action and reaction are at +right angles. + +There is no condition or property exhibited by the ether itself which +shows it to have any such characteristic as attraction, repulsion, or +differences in stress, except where its condition is modified by the +activities of matter in some way. The ether itself is not attracted or +repelled by a magnet; that is, it is not a magnetic body in any such +sense as matter in any of its forms is, and therefore cannot properly be +called magnetic. + +It has been a mechanical puzzle to understand how the vibratory motions +called heat could set up light waves in the ether seeing that there is +an absence of friction in the latter. In the endeavour to conceive it, +the origin of sound-waves has been in mind, where longitudinal air-waves +are produced by the vibrations of a sounding body, and molecular impact +is the antecedent of the waves. The analogy does not apply. The +following exposition may be helpful in grasping the idea of such +transformation and change of energy from matter to the ether. + +Consider a straight bar permanent magnet to be held in the hand. It has +its north and south poles and its field, the latter extending in every +direction to an indefinite distance. The field is to be considered as +ether stress of such a sort as to tend to set other magnets in it in new +positions. If at a distance of ten feet there were a delicately-poised +magnet needle, every change in the position of the magnet held in the +hand would bring about a change in the position of the needle. If the +position of the hand magnet were completely reversed, so the south pole +faced where the north pole faced before, the field would have been +completely reversed, and the poised needle would have been pushed by the +field into an opposite position. If the needle were a hundred feet away, +the change would have been the same except in amount. The same might be +said if the two were a mile apart, or the distance of the moon or any +other distance, for there is no limit to an ether magnetic field. +Suppose the hand magnet to have its direction completely reversed once +in a second. The whole field, and the direction of the stress, would +necessarily be reversed as often. But this kind of change in stress is +known by experiment to travel with the speed of light, 186,000 miles a +second; the disturbance due to the change of position of the magnet will +therefore be felt in some degree throughout space. In a second and a +third of a second it will have reached the moon, and a magnet there will +be in some measure affected by it. If there were an observer there with +a delicate-enough magnet, he could be witness to its changes once a +second for the same reason one in the room could. The only difference +would be one of amount of swing. It is therefore theoretically possible +to signal to the moon with a swinging magnet. Suppose again that the +magnet should be swung twice a second, there would be formed two waves, +each one half as long as the first. If it should swing ten times a +second, then the waves would be one-tenth of 186,000 miles long. If in +some mechanical way it could be rotated 186,000 times a second, the wave +would be but one mile long. Artificial ways have been invented for +changing this magnet field as many as 100 million times a second, and +the corresponding wave is less than a foot long. The shape of a magnet +does not necessarily make it weaker or stronger as a magnet, but if the +poles are near together the magnetic field is denser between them than +when they are separated. The ether stress is differently distributed for +every change in the relative positions of the poles. + +A common U-magnet, if struck, will vibrate like a tuning-fork, and gives +out a definite pitch. Its poles swing towards and away from each other +at uniform rates, and the pitch of the magnet will depend upon its size, +thickness, and the material it is made of. + +Let ten or fifteen ohms of any convenient-sized wire be wound upon the +bend of a commercial U-magnet. Let this wire be connected to a telephone +in its circuit. When the magnet is made to sound like a tuning-fork, the +pitch will be reproduced in the telephone very loudly. If another magnet +with a different pitch be allowed to vibrate near the former, the pitch +of the vibrating body will be heard in the telephone, and these show +that the changing magnetic field reacts upon the quiescent magnet, and +compels the latter to vibrate at the same rate. The action is an ether +action, the waves are ether waves, but they are relatively very long. If +the magnet makes 500 vibrations a second, the waves will be 372 miles +long, the number of times 500 is contained in 186,000 miles. Imagine the +magnet to become smaller and smaller until it was the size of an atom, +the one-fifty-millionth of an inch. Its vibratory rate would be +proportionally increased, and changes in its form will still bring about +changes in its magnetic field. But its magnetic field is practically +limitless, and the number of vibrations per second is to be reckoned +as millions of millions; the waves are correspondingly short, +small fractions of an inch. When they are as short as the +one-thirty-seven-thousandth of an inch, they are capable of affecting +the retina of the eye, and then are said to be visible as red light. If +the vibratory rate be still higher, and the corresponding waves be no +more than one-sixty-thousandth of an inch long, they affect the retina +as violet light, and between these limits there are all the waves that +produce a complete spectrum. The atoms, then, shake the ether in this +way because they all have a magnetic hold upon the ether, so that any +disturbance of their own magnetism, such as necessarily comes when they +collide, reacts upon the ether for the same reason that a large magnet +acts thus upon it when its poles approach and recede from each other. It +is not a phenomenon of mechanical impact or frictional resistance, since +neither are possible in the ether. + + +19. MATTER EXISTS IN SEVERAL STATES. + +Molecular cohesion exists between very wide ranges. When strong, so if +one part of a body is moved the whole is moved in the same way, without +breaking continuity or the relative positions of the molecules, we call +the body a solid. In a liquid, cohesion is greatly reduced, and any part +of it may be deformed without materially changing the form of the rest. +The molecules are free to move about each other, and there is no +definite position which any need assume or keep. With gases, the +molecules are without any cohesion, each one is independent of every +other one, collides with and bounds away from others as free elastic +particles do. Between impacts it moves in what is called its free path, +which may be long or short as the density of the gas be less or greater. + +These differing degrees of cohesion depend upon temperature, for if the +densest and hardest substances are sufficiently heated they will become +gaseous. This is only another way of saying that the states of matter +depend upon the amount of molecular energy present. Solid ice becomes +water by the application of heat. More heat reduces it to steam; still +more decomposes the steam molecules into oxygen and hydrogen molecules; +and lastly, still more heat will decompose these molecules into their +atomic state, complete dissociation. On cooling, the process of +reduction will be reversed until ice has been formed again. + +Cohesive strength in solids is increased by reduction of temperature, +and metallic rods become stronger the colder they are. + +No distinction is now made between cohesion and chemical affinity, and +yet at low temperatures chemical action will not take place, which +phenomenon shows there is a distinction between molecular cohesion and +molecular structure. In molecular structure, as determined by chemical +activity, the molecules and atoms are arranged in definite ways which +depend upon the rate of vibrations of the components. The atoms are set +in definite positions to constitute a given molecule. But atoms or +molecules may cohere for other reasons, gravitative or magnetic, and +relative positions would be immaterial. In the absence of temperature, a +solid body would be solider and stronger than ever, while a gaseous mass +would probably fall by gravity to the floor of the containing vessel +like so much dust. The molecular structure might not be changed, for +there would be no agency to act upon it in a disturbing way. + + +THE ETHER HAS NO CORRESPONDING STATES. + +Degrees of density have already been excluded, and the homogeneity and +continuity of the ether would also exclude the possibility of different +states at all comparable with such as belong to matter. As for cohesion, +it is doubtful if the term ought to be applied to such a substance. The +word itself seems to imply possible separateness, and if the ether be a +single indivisible substance, its cohesion must be infinite and is +therefore not a matter of degree. The ether has sometimes been +considered as an elastic solid, but such solidity is comparable with +nothing we call solid in matter, and the word has to be defined in a +special sense in order that its use may be tolerated at all. In addition +to this, some of the phenomena exhibited by it, such as diffraction and +double refraction, are quite incompatible with the theory that the ether +is an elastic solid. The reasons why it cannot be considered as a liquid +or gas have been considered previously. + +The expression _states of matter_ cannot be applied to the ether in any +such sense as it is applied to matter, but there is one sense when +possibly it may be considered applicable. Let it be granted that an atom +is a vortex-ring of ether in the ether, then the state of being in ring +rotation would suffice to differentiate that part of the ether from the +rest, and give to it a degree of individuality not possessed by the +rest; and such an atom might be called a state of ether. In like manner, +if other forms of motion, such as transverse waves, circular and +elliptical spirals, or others, exist in the ether, then such movements +give special character to the part thus active, and it would be proper +to speak of such states of the ether, but even thus the word would not +be used in the same sense as it is used when one speaks of the states of +matter as being solid, liquid, and gaseous. + + +20. SOLID MATTER CAN EXPERIENCE A SHEARING STRESS, LIQUIDS AND GASES +CANNOT. + +A sliding stress applied to a solid deforms it to a degree which depends +upon the stress and the degree of rigidity preserved by the body. Thus +if the hand be placed upon a closed book lying on the table, and +pressure be so applied as to move the upper side of the book but not the +lower, the book is said to be subject to a shearing stress. If the +pressing hand has a twisting motion, the book will be warped. Any solid +may be thus sheared or warped, but neither liquids nor gases can be so +affected. Molecular cohesion makes it possible in the one, and the lack +of it, impossible in the others. The solid can maintain such a +deformation indefinitely long, if the pressure does not rupture its +molecular structure. + + +THE ETHER CAN MAINTAIN A SHEARING STRESS. + +The phenomena in a magnetic field show that the stress is of such a sort +as to twist into a new directional position the body upon which it acts +as exhibited by a magnetic needle, also as indicated by the transverse +vibrations of the ether waves, and again by the twist given to plane +polarized light when moving through a magnetic field. These are all +interpreted as indicative of the direction of ether stress, as being +similar to a shearing stress in solid matter. The fact has been adduced +to show the ether to be a solid, but such a phenomenon is certainly +incompatible with a liquid or gaseous ether. This kind of stress is +maintained indefinitely about a permanent magnet, and the mechanical +pressure which may result from it is a measure of the strength of the +magnetic field, and may exceed a thousand pounds per square inch. + + +21. OTHER PROPERTIES OF MATTER. + +There are many secondary qualities exhibited by matter in some of its +forms, such as hardness, brittleness, malleability, colour, etc., and +the same ultimate element may exhibit itself in the most diverse ways, +as is the case with carbon, which exists as lamp-black, charcoal, +graphite, jet, anthracite and diamond, ranging from the softest to the +hardest of known bodies. Then it may be black or colourless. Gold is +yellow, copper red, silver white, chlorine green, iodine purple. The +only significance any or all of such qualities have for us here is that +the ether exhibits none of them. There is neither hardness nor +brittleness, nor colour, nor any approach to any of the characteristics +for the identification of elementary matter. + + +22. SENSATION DEPENDS UPON MATTER. + +However great the mystery of the relation of body to mind, it is quite +true that the nervous system is the mechanism by and through which all +sensation comes, and that in our experience in the absence of nerves +there is neither sensation nor consciousness. The nerves themselves are +but complex chemical structures; their molecular constitution is said to +embrace as many as 20,000 atoms, chiefly carbon, hydrogen, oxygen, and +nitrogen. There must be continuity of this structure too, for to sever a +nerve is to paralyze all beyond. If all knowledge comes through +experience, and all experience comes through the nervous system, the +possibilities depend upon the mechanism each one is provided with for +absorbing from his environment, what energies there are that can act +upon the nerves. Touch, taste, and smell imply contact, sound has +greater range, and sight has the immensity of the universe for its +field. The most distant but visible star acts through the optic nerve to +present itself to consciousness. It is not the ego that looks out +through the eyes, but it is the universe that pours in upon the ego. + +Again, all the known agencies that act upon the nerves, whether for +touch or sound or sight, imply matter in some of its forms and +activities, to adapt the energy to the nervous system. The mechanism +for the perception of light is complicated. The light acts upon a +sensitive surface where molecular structure is broken up, and this +disturbance is in the presence of nerve terminals, and the sensation is +not in the eye but in the sensorium. In like manner for all the rest; so +one may fairly say that matter is the condition for sensation, and in +its absence there would be nothing we call sensation. + + +THE ETHER IS INSENSIBLE TO NERVES. + +The ether is in great contrast with matter in this particular. There is +no evidence that in any direct way it acts upon any part of the nervous +system, or upon the mind. It is probable that this lack of relation +between the ether and the nervous system was the chief reason why its +discovery was so long delayed, as the mechanical necessities for it even +now are felt only by such as recognize continuity as a condition for the +transmission of energy of whatever kind it may be. Action at a distance +contradicts all experience, is philosophically incredible, and is +repudiated by every one who once perceives that energy has two +factors--substance and motion. + +The table given below presents a list of twenty-two of the known +properties of matter contrasted with those exhibited by the ether. In +none of them are the properties of the two identical, and in most of +them what is true for one is not true for the other. They are not simply +different, they are incomparable. + +From the necessities of the case, as knowledge has been acquired and +terminology became essential for making distinctions, the ether has been +described in terms applicable to matter, hence such terms as mass, +solidity, elasticity, density, rigidity, etc., which have a definite +meaning and convey definite mechanical conceptions when applied to +matter, but have no corresponding meaning and convey no such mechanical +conceptions when applied to the ether. It is certain that they are +inappropriate, and that the ether and its properties cannot be described +in terms applicable to matter. Mathematical considerations derived from +the study of matter have no advantage, and are not likely to lead us to +a knowledge of the ether. + +Only a few have perceived the inconsistency of thinking of the two in +the same terms. In his _Grammar of Science_, Prof. Karl Pearson says, +"We find that our sense-impressions of hardness, weight, colour, +temperature, cohesion, and chemical constitution, may all be described +by the aid of the motions of a single medium, which itself is conceived +to have no hardness, weight, colour, temperature, nor indeed elasticity +of the ordinary conceptual type." + +None of the properties of the ether are such as one would or could have +predicted if he had had all the knowledge possessed by mankind. Every +phenomenon in it is a surprise to us, because it does not follow the +laws which experience has enabled us to formulate for matter. A +substance which has none of the phenomenal properties of matter, and is +not subject to the known laws of matter, ought not to be called matter. +Ether phenomena and matter phenomena belong to different categories, and +the ends of science will not be conserved by confusing them, as is done +when the same terminology is employed for both. + +There are other properties belonging to the ether more wonderful, if +possible, than those already mentioned. Its ability to maintain enormous +stresses of various kinds without the slightest evidence of +interference. There is the gravitational stress, a direct pull between +two masses of matter. Between two molecules it is immeasurably small +even when close together, but the prodigious number of them in a bullet +brings the action into the field of observation, while between such +bodies as the earth and moon or sun, the quantity reaches an astonishing +figure. Thus if the gravitative tension due to the gravitative +attraction of the earth and moon were to be replaced by steel wires +connecting the two bodies to prevent the moon from leaving its orbit, +there would be needed four number ten steel wires to every square inch +upon the earth, and these would be strained nearly to the breaking +point. Yet this stress is not only endured continually by this pliant, +impalpable, transparent medium, but other bodies can move through the +same space apparently as freely as if it were entirely free. In addition +to this, the stress from the sun and the more variable stresses from the +planets are all endured by the same medium in the same space and +apparently a thousand or a million times more would not make the +slightest difference. Rupture is impossible. + +Electric and magnetic stresses, acting parallel or at right angles to +the other, exist in the same space and to indefinite degrees, neither +modifying the direction nor amount of either of the others. + +These various stresses have been computed to represent energy, which if +it could be utilized, each cubic inch of space would yield five hundred +horse-power. It shows what a store-house of energy the ether is. If +every particle of matter were to be instantly annihilated, the universe +of ether would still have an inexpressible amount of energy left. To +draw at will directly from this inexhaustible supply, and utilize it for +the needs of mankind, is not a forlorn hope. + +The accompanying table presents these contrasting properties for +convenient inspection. + + +CONTRASTED PROPERTIES OF MATTER AND THE ETHER. + + MATTER. ETHER. + + 1. Discontinuous Continuous + 2. Limited Unlimited + 3. Heterogeneous Homogeneous + 4. Atomic Non-atomic + 5. Definite structure Structureless + 6. Gravitative Gravitationless + 7. Frictionable Frictionless + 8. AEolotropic Isotropic + 9. Chemically selective ---- +10. Harmonically related ---- +11. Energy embodied Energy endowed +12. Energy transformer Non-transformer +13. Elastic Elastic? +14. Density Density? +15. Heatable Unheatable +16. Indestructible? Indestructible +17. Inertiative Inertiative conditionally +18. Magnetic ---- +19. Variable states ---- +20. Subject to shearing stress + in solid Shearing stress maintained +21. Has Secondary qualities ---- +22. Sensation depends upon Insensible to nerves + + + + +CHAPTER III + +Antecedents of Electricity--Nature of what is + transformed--Series of transformations for the + production of light--Positive and negative + Electricity--Positive and negative twists--Rotations + about a wire--Rotation of an arc--Ether a + non-conductor--Electro-magnetic waves--Induction + and inductive action--Ether stress and atomic + position--Nature of an electric current--Electricity + a condition, not an entity. + + +So far as we have knowledge to-day, the only factors we have to consider +in explaining physical phenomena are: (1) Ordinary matter, such as +constitutes the substance of the earth, and the heavenly bodies; (2) the +ether, which is omnipresent; and (3) the various forms of motion, which +are mutually transformable in matter, and some of which, but not all, +are transformable into ether forms. For instance, the translatory motion +of a mass of matter can be imparted to another mass by simple impact, +but translatory motion cannot be imparted to the ether, and, for that +reason, a body moving in it is not subject to friction, and continues +to move on with velocity undiminished for an indefinite time; but the +vibratory motion which constitutes heat is transformable into +wave-motion in the ether, and is transmitted away with the speed of +light. The kind of motion which is thus transformed is not even a +to-and-fro swing of an atom, or molecule, like the swing of a pendulum +bob, but that due to a change of form of the atoms within the molecule, +otherwise there could be no such thing as spectrum analysis. Vibratory +motion of the matter becomes undulatory motion in the ether. The +vibratory motion we call heat; the wave-motion we call sometimes radiant +energy, sometimes light. Neither of these terms is a good one, but we +now have no others. + +It is conceded that it is not proper to speak of the wave-motion in the +ether as _heat_; it is also admitted that the ether is not heated by the +presence of the wave--or, in other words, the temperature of the ether +is absolute zero. Matter only can be heated. But the ether waves can +heat other matter they may fall on; so there are three steps in the +process and two transformations--(1) vibrating matter; (2) waves in the +ether; (3) vibration in other matter. Energy has been transferred +indirectly. What is important to bear in mind is, that when a form of +energy in matter is transformed in any manner so as to lose its +characteristics, it is not proper to call it by the same name after as +before, and this we do in all cases when the transformation is from one +kind in matter to another kind in matter. Thus, when a bullet is shot +against a target, before it strikes it has what we call mechanical +energy, and we measure that in foot-pounds; after it has struck the +target, the transformation is into heat, and this has its mechanical +equivalent, but is not called mechanical energy, nor are the motions +which embody it similar. The mechanical ideas in these phenomena are +easy to grasp. They apply to the phenomena of the mechanics of large and +small bodies, to sound, to heat, and to light, as ordinarily considered, +but they have not been applied to electric phenomena, as they evidently +should be, unless it be held that such phenomena are not related to +ordinary phenomena, as the latter are to one another. + +When we would give a complete explanation of the phenomena exhibited by, +say, a heated body, we need to inquire as to the antecedents of the +manifestation, and also its consequents. Where and how did it get its +heat? Where and how did it lose it? When we know every step of those +processes, we know all there is to learn about them. Let us undertake +the same thing for some electrical phenomena. + +First, under what circumstances do electrical phenomena arise? + +(1) _Mechanical_, as when two different kinds of matter are subject to +friction. + +(2) _Thermal_, as when two substances in molecular contact are heated at +the junction. + +(3) _Magnetic_, as when any conductor is in a changing magnetic field. + +(4) _Chemical_, as when a metal is being dissolved in any solution. + +(5) _Physiological_, as when a muscle contracts. + +[Illustration: FIG. 5.--Frictional electrical machine.] + +Each of these has several varieties, and changes may be rung on +combinations of them, as when mechanical and magnetic conditions +interact. + +(1) In the first case, ordinary mechanical or translational energy is +spent as friction, an amount measurable in foot-pounds, and the factors +we know, a pressure into a distance. If the surface be of the same kind +of molecules, the whole energy is spent as heat, and is presently +radiated away. If the surfaces are of unlike molecules, the product is a +compound one, part heat, part electrical. What we have turned into the +machine we know to be a particular mode of motion. We have not changed +the amount of matter involved; indeed, we assume, without specifying and +without controversy, that matter is itself indestructible, and the +product, whether it be of one kind or another, can only be some form of +motion. Whether we can describe it or not is immaterial; but if we agree +that heat is vibratory molecular motion, and there be any other kind of +a product than heat, it too must also be some other form of motion. So +if one is to form a conception of the mechanical origin of electricity, +this is the only one he can have--transformed motion. + +[Illustration: FIG. 6.--Thermo-pile.] + +[Illustration: FIG. 7.--Dynamo.] + +(2) When heat is the antecedent of electricity, as in the thermo-pile, +that which is turned into the pile we know to be molecular motion of a +definite kind. That which comes out of it must be some equivalent +motion, and if all that went in were transformed, then all that came out +would be transformed, call it by what name we will and let its amount be +what it may. + +(3) When a conductor is moved in a magnetic field, the energy spent is +measurable in foot-pounds, as before, a pressure into a distance. The +energy appears in a new form, but the quantity of matter being +unchanged, the only changeable factor is the kind of motion, and that +the motion is molecular is evident, for the molecules are heated. +Mechanical or mass motion is the antecedent, molecular heat motion is +the consequent, and the way we know there has been some intermediate +form is, that heat is not conducted at the rate which is observed in +such a case. Call it by what name one will, some form of motion has been +intermediate between the antecedent and the consequent, else we have +some other factor of energy to reckon with than ether, matter and +motion. + +(4) In a galvanic battery, the source of electricity is chemical action; +but what is chemical action? Simply an exchange of the constituents of +molecules--a change which involves exchange of energy. Molecules capable +of doing chemical work are loaded with energy. The chemical products of +battery action are molecules of different constitution, with smaller +amounts of energy as measured in calorics or heat units. If the results +of the chemical reaction be prevented from escaping, by confining them +to the cell itself, the whole energy appears as heat and raises the +temperature of the cell. If a so-called circuit be provided, the energy +is distributed through it, and less heat is spent in the cell, but +whether it be in one place or another, the mass of matter involved is +not changed, and the variable factor is the motion, the same as in the +other cases. The mechanical conceptions appropriate are the +transformation of one kind of motion into another kind by the mechanical +conditions provided. + +[Illustration: FIG. 8.--Galvanic Battery.] + +(5) Physiological antecedents of electricity are exemplified by the +structure and mode of operation of certain muscles (Fig. 9, _a_) in the +torpedo and other electrical animals. The mechanical contraction of them +results in an electrical excitation, and, if a proper circuit be +provided, in an electric current. The energy of a muscle is derived from +food, which is itself but a molecular compound loaded with energy of a +kind available for muscular transformation. Bread-and-butter has more +available energy, pound for pound, than has coal, and can be substituted +for coal for running an engine. It is not used, because it costs so much +more. There is nothing different, so far as the factors of energy go, +between the food of an animal and the food of an engine. What becomes of +the energy depends upon the kind of structure it acts on. It may be +changed into translatory, and the whole body moves in one direction; or +into molecular, and then appears as heat or electrical energy. + +If one confines his attention to the only variable factor in the energy +in all these cases, and traces out in each just what happens, he will +have only motions of one sort or another, at one rate or another, and +there is nothing mysterious which enters into the processes. + +We will turn now to the mode in which electricity manifests itself, and +what it can do. It may be well to point out at the outset what has +occasionally been stated, but which has not received the philosophical +attention it deserves--namely, that electrical phenomena are reversible; +that is, any kind of a physical process which is capable of producing +electricity, electricity is itself able to produce. Thus to name a few: +If mechanical motion develops electricity, electricity will produce +mechanical motion; the movement of a pith ball and an electric motor are +examples. If chemical action can produce it, it will produce chemical +action, as in the decomposition of water and electro-plating. As heat +may be its antecedent, so will it produce heat. If magnetism be an +antecedent factor, magnetism may be its product. What is called +induction may give rise to it in an adjacent conductor, and, likewise, +induction may be its effect. + +[Illustration: FIG. 9.--Torpedo.] + +[Illustration: FIG. 10.--Dynamo and Motor.] + +Let us suppose ourselves to be in a building in which a steam-engine is +at work. There is fuel, the furnace, the boiler, the pipes, the engine +with its fly-wheel turning. The fuel burns in the furnace, the water is +superheated in the boiler, the steam is directed by the pipes, the +piston is moved by the steam pressure, and the fly-wheel rotates +because of proper mechanism between it and the piston. No one who has +given attention to the successive steps in the process is so puzzled as +to feel the need of inventing a particular force, or a new kind of +matter, or any agency, at any stage of the process, different from the +simple mechanical ones represented by a push or a pull. Even if he +cannot see clearly how heat can produce a push, he does not venture to +assume a genii to do the work, but for the time is content with saying +that if he starts with motion in the furnace and stops with the motion +of the fly-wheel, any assumption of any other factor than some form of +motion between the two would be gratuitous. He can truthfully say that +he understands the _nature_ of that which goes on between the furnace +and the wheel; that it is some sort of motion, the particular kind of +which he might make out at his leisure. + +Suppose once more that, across the road from an engine-house, there was +another building, where all sorts of machines--lathes, planers, drills, +etc.--were running, but that the source of the power for all this was +out of sight, and that one could see no connection between this and the +engine on the other side of the street. Would one need to suppose there +was anything mysterious between the two--a force, a fluid, an immaterial +something? This question is put on the supposition that one should not +be aware of the shaft that might be between the two buildings, and that +it was not obvious on simple inspection how the machines got their +motions from the engine. No one would be puzzled because he did not know +just what the intervening mechanism might be. If the boiler were in the +one building, and the engine in the other with the machines, he could +see nothing moving between them, even if the steam-pipes were of glass. +If matter of any kind were moving, he could not see it there. He would +say there _must_ be something moving, or pressure could not be +transferred from one place to the other. + +Substitute for the furnace and boiler a galvanic battery or a dynamo; +for the machines of the shop, one or more motors with suitable wire +connections. When the dynamo goes the motors go; when the dynamo stops +the motors stop; nothing can be seen to be turning or moving in any way +between them. Is there any necessity for assuming a mysterious agency, +or a force of a _nature_ different from the visible ones at the two ends +of the line? Is it not certain that the question is, How does the motion +get from one to the other, whether there be a wire or not? If there be a +wire, it is plain that there is motion in it, for it is heated its whole +length, and heat is known to be a mode of motion, and every molecule +which is thus heated must have had some antecedent motions. Whether it +be defined or not, and whether it be called by one name or another, are +quite immaterial, if one is concerned only with the _nature_ of the +action, whether it be matter or ether, or motion or abracadabra. + +Once more: suppose we have a series of active machines. (Fig. 11.) An +arc lamp, radiating light-waves, gets its energy from the wire which is +heated, which in turn gets its energy from the electric current; that +from a dynamo, the dynamo from a steam-engine; that from a furnace and +the chemical actions going on in it. Let us call the chemical actions A, +the furnace B, the engine C, the dynamo D, the electric lamp E, the +ether waves F. (Fig. 12.) + +[Illustration: FIG. 11.] + +The product of the chemical action of the coal is molecular motion, +called heat in the furnace. The product of the heat is mechanical motion +in the engine. The product of the mechanical motion is electricity in +the dynamo. The product of the electric current in the lamp is +light-waves in the ether. No one hesitates for an instant to speak of +the heat as being molecular motion, nor of the motions of the engine as +being mechanical; but when we come to the product of the dynamo, which +we call electricity, behold, nearly every one says, not that he does not +know what it is, but that no one knows! Does any one venture to say he +does not know what heat is, because he cannot describe in detail just +what goes on in a heated body, as it might be described by one who saw +with a microscope the movements of the molecules? Let us go back for a +moment to the proposition stated early in this book, namely, that if any +body of any magnitude moves, it is because some other body in motion and +in contact with it has imparted its motion by mechanical pressure. +Therefore, the ether waves at F (Fig. 11) imply continuous motions of +some sort from A to F. That they are all motions of ordinary matter from +A to E is obvious, because continuous matter is essential for the +maintenance of the actions. At E the motions are handed over to the +ether, and they are radiated away as light-waves. + +[Illustration: FIG. 12.] + +[Illustration: FIG. 13.] + +A puzzling electrical phenomenon has been what has been called its +duality-states, which are spoken of as positive and negative. Thus, we +speak of the positive plate of a battery and the negative pole of a +dynamo; and another troublesome condition to idealize has been, how it +could be that, in an electric circuit, there could be as much energy at +the most remote part as at the source. But, if one will take a limp +rope, 8 or 10 feet long, tie its ends together, and then begin to twist +it at any point, he will see the twist move in a right-handed spiral on +the one hand, and in a left-handed spiral on the other, and each may be +traced quite round the circuit; so there will be as much twist, as much +motion, and as much energy in one part of the rope as in any other; and +if one chooses to call the right-handed twist positive, and the +left-handed twist negative, he will have the mechanical phenomenon of +energy-distribution and the terminology, analogous to what they are in +an electric conductor. (Fig. 13.) Are the cases more dissimilar than the +mechanical analogy would make them seem to be? + +Are there any phenomena which imply that rotation is going on in an +electric conductor? There are. An electric arc, which is a current in +the air, and is, therefore, less constrained than it is in a conductor, +rotates. Especially marked is this when in front of the pole of a +magnet; but the rotation may be noticed in an ordinary arc by looking at +it with a stroboscope disk, rotated so as to make the light to the eye +intermittent at the rate of four or five hundred per second. A ray of +plane polarized light, parallel with a wire conveying a current, has its +plane of vibration twisted to the right or left, as the current goes +one way or the other through the wire, and to a degree that depends upon +the distance it travels; not only so, but if the ray be sent, by +reflection, back through the same field, it is twisted as much more--a +phenomenon which convinces one that rotation is going on in the space +through which the ray travels. If the ether through which the ray be +sent were simply warped or in some static stress, the ray, after +reflection, would be brought back to its original plane, which is not +the case. This rotation in the ether is produced by what is going on in +the wire. The ether waves called light are interpreted to imply that +molecules originate them by their vibrations, and that there are as many +ether waves per second as of molecular vibrations per second. In like +manner, the implication is the same, that if there be rotations in the +ether they must be produced by molecular rotation, and there must be as +many rotations per second in the ether as there are molecular rotations +that produce them. The space about a wire carrying a current is often +pictured as filled with whorls indicating this motion (Fig. 14), and one +must picture to himself, not the wire as a whole rotating, but each +individual molecule independently. But one is aware that the molecules +of a conductor are practically in contact with each other, and that if +one for any reason rotates, the next one to it would, from frictional +action, cause the one it touched to rotate in the opposite direction, +whereas, the evidence goes to show that all rotation is in the same +direction. + +[Illustration: FIG. 14.] + +How can this be explained mechanically? Recall the kind of action that +constitutes heat, that it is not translatory action in any degree, but +vibratory, in the sense of a change of form of an elastic body, and +this, too, of the atoms that make up the molecule of whatever sort. Each +atom is so far independent of every other atom in the molecule that it +can vibrate in this way, else it could not be heated. The greater the +amplitude of vibration, the more free space to move in, and continuous +contact of atoms is incompatible with the mechanics of heat. There must, +therefore, be impact and freedom alternating with each other in all +degrees in a heated body. If, in any way, the atoms themselves _were_ +made to rotate, their heat impacts not only would restrain the +rotations, but the energy also of the rotation motion would increase the +vibrations; that is, the heat would be correspondingly increased, which +is what happens always when an electric current is in a conductor. It +appears that the cooler a body is the less electric resistance it has, +and the indications are that at absolute zero there is no resistance; +that is, impacts do not retard rotation, but it is also apparent that +any current sent through a conductor at that temperature would at once +heat it. This is the same as saying that an electric current could not +be sent through a conductor at absolute zero. + +So far, mechanical conceptions are in accordance with electrical +phenomena, but there are several others yet to be noted. Electrical +phenomena has been explained as molecular or atomic phenomena, and there +is one more in that category which is well enough known, and which is so +important and suggestive, that the wonder is its significance has not +been seen by those who have sought to interpret electrical phenomena. +The reference is to the fact that electricity cannot be transmitted +through a vacuum. An electric arc begins to spread out as the density of +the air decreases, and presently it is extinguished. An induction spark +that will jump two or three feet in air cannot be made to bridge the +tenth of an inch in an ordinary vacuum. A vacuum is a perfect +non-conductor of electricity. Is there more than one possible +interpretation to this, namely, that electricity is fundamentally a +molecular and atomic phenomenon, and in the absence of molecules cannot +exist? One may say, "Electrical _action_ is not hindered by a vacuum," +which is true, but has quite another interpretation than the implication +that electricity is an ether phenomenon. The heat of the sun in some way +gets to the earth, but what takes place in the ether is not +heat-transmission. There is no heat in space, and no one is at liberty +to say, or think, that there can be heat in the absence of matter. + +When heat has been transformed into ether waves, it is no longer heat, +call it by what name one will. Formerly, such waves were called +heat-waves; no one, properly informed, does so now. In like manner, if +electrical motions or conditions in matter be transformed, no matter +how, it is no longer proper to speak of such transformed motions or +conditions as electricity. Thus, if electrical energy be transformed +into heat, no one thinks of speaking of the latter as electrical. If the +electrical energy be transformed into mechanical of any sort, no one +thinks of calling the latter electrical because of its antecedent. If +electrical motions be transformed into ether actions of any kind, why +should we continue to speak of the transformed motions or energy as +being electrical? Electricity may be the antecedent, in the same sense +as the mechanical motion of a bullet may be the antecedent of the heat +developed when the latter strikes the target; and if it be granted that +a vacuum is a perfect non-conductor of electricity, then it is +manifestly improper to speak of any phenomenon in the ether as an +electrical phenomenon. It is from the failure to make this distinction +that most of the trouble has come in thinking on this subject. Some have +given all their attention to what goes on in matter, and have called +that electricity; others have given their attention to what goes on in +the ether, and have called that electricity, and some have considered +both as being the same thing, and have been confounded. + +Let us consider what is the relation between an electrified body and the +ether about it. + +When a body is electrified, the latter at the same time creates an ether +stress about it, which is called an electric field. The ether stress may +be considered as a warp in the distribution of the energy about the body +(Fig. 15), by the new positions given to the molecules by the process of +electrification. It has been already said that the evidence from other +sources is that atoms, rather than molecules, in larger masses, are what +affect the ether. One is inclined to inquire for the evidence we have as +to the constitution of matter or of atoms. There is only one hypothesis +to-day that has any degree of probability; that is, the vortex-ring +theory, which describes an atom as being a vortex-ring of ether in the +ether. It possesses a definite amount of energy in virtue of the motion +which constitutes it, and this motion differentiates it from the +surrounding ether, giving it dimensions, elasticity, momentum, and the +possibility of translatory, rotary, vibratory motions, and combinations +of them. Without going further into this, it is sufficient, for a +mechanical conception, that one should have so much in mind, as it will +vastly help in forming a mechanical conception of reactions between +atoms and the ether. An exchange of energy between such an atom and the +ether is not an exchange between different kinds of things, but between +different conditions of the same thing. Next, it should be remembered +that all the elements are magnetic in some degree. This means that they +are themselves magnets, and every magnet has a magnetic field unlimited +in extent, which can almost be regarded as a part of itself. If a magnet +of any size be moved, its field is moved with it, and if in any way the +magnetism be increased or diminished, the field changes correspondingly. + +[Illustration: FIG. 15.] + +Assume a straight bar electro-magnet in circuit, so that a current can +be made intermittent, say, once a second. When the circuit is closed and +the magnet is made, the field at once is formed and travels outwards at +the rate of 186,000 miles per second. When the current stops, the field +adjacent is destroyed. Another closure develops the field again, which, +like the other, travels outwards; and so there may be formed a series of +waves in the ether, each 186,000 miles long, with an electro-magnetic +antecedent. If the circuit were closed ten times a second, the waves +would be 18,600 miles long; if 186,000 times a second, they would be but +one mile long. If 400 million of millions times a second, they would be +but the forty-thousandth of an inch long, and would then affect the eye, +and we should call them light-waves, but the latter would not differ +from the first wave in any particular except in length. As it is proved +that such electro-magnetic waves have all the characteristics of light, +it follows that they must originate with electro-magnetic action, that +is, in the changing magnetism of a magnetic body. This makes it needful +to assume that the atoms which originate waves are magnets, as they are +experimentally found to be. But how can a magnet, not subject to a +varying current, change its magnetic field? The strength or density of a +magnetic field depends upon the form of the magnet. When the poles are +near together, the field is densest; when the magnet is bent back to a +straight bar, the field is rarest or weakest, and a change in the form +of the magnet from a U-form to a straight bar would result in a change +of the magnetic field within its greatest limits. A few turns of +wire--as has been already said--wound about the poles of an ordinary +U-magnet, and connected to an ordinary magnetic telephone, will enable +one, listening to the latter, to hear the pitch of the former loudly +reproduced when the magnet is struck like a tuning-fork, so as to +vibrate. This shows that the field of the magnet changes at the same +rate as the vibrations. + +Assume that the magnet becomes smaller and smaller until it is of the +dimensions of an atom, say for an approximation, the fifty-millionth of +an inch. It would still have its field; it would still be elastic and +capable of vibration, but at an enormously rapid rate; but its vibration +would change its field in the same way, and so there would be formed +those waves in the ether, which, because they are so short that they can +affect the eye, we call light. The mechanical conceptions are +legitimate, because based upon experiments having ranges through nearly +the whole gamut as waves in ether. + +The idea implies that every atom has what may be loosely called an +electro-magnetic grip upon the whole of the ether, and any change in the +former brings some change in the latter. + +Lastly, the phenomenon called induction may be mechanically conceived. + +It is well known that a current in a conductor makes a magnet of the +wire, and gives it an electro-magnetic field, so that other magnets in +its neighbourhood are twisted in a way tending to set them at right +angles to the wire. Also, if another wire be adjacent to the first, an +electric current having an opposite direction is induced in it. Thus: + +Consider a permanent magnet A (Fig. 15), free to turn on an axis in the +direction of the arrow. If there be other free magnets, B and C, in +line, they will assume such positions that their similar poles all point +one way. Let A be twisted to a position at right angles, then B will +turn, but in the opposite direction, and C in similar. That is, if A +turn in the direction of the hands of a clock, B and C will turn in +opposite directions. These are simply the observed movements of large +magnets. Imagine that these magnets be reduced to atomic dimensions, yet +retaining their magnetic qualities, poles and fields. Would they not +evidently move in the same way and for the same reason? If it be true, +that a magnet field always so acts upon another as to tend by rotation +to set the latter into a certain position, with reference to the stress +in that field, then, _wherever there is a changing magnetic field, there +the atoms are being adjusted by it_. + +[Illustration: FIG. 16.] + +Suppose we have a line of magnetic needles free to turn, hundreds or +thousands of them, but disarranged. Let a strong magnetic field be +produced at one end of the line. The field would be strongest and best +conducted along the magnet line, but every magnet in the line would be +compelled to rotate, and if the first were kept rotating, the rotation +would be kept up along the whole line. This would be a mechanical +illustration of how an electric current travels in a conductor. The +rotations are of the atomic sort, and are at right angles to the +direction of the conductor. + +That which makes the magnets move is inductive magnetic ether stress, +but the advancing motion represents mechanical energy of rotation, and +it is this motion, with the resulting friction, which causes the heat in +a conductor. + +What is important to note is, that the action in the ether is not +electric action, but more properly the result of electro-magnetic +action. Whatever name be given to it, and however it comes about, there +is no good reason for calling any kind of ether action electrical. + +Electric action, like magnetic action, begins and ends in matter. It is +subject to transformations into thermal and mechanical actions, also +into ether stress--right-handed or left-handed--which, in turn, can +similarly affect other matter, but with opposite polarities. + +In his _Modern Views of Electricity_, Prof. O. J. Lodge warns us, quite +rightly, that perhaps, after all, there is no such _thing_ as +electricity--that electrification and electric energy may be terms to be +kept for convenience; but if electricity as a term be held to imply a +force, a fluid, an imponderable, or a thing which could be described by +some one who knew enough, then it has no degree of probability, for +spinning atomic magnets seem capable of developing all the electrical +phenomena we meet. 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