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 movedon 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 reboundin a planeat 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 reasonsit 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 evidencefor 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 tomatter 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 airmoves 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 notseemed 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 oppositedirection—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 ÆOLOTROPIC.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 themotion 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 theelements 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, Mendeléeff, 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 aprevious 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 tomake 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 nebulæ, 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 agiven 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, andvice versâ, some sort of mechanism is needful for transforming one kindinto 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 arc 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;whichone of these depends upon the character of the mechanism upon which the radiant energy acts, but the radiant energy itself, which consists ofether-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 continuesto 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 materialand 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 have186,000 × 5280 × 12= 400,000,000,000,000, nearly.1/40,000This 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 ofparts 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 directionand 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 beadopted, 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 ofmatter 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 verysmall, 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 itsidentity 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 calledHeat 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 happenedin 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, anddegrees 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-thousandthof 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 nebulæ, 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 forthinking 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 thatmetaphysical 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 tocompletely 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.
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 movedon 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 reboundin a planeat 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.
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 movedon 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 reboundin a planeat 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 reasonsit 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.
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.
The law of gravitation is held as being universal. According to it every particle of matter in the universe attracts every other particle. The evidencefor 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.
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 tomatter 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.
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 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 airmoves 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 notseemed 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 oppositedirection—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.
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 themotion 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.
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.
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 theelements 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.
It is possible to arrange the elements in the order of their atomic weights in columns which will show communities of property. Newlands, Mendeléeff, 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.
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 aprevious 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 tomake 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 nebulæ, 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 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 agiven 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.
As each different kind of energy represents some specific form of motion, andvice versâ, some sort of mechanism is needful for transforming one kindinto 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 arc 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;whichone of these depends upon the character of the mechanism upon which the radiant energy acts, but the radiant energy itself, which consists ofether-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.
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 continuesto be vibratory, and no transforming change can take place in the absence of matter. The ether is helpless.
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 materialand 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 × 5280 × 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 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 ofparts 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 directionand 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 beadopted, but the inappropriateness of the one word for the different phenomena has long been felt.
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 ofmatter 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.
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 verysmall, 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.
So long as heat was thought to be some kind of an imponderable thing, which might retain itsidentity 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 calledHeat 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 happenedin 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, anddegrees 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 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.
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-thousandthof 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 nebulæ, 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 forthinking 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 thatmetaphysical 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 tocompletely 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.