ART. 24. Centrifugal Force.—I have already shown in Art. 10 that the Centripetal Force and Universal Attraction are one and the same; as the Centripetal Force always acts towards the centre, and must therefore be in its operation and influence a gravitating or attractive power.

I have also pointed out in the same article, the necessity of another force, which is to be the complement, and the counter part of Gravitation Attraction. That complement and counter force was conceived by Newton, and called by him the Centrifugal Force. The very nature of the Centripetal Force demands and necessitates a force which in its mode of operation is exactly the opposite of the Centripetal Force. Unless there were such a force, a repellent and repulsive force, then instead of there being that harmonious working of the universe that now exists, there must inevitably be a gradual drawing together of all planets and satellites, of all stars and suns, into one vast, solitary, and ruinous body.

There are also other phenomena which demand a Centrifugal Force in the universe. It is a well-known fact, that there exist between the orbits of Jupiter and Mars, what are called planetoids, about 500 in number, which are supposed to be the remnants of a broken or shattered world. As may be expected from such an accumulation, they present the most extraordinary diversities and eccentricities in the orbits that can possibly be conceived. They are of all shapes and sizes, and besides their orbits round the sun, have orbits among themselves. They are so clustered together that their orbits intersect each other at numerous points, and when in conjunction are said to suffer great perturbations, being pulled great distances this way and that by each other's attractive influence. It is further stated that their orbits so intersect each other, that if they were imagined to be material rings, they would be inseparable, and the whole could be suspended by taking any one of them up at random. Here, then, is presented to us a kind or order of celestial phenomena for whose well-being and effectual working the Centripetal Force or the Attraction of Gravitation cannot possibly account. In their case another force is demanded which shall be the exact complement and counterpart of the Centripetal Force. There needs therefore a force, not an imagined one, simply conceived to fill a want, but a real Force, as real and as plainly to be understood as the Centripetal Force. A force existing in each world just like the Attraction of Gravitation, only the reverse of Gravitation, a repellent, repulsive Force, acting in the reverse mode, and way, to universal attraction. This Force must be governed by the same rules and laws that govern the Centripetal Force, if it is to work in harmony with the same. It must be universal in its character, having a proportion of forces equal to the product of the masses of the two bodies which are concerned, and its path must coincide with the path of gravitational attraction, that is, in the straight line which joins the centres of gravity of the two bodies. Further, and what is perhaps the most important of all, it must act as a repelling or repulsive force which shall be in the same proportion in regard to distance, as the law governing Centripetal Force, that is, inversely as the square of the distance.

Again, and briefly, there are also in existence small bodies called meteors, which are said to exist by myriads, which float in space, and circle round the sun. They are of all shapes and sizes, from one ounce to a ton or even tons, thousands of them coming into contact with our earth's atmosphere every year, especially in August and November. All of these small bodies have orbits among themselves, and gravitate round one another, as they revolve round the sun. Now if the orbits of the planetoids be such an entangled mass, what must be the orbits of these meteors? What an indescribable, unimaginable mass of labyrinthian motions must exist among these myriads of little bodies! How they must intersect, cross and intermingle each other's orbits! What attraction and counter-attraction they must exert upon each other! Let me ask any man to sit down and try to imagine how the present recognized Centripetal and Centrifugal Forces can account for the effectual working of these meteors. As illustrating the necessity of a real and physical Centrifugal Force which is to be the exact counterpart of the Centripetal Force, I would call the attention of the reader to Herschel's view of this matter. In dealing with the phenomena of comets' tails he writes:[1] "Beyond a doubt, the widest and most interesting prospect of future discovery, which this study holds out to us, is, that distinction between gravitating and levitating matter, that positive and irrefutable demonstration in nature of a repulsive force, co-extensive with, but enormously more powerful than the attractive force we call gravity which the phenomena of their tails afford." I premise that this prophecy of Herschel's will be fully demonstrated and proved in the succeeding pages of this work. For, in the theory of the Aether that is to be afterwards perfected, it will be philosophically proved that the physical medium so conceived will satisfactorily account for a force or motion from the centre of all bodies; which motions fulfil all the conditions required by that Centrifugal Force, which is the complement and counterpart of the Attraction of Gravitation. At the present time, with the conception of a frictionless Aether, it is impossible to harmonize the existence of such a force or motion with our theory of the Aether. Yet Professor Lebedew of Moscow, and Nichols and Hull of America, have incontrovertibly demonstrated by actual experiments the existence of such a force. Therefore it follows, that if our present theory of the Aether fails to agree with experimental evidence, such a theory must be reconstructed in order that our philosophy may be made to agree with our experiments and our experience.

[Footnote 1: Lectures on Scientific Subjects.]

ART. 25. Kepler's Laws.—A long time before Newton had discovered the Law of Gravitation, Kepler had found out that the motions of the planets were governed by certain laws, and these came to be known as Kepler's Laws.

These laws which were given to the world by Kepler, simply represented facts or phenomena which had been discovered by observation, as Kepler was unable to account for them, or to give any mathematical basis for the same.

On the discovery, however, of Universal Gravitation, Newton saw at once that these laws were simply the outcome of the application of the Law of Gravitation to the planets, and that they could be accounted for on a mathematical basis by the Law of Gravitation, as they seemed to flow naturally from that law.

Kepler's Laws are three in number and may be thus stated—

1st Law. Each planet revolves round the sun in an elliptic orbit, with the sun occupying one of the Foci.

2nd Law. In the revolution of a planet round the sun, the Radius Vector describes equal areas in equal times.

3rd Law. The squares of the periodic times of planets are proportional to the cubes of their mean distances.

Now the question arises, whether it is possible to form a theory of the Aether which shall satisfactorily and philosophically account for all the phenomena associated with Kepler's Laws in their relation to the motions of planets, satellites, or other solar bodies? On the present conception of the Aether such a result is an absolute impossibility. With the theory of the Aether, however, to be submitted to the reader in this work, the result is possible and attainable. If, therefore, such a result is philosophically proved, as I submit will be done, then we shall have greater evidence still that the theory so propounded is a more perfect theory than the one at present recognized by scientists generally.

ART. 26. Kepler's First Law.—Each planet revolves round the sun in an elliptic orbit, the sun occupying one of the Foci.

The ancients thought that the paths of the planets around the sun were circular in form, because they held that circular motion was perfect. A system of circular orbits for the paths of the planets round the sun would be very simple in its conception, and would be full of beauty and harmony. But exact calculations reveal to us that the path of a planet is not exactly that of a circle, as the distance of a planet from the sun in various parts of its orbit is sometimes greater, and sometimes less, than its mean distance.

The planet Venus has the nearest approach to a circular orbit, as there are only 500,000 miles between the mean, and greatest and least distances, but both Mercury and Mars show great differences between their greatest and least distances from the sun.

If, therefore, the orbits of a planet are not exactly circular, what is their exact shape? Kepler solved this problem, and proved that the exact path of a planet round its central body the sun was that of an ellipse, or an elongated circle. Thus he gave to the world the first of his famous laws which stated that each planet revolves round the sun in an orbit which has an elliptic form, the sun occupying one of the Foci.

Not only is the orbit of a planet round the sun elliptic in form, but the path of the moon round the earth, or the path of any satellite, as for example a satellite of Mars or Jupiter or Saturn, is also that of an ellipse, the planet round which it revolves occupying one of the Foci.

It has also been found that certain comets have orbits which cannot be distinguished from that of an elongated ellipse, the sun occupying one of the Foci.

Now let us apply the Law of Gravitation to Kepler's First Law, and note carefully its application.



Let A, B, C, D be an ellipse representing the orbit of the earth, and let S represent the sun situated at one of the Foci.

We will suppose that the earth is projected into space at the point A, then according to the First Law of Motion, it would proceed in a straight line in the direction of A E, if there were no other force acting upon the earth. But it is acted upon by the attraction of the sun, that is the Centripetal Force which is exerted along the straight line S A (Art. 20), which continues to act upon it according to the principle already explained in Arts. 21 and 22.

Now, according to the Second Law of Motion and the Parallelogram of Forces, instead of the earth going off at a tangent in the direction of A E, it will take a mean path in the direction of A B, its path being curved instead of being a straight line.

If the sun were stationary in space, then the mean distance, that is, the length of the imaginary straight line joining the sun S A to the earth, would remain unaltered. The Radius Vector S A, or the straight line referred to, would then be perpendicular to the tangent, and the velocity of the earth round the sun would be uniform, its path being that of a circle.

The Radius Vector S A, however, is not always perpendicular to the tangent F E, and therefore the velocity of the earth is not always uniform in its motion in its orbit, as sometimes it travels at a lesser or greater speed than its average speed, which is about 18 miles per second.

It has to be remembered that the sun itself is in motion, having a velocity through space of about 4-1/2 miles per second, so that, while the earth is travelling from A to B the sun is also travelling in the direction of S B. Thus the orbital velocity of the earth, and the orbital velocity of the sun, together with the Centripetal Force or universal Gravitation Attraction, are all acting in the same direction when the earth is travelling from A to B, that is, in the direction of the orbit situated at B. This point of the orbit is known as the perihelion, and at that point the velocity of the earth is at its greatest, because the earth is then nearest the sun.

According to Newton, the planet when at B would still have a tendency to fly off into space owing to its Centrifugal Force, but it is held in check by the Centripetal Force, so that instead of it flying off into space, it is whirled round and starts off on its journey away from the sun in the direction of B, C. The sun, however, is still continuing its journey in the direction of S, H, so that not only is the increased orbital velocity of the earth, which it obtained at its perihelion, urging the earth away from the sun, but the sun itself in its advance through space is leaving the earth behind it. The combined effect of the two motions, the advancing motion of the sun, and the receding motion of the earth, due to its increased orbital velocity, drives the earth towards the aphelion, where its distance from the sun is greatest, and its orbital velocity is the least.

By the time the planet has arrived at point C, its motion through space has gradually decreased, and the Centripetal Force begins to re-assert itself, with the result that the earth is slowly made to proceed towards the point D of the ellipse, at which point its motion is the slowest in orbital velocity, only travelling about 16 miles per second, while the distance of the earth from the sun is the greatest and has increased from 91,000,000 miles at the perihelion to 94,500,000. This point of the orbit is known as its aphelion.

After rounding this point, the orbital velocity of the earth begins to increase again, owing to the diminishing distance of the earth from the sun, which according to the law of inverse squares (Art. 22) gives an added intensity to the Centripetal Force.

Thus by the combination of the Laws of Motion and the Law of Gravitation discovered by Newton, he was able to satisfactorily account for and explain on a mathematical basis, the reason why the earth and all the other planets move round the sun in elliptic orbits, according to Kepler's First Law.

In the development of the physical cause of gravitation, therefore, the same physical medium, which accounts for that law, must also give a satisfactory explanation of the first of Kepler's Laws.

ART. 27. Kepler's Second Law.—This law states that the Radius Vector describes equal areas in equal times. The Radius Vector is the imaginary straight line joining the centres of the sun and the earth or planet. While the First Law shows us the kind of path which a planet takes in revolving round the sun, the Second Law describes how the velocity of the planet varies in different parts of its orbit.

If the earth's orbit were a circle, it can be readily seen that equal areas would be traversed in equal times, as the distance from the sun would always be the same, so that the Radius Vector being of uniform length, the rate of motion would be uniform, and consequently equal areas would be traversed in equal times. Take as an illustration the earth, which describes its revolution round the sun in 365-1/4 days. Now if the orbit of the earth were circular, then equal parts of the earth's orbit would be traversed by the Radius Vector in equal times. So that with a perfectly circular orbit, one half of the orbit would be traversed by the Radius Vector in half a year, one quarter in one quarter of a year, one-eighth in one-eighth of a year, and so on; the area covered by the Radius Vector being always exactly proportionate to the time.

From Kepler's First Law, however, we know that the planet's distance does vary from the sun, and therefore the Radius Vector is sometimes longer and sometimes shorter than when the earth is at its mean distance; the Radius Vector being shortest at the perihelion of the orbit, and longest at the aphelion. We learn from Kepler's Second Law that when the Radius Vector is shortest, that is, when the planet is nearest the sun, it acquires its greatest orbital velocity; and when the Radius Vector is longest, that is, when the planet is farthest from the sun, the orbital velocity of a planet is the slowest.

Let A, B, D, C represent the elliptic orbit of a planet, with S sun at one of the Foci, and let the triangles A, S, B and D, S, C be triangles of equal area. Then, according to Kepler's Second Law, the time taken for the Radius Vector to traverse the area A, S, B is equal to the time that the Radius Vector takes to traverse the area D, S, C. So that the planet would take an equal time in going from A to B of its orbit, as it would take in going from D to C. Thus the nearer the planet is to the sun, the greater is its orbital velocity, and the farther it is away from the sun the slower is its velocity, the velocity being regulated by the distance. The manner in which the difference of velocity is accounted for by the Law of Gravitation has already been explained in the preceding article. Thus Newton proved that Kepler's Second Law was capable of being mathematically explained, and accounted for, by the universal Law of Gravitation.



If, therefore, a physical cause can be given for Newton's Law of Gravitation, then such physical cause must also be able to account for, and that on a strictly philosophical basis, the second of Kepler's Laws as well as the first.

ART. 28. Kepler's Third Law.—The Third Law of Kepler gives the relation between the periodic time of a planet, and its distance from the sun. The periodic time of any planet is the time which it takes to go once round the sun. Thus the periodic time of the earth is 365-1/4 days. The periodic time of Venus is 224.7 days, while that of Mars is 686.9 days.

Kepler had found out that different planets had different periodic times; he also found out that the greater the mean distance of the planet, the greater was the time which the planet took to perform its journey round the sun, and so he set to work to find out the relationship of the periodic time to the planet's mean distance.

After many trials and many failures he arrived at the right conclusion, and at last discovered the true law which is known as Kepler's Third Law, which states that for each and every planet, the squares of their periodic times are proportional to the cubes of their mean distances.

For purposes of illustration let us take the earth and the planet Venus and compare these two. The periodic time of the earth is 365 days, omitting the quarter day. The periodic time of Venus is 224 days approximately. Now, according to Kepler's Third Law, the square of 365 is to the square of 224, as the cube of the earth's mean distance is to the cube of Venus's mean distance, which are 92.7 millions of miles and 67 millions of miles respectively. The problem may be thus stated—

As 365^2: 224^2:: 92.7^3: 67^3:

This worked out gives—

133,225: 50,176: 796,597.982: cube of Venus's mean distance.

So that by Kepler's Third Law, if we have the periodic time of any two planets, and the mean distance of either, we can find out the mean distance of the other by simple proportion.

In making astronomical calculations, the distances of the planets are generally obtained by means of Kepler's Third Law, as the periodic time of the planet is a calculation that may be made by astronomers with great certainty, and when once the periodic times are found, and the mean distance of a planet, as our earth for example, is known, the mean distances of all the other planets in the solar system may soon be obtained.

In like manner this Third Law of Kepler's is equally applicable to the satellites of any planet. For example, when the periodic time of both of Mars' satellites, Phobos and Deimos, are known, being about 8 hours and 30 hours respectively, and the distance of either is known, as Phobos with a mean distance of 5800 miles, then the mean distance of Deimos can easily be calculated by this law, and is found to be 14,500 miles.

As discovered by Kepler, the Third Law was simply the result of observation. He was unable to give any mathematical basis for its existence. The Laws as they were given to the world by Kepler were simply three great truths which had been discovered by observation. It rested with Newton to show how these laws could be accounted for on a mathematical basis, and to show how they all sprang from one and the same source, namely the universal Law of Gravitation. In his Principia, he proved that all Kepler's Laws were fully expounded and explained by his great discovery of Universal Gravitation.

Now what Newton has done for Kepler's Laws from the mathematical standpoint, we propose to do from the physical standpoint. In the development of the physical agency or cause of Gravitation, therefore, among the phenomena and laws, which have to be satisfactorily accounted for on a physical basis, are these three Laws of Kepler's just referred to.

So that in addition to the satisfactory explanation of a physical cause for the Laws of Motion, and the Centripetal and Centrifugal Forces, the hypothesis of a physical cause of Gravitation must fully and satisfactorily account for the Laws of Kepler, whose mathematical explanation was given by Newton.

Further, and what is as equally important, the explanation so given must be strictly in harmony with the Rules of Philosophy as laid down in Art. 3. That is, the explanation must be simple in character, must not be contrary to experience or observation, and must satisfactorily account for the laws which the hypothesis of the physical cause of Gravitation seeks to explain. This I premise we will do as we pass from stage to stage in the development of the theory.

I can safely premise that it will be simple in character and conception, that it will be entirely in harmony with all experience and observation, and that the physical cause so advanced will give as physical a basis to Kepler's Laws as Newton's mathematical calculations gave them a mathematical basis.

In summing up, I need hardly point out, that if all that I have premised in this and the preceding chapter is accomplished in the after chapters of this book, then for the first time since the discovery of Universal Gravitation by Sir Isaac Newton, his great discovery will have received the long-expected and long-desired physical explanation, that explanation and cause being founded on his own Rules of Philosophy given in his immortal Principia, and for the first time our Philosophy will be brought strictly into harmony with our universal experience.



CHAPTER III

MATTER

ART. 29. What is Matter?—The law of Universal Attraction states that "Every particle of matter attracts every other particle," etc., and the question at once arises as to what is meant by the term Matter, what are its properties and its constitution? Tait, in his Natural Philosophy, gives the following as the definition: "Matter is that which can be perceived by the senses, or is that which can be acted upon by, or can exert force."

It has already been pointed out in Art. 13 that force is due to motion, and that wherever we get motion of any kind or sort, there we get energy, or what used to be termed force. The consideration of this phase of the question will be more fully dealt with in the chapter on Energy and Motion. Suffice to say, that all experience teaches us that force is the outcome of motion.

Accepting this definition therefore of force, Tait's definition of matter will read thus, if brought up to date: "Matter is that which can be perceived by the senses, or is that which can be acted upon by motion, or which can exert motion."

The common idea that matter can only be that which can be seen or actually felt, is not large enough for a definition of Matter. There are numbers of things in Nature which cannot either be seen or felt, yet which are included in the term Matter. Let us take one or two examples. Every one admits that nitrogen and oxygen are matter, yet I venture to say that no one has actually seen or felt either of these gases. Both of these gases are colourless and invisible, and are both tasteless. You may open your mouth and inspire both gases, and yet if they are pure, you cannot taste either of them. They are only matter, in the sense that they appeal to our sense of force through the motion which they may acquire.

Or again, take air, which is a mechanical mixture of several gases. Can you see air? If it be free from vapour and smoke, air is invisible, and on a clear day you may look for miles across the sea, or from the top of a mountain, and yet not have your sight impeded in any way by the atmosphere. Neither can it be felt by the sense of touch. Open and shut your hand, and see if you can feel the air while you do so. In similar ways it may be demonstrated that the air is tasteless. So that it is not necessary for us to see, or feel, or taste, or even smell that which we term Matter, in order for it to be included in that term. So long as that which we term Matter is able to accept motion in any manner from any body that is either moving, or in a state of vibration, and not only accepts, but also transmits the vibratory, or the kinetic motion so called of the moving body, then that which accepts the motion is legitimately termed Matter.

It becomes perfectly clear, therefore, why air, aether, oxygen, and hydrogen are termed Matter. Because they can be all acted upon by motion, and after being so acted upon, they can exert motion upon some other body. Heat is a form of motion, and when heat acts upon the air, the latter is set in motion, and we have what are commonly known as winds. It is unnecessary for me to prove that the motion of winds can be transmitted to other matter, as we have numerous examples from our observation and experience, in the case of windmills driven by the motive power of the winds, and also balloons urged along by the same cause; apart from the devastating effect produced in towns and country by a hurricane or storm.

The point which I wish to emphasize is, that Matter, strictly defined, is that which can be acted upon by motion, such as heat or electricity, both being forms of motion, and which can exert the motion so derived upon some other body.

Wherever, therefore, in the universe we find any body, whether it be solid, liquid or gaseous, or any medium which can be acted upon by motion, and after being so acted upon, can exert motion, that body or medium may legitimately be included in the term Matter, although it may be absolutely invisible to the eyes, or insensible to the sense of touch, or taste, or smell. In the same work,[2] Tait states that in the physical universe there are but two classes of things, "Matter and Energy," and then goes on to give examples of both. He adds that a stone, piece of brass, water, air, aether, are particles of matter, while springs, water-power, wind, waves, heat and electric currents are examples of energy associated with Matter.

Now I may add here, that within these two statements is to be found the germ of the physical cause of Gravitation, together with the satisfactory explanation of all phenomena that the universe reveals to us, either by observation or by experiments. I purpose therefore, before giving any detailed accounts of that medium which is to form the physical basis for the cause of Gravitation, to look at the term Matter in all its aspects, in order that we may get a right conception of the universe, and of the part that Matter plays in the same.

[Footnote 2: Tait, Natural Philosophy.]

ART. 30. Conservation of Matter.—The Theory of the Indestructibility of Matter was first introduced by Lavoisier in 1789. This theory may be thus summed up; that Matter which fills the universe is unchangeable in quantity, so that the total quantity ever remains the same. Changes may take place in regard to the state of the Matter, but the sum-total of Matter throughout all the changes remains unaltered. Thus when we burn coal, it is changed into carbonic acid by combination with the oxygen of the atmosphere; when sugar is put into water, it simply passes from the solid to the liquid condition. If a piece of iron or steel is allowed to rust, the surface of the iron has entered into combination with the oxygen and water of the atmosphere, and formed a new substance. So that a body may change from solid to liquid, as for example from ice to water, or from liquid to a gaseous condition, as from water to steam, and probably from a gaseous condition to an aetherial condition as we shall see later on, but the sum-total of Matter throughout all these changes ever remains the same. Thus, throughout all the physical and chemical changes that Matter may undergo in the universe, there is no actual loss in weight or quantity. Throughout the whole realm of Nature we do not find a single instance of the production of absolutely new Matter. We may, and can produce new combinations of the forms of Matter. The substance so formed by chemical combination may be different from anything that has ever been seen or produced before, but the elements of which it is formed must have existed in some other form before its production.

This principle is the great underlying principle of all chemical investigation and research, and may be proved at any time by means of the scales or balance in the laboratory. Lavoisier first made the experiment with the scales and proved this truth by actual demonstration.

ART. 31. Matter is Atomic.—The hypothesis that Matter is made up of infinitely small particles which are termed atoms, was first proposed by the Grecian philosophers. This hypothesis has gradually taken definite shape, but it remained for Dalton to first put the hypothesis into a connected form, and that form is now known as Dalton's Atomic Theory.

According to this theory, an atom of hydrogen was the lightest atom known, but comparatively recent researches by Sir W. Crookes have shown that there are possibly in existence minute particles which are even lighter than an atom of hydrogen. Thus Sir W. Crookes has suggested that there are certain particles associated with an atom of hydrogen which are 700 times less in weight than the atom itself.

Professor J. J. Thompson has further suggested that if we could divide an atom into a thousand parts, and could take one of those parts, we should find that this corpuscle, as he has termed it, would be the carrier of the charges in an electric current, so that it will be seen that we are moving into the direction of the continuity of Matter. Let us now look at the question as to what is meant by an atom more fully.

ART. 32. What is an Atom?—Clerk Maxwell's definition of an atom is, "a body that cannot be cut in two." An atom is the smallest part of a simple substance which can enter into combination with another element, and is incapable of being further subdivided.

An atom of hydrogen is the smallest part of that particular gas which can enter into combination with any other element, as oxygen, to form a chemical compound as water, which is composed of two atoms of hydrogen and one of oxygen.

Further, an atom of any kind or sort, retains its identity and remains the same throughout all chemical combinations or physical changes which it may undergo. By spectroscopic analysis, it has been ascertained, for example, that hydrogen exists in the sun and stars, and the conclusion is arrived at in connection therewith, that an atom of hydrogen in any sun or star is the same as an atom of hydrogen in our atmosphere, or in any of the compounds, as water, in which it is found. Thus it has come to be received as an accepted fact, that every atom of any substance, as oxygen, nitrogen, and hydrogen, whether they exist in the earth or sun, in meteorites or the farthest stars or nebulae, wherever they are found, possesses the same identity and the same physical properties.

Atoms attract one another, and this atomic attraction is known as affinity. There is not the least possible doubt that affinity is a form of universal attraction, except that the affinity of atoms is selective. This affinity of atoms for each other gives rise to the combination of atoms known as molecules and chemical compounds.

Size of Atoms.—It has been computed by Lord Kelvin and others, that an atom may be as small as 1/50,000,000 of an inch in diameter, so that if 50,000,000 of them were put side by side, they would just measure one inch in length. Atoms are not all of the same size or weight. An atom of oxygen weighs 16 times as much as an atom of hydrogen. It has been proved by Kirchhoff and Bunsen, that the 3/1,000,000 part of a milligramme of sodium chloride is sufficient to give a yellow colour to a gas-jet. Faraday prepared some sheets of gold, so thin that he estimated they only measured the 1/100 part of the length of a light-wave. We have to remember that each sheet of gold must have contained molecules of gold composed of atoms. What must have been the size of the atoms therefore of which the sheet was composed?

ART. 33. The Atomic Theory.—The Atomic Theory was revived by Dalton in 1804, in order to account for the fact that elements unite in certain definite proportions. From that time to the present, the theory has grown and developed until at the present time it is looked upon as a well-established theory. It is, however, simply a theory, and from the very nature of the hypothesis is incapable of proof. No one has ever seen an atom of hydrogen or oxygen, or an atom of any solid, liquid, or gaseous matter. The Atomic Theory suggests, therefore, that there is a limit to the divisibility of matter. All chemical experiments lend support to the theory, and by it we are able to give an intelligible and easy method of expression to what would otherwise be difficult phenomena to explain.

Ancient philosophers were divided on the question of the infinite divisibility of matter. The Epicureans were of the opinion that matter was incapable of infinite division, and that even if we were able to make the smallest possible division, it would be impossible for us to reach the smallest particle termed "Atom."

ART. 34. Kinds of Atoms.—Various forms of atoms have been conceived by philosophers from time to time, ranging from the Hard Atom, and the simple point-centres of Boscovitch, until we come to the more modern Vortex Atom of Lord Kelvin, or the Strain Atom of Dr. Larmor, which will be looked at separately. Democritus conceived a hard atom as long ago as 500 B.C., while the notion of a hard atom is not absent from the works of Newton himself. We find that Newton suggested that the particles of air might be hard spherical bodies, at a distance from one another of about nine times their diameter.

The hard atom, however, seems to be refuted by spectroscopic analysis, which reveals to us in a manner that has never been revealed before, something of the sizes and vibrations of atoms.

From the phenomenon of heat, which is simply matter in motion, we feel compelled to accept the fact that an atom is not a hard particle, but that it is something which is more closely allied to the Vortex Atom, or the Strain Atom of Dr. Larmor.

Boscovitch Atom.—According to Boscovitch's theory, each atom is simply an indivisible point in space capable of motion, and possessing a certain mass whereby a certain amount of energy is required to produce a certain change of motion. In addition to this, any two atoms could attract or repel each other with a force depending upon their distance apart. The Law which regulates these forces for all distances greater than 1/1000 of an inch is an attraction varying inversely as the square of the distance, and a repulsion for less distances.

We have, therefore, to suppose that in place of the hard atom, there is merely a geometrical point which can exert attractive or repulsive forces to, or from, the central point. So far as external particles are concerned, they would behave just the same as a hard atom would do. This conception was largely entertained in recent times by Faraday. It is more a mathematical explanation than a physical one, but has been found convenient in explaining what takes place in the interior of bodies in their three states, namely: solid, liquid, and gaseous.

Lord Kelvin's Vortex Atom.—Another hypothesis which has been suggested for the constitution of an atom, is that known as the Vortex Atom, which received its birth at the hands of Lord Kelvin. The underlying principle of this Vortex Atom is, that matter may be entirely due to the rotating parts of a fundamental medium, the Aether, which fills all space.

The properties of vortex motion were first mathematically calculated by Helmholtz, but it was left to Sir Wm. Thompson, now Lord Kelvin, to give a physical idea of the Vortex Atom.

Before entering further into the question of the Vortex Atom, it may be as well to explain how vortex smoke rings may be made.



All that is required is a wooden box, about one cubic foot in size, with a round hole perforated in one of the sides, and the opposite side covered with a piece of linen in place of the wooden side. The bottom of the box should then be covered with some strong solution of ammonia, and some hydrochloric acid poured into a saucer and put into the box. The combination of these two will cause thick clouds to form in the box, and if the linen is sharply tapped by the hand, a ring of this cloud will be forced through the hole on the opposite side of the box. The ring so formed will be circular in shape, and will go sailing through the room in which it is made.

When the hole is circular, the rings will be found circular also, but if the hole is square, then the rings will be irregular in shape. One remarkable characteristic about these rings is, that when two of the rings are travelling in the same straight line, the one behind will overtake the front one, and while so doing, the diameter of the front one is enlarged, while that of the one behind contracts. The front one will also travel slower, while the one behind travels faster until it has caught up the former, and then the latter, having contracted sufficiently, will pass through the diameter of the former as illustrated in the figure. This alternation of contraction and expansion is continued as long as the two rings move in the same plane and until they are destroyed. When, however, the two rings are moving in opposite directions, and meeting each other in the same straight line, they will repel one another, instead of attracting each other.

Their rate of progress is gradually reduced as they approach together, and they begin to expand and enlarge, but they never touch each other. Another peculiar feature about the rings consists in the fact, that the central core of air in the ring remains the same all the time the ring is in motion through the room, so that it has the same core of air at the end of its journey as it had when it left the box.

As Lord Kelvin pointed out, if there were no friction of the air, the ring once created would rotate for ever. If, therefore, there were such a thing as a perfect fluid, and there were vortex rings in it, nothing could destroy these rings when once they were created, and this is one of the most striking suggestions with reference to the Vortex Atom theory of matter. It remains to be seen whether in the universe we have such a medium as a perfect fluid.

Sir Wm. Thompson has applied the Vortex Atom theory of matter to the Aether, but from mathematical calculation he was unable to arrive at a satisfactory conclusion as to the Aether being composed of vortex atoms.

Another remarkable property belonging to these rings, lies in the fact that they cannot be cut in two. It will be found that when the knife is brought near to them, they seem to recoil from the knife. In that sense, it is literally an atom, a thing which cannot be cut in two.

The Vortex Atom has many recommendations in its favour. Many of the most important properties of matter are possessed by it, as for example indestructibility, elasticity, inertia, compressibility, and its incapability to be cut in two. Further, it may be linked with another ring, and so give the basis to the combining properties of atomic weights.

The Vortex Atom theory is simple in character, as it does not postulate any extravagant hypothesis, but makes use of the Aether as the common basis for all matter, simply stating that this property of rotation may be the basis of all that we call matter. We shall further consider the relation of the Vortex Atom to matter, when we deal with the constitution of matter and the unity of the universe.

ART. 35. Elements of Matter.—As is well known, modern chemistry has succeeded in reducing all the complex forms of matter in Nature into a number of simple substances, which are called elements. Of these elements about seventy are at present known, some of which, however, are very rare. An element therefore is a simple substance which cannot be decomposed by any known force or process, as heat or electricity, into other elements.

There are, however, only about fourteen of these elements that enter largely into the constitution of the earth, the most common being oxygen and silicon. By the use of the spectroscope, it has been proved that many of these elements, as for example oxygen, hydrogen, sodium and calcium, exist in the sun and stars, as well as in the most distant nebulae. Most of the elementary bodies are to be found in a gaseous form as hydrogen, oxygen, fluorine and chlorine, though it has been found possible to liquefy even these gases. Thus we see that matter may be roughly divided into three states, viz. solid, liquid, or gaseous.

The condition in which the substance is found depends upon its temperature and pressure. An example of matter in its three stages is best shown in the case of water, where in the solid condition we have it as ice, in the liquid condition as water, and in the gaseous condition as steam.

By recent researches it has been found possible to liquefy gases at a very low temperature and increased pressure, with the result that now nearly all known gases as hydrogen, oxygen, and carbonic acid are to be obtained in liquid form. By still more recent experiments made by Professor Dewar, it has even become possible to liquefy the air we breathe, with the result that at a temperature of about 270 degrees below freezing-point and at an increased pressure, the otherwise invisible and gaseous air may be changed into a liquid, and poured out from one vessel into another in the same way that water can be poured out. A vessel, however, at the ordinary temperature into which such liquid air is poured, would be so hot compared with the coldness of the liquid air, that as soon as the exceedingly cold liquid air came into contact with the vessel, the comparatively hot vessel would make the liquid air to boil.

ART. 36. Three Divisions of Matter.—Matter has been divided into three divisions, viz. solid, liquid, and gaseous. These divisions are each known by characteristic qualities, which separate the one division from another. At the same time, it is possible for matter to pass from one division into another, as for example in the case of water, which may exist in solid, liquid, and gaseous form. In view of the recent researches of Sir. Wm. Crookes and Professor J. J. Thompson, it is very probable that before long we shall have to add a fourth division to matter, which we should have to call ultra-gaseous form, or it may possibly be the aetherial form. If it should prove to be true that Aether is matter, and possesses the essential qualities of matter as suggested by Lord Kelvin, then certainly we shall have reached the boundary of another great division of matter, and our conception of the divisions of matter will have to be enlarged to take in that form, so that matter would then be divided into four great divisions, viz. solid, liquid, gaseous, and aetherial.

We will now consider the three groups as at present recognized.

Solid.—Examples of solid bodies are common and familiar, and are typified by such things as iron, silver, copper, and lead. The chief characteristic of this condition of matter is that its condition or state is fixed, and cannot be altered without the expenditure of heat or electricity or some other form of energy.

All solid elementary substances, with the exception of carbon, can be melted or reduced to a molten condition, although some of them require a very high temperature to effect this reduction, as, for example, platinum. When a still higher temperature is applied, the metals may be vaporized, or reduced from a molten state to that of a vaporous condition. In the case of solids, the atoms have not a free path in which to move. It must not be thought, however, that the atoms of a solid are motionless, as there is nothing absolutely motionless in the universe. In the case of the solid, the molecules which compose it, preserve their relative position and are linked together in relation to each other by the force of Cohesion.

Liquid.—When matter is in a liquid condition, as, for example, water and oil, the condition of its molecules are not so fixed and stable as they are in the solid state. The molecules can move freely about one another, and their freedom is increased compared with their condition when in the solid state.

As already indicated, the reduction of a solid body to a liquid or molten state may be effected by heat. When heat is applied to a solid body, several results follow, each of which is the outcome of the other.

1. There is an increase of temperature which is due to the increased energy of the molecules, through the added heat.

2. There is an enlargement of the volume or size of the body, and if the addition of heat be continued, the molecular forces which hold the molecules together are broken down, and then the molecules, loosened from those forces which in the solid state have bound them together, begin to move about with greater freedom, and thus give rise to the molten condition of metals, or liquid condition of water. Thus, it is the heat which has set the atoms which compose the molecules in motion. The atoms of the solid have absorbed the heat, and the heat which has thus been absorbed has imparted vibratory energy to the atoms, which they did not possess before. Now when a substance is in the liquid state, the atoms of that substance have not only a vibratory motion, but have also a translatory motion, so that they can move in and out among one another. This is proved by the phenomenon of diffusion, where we have the case of two different-coloured liquids, for example, intermingling with each other, which is conclusive evidence of the translatory motion of the atoms in liquids.

Gaseous.—The third state in which matter is found is the gaseous state. In this condition, the particles of matter which form the gas have the greatest possible freedom of movement, and are able to move about with inconceivable velocity. There is abundant evidence to prove that gases consist of particles of matter which are perfectly free, and are able to fly about in all directions. The simplest proof is obtained by mixing two gases together, as, for example, when any gaseous substance is allowed to mix with the air of a room, when we find that the particular gas soon mixes itself thoroughly with all the air in the room. This process of mixing is known as Diffusion, and the lighter a gas is, the more quickly does it diffuse itself. The rate of movement of the various particles is varied, by reason of the encounters which each particle undergoes from time to time. Through experiments made by Joule, he arrived at the conclusion that particles of hydrogen attained a velocity of 6055 feet per second at 0 deg. C., which is a velocity much greater than that of a cannon-ball. In spite of the enormous velocity with which a particle of hydrogen would move, there are such a large number of particles in a single cubic inch of space, that no one particle has an absolutely free path from the one side of the enclosed space to the other. To this constant movement of the individual particles is due the elasticity or pressure of gases. The outward pressure which they exert on any body which encloses the gas is caused by the total effect of the impact of the particles, and is proportional to the sum of their masses multiplied into the square of their velocities. If we halve the enclosed space, then we should double the number of impacts in a given time, so that the number of impacts is inversely as the volume of the gas. This is equivalent to the statement, that the pressure of a gas varies inversely as its volume, which is Boyle and Marriotte's Law.

ART. 37. Matter is Gravitative.—If there is one property which is essentially characteristic to all matter, it is that all matter is gravitative. To this rule there is no exception, as the universal Law of Attraction states that "every particle of matter attracts every other particle." Thus, wherever in the whole universe there is a particle of matter of any kind or sort, whether such matter be solid, liquid, or gaseous, there the force of attraction will be exerted with a force proportionate to the mass of the particle, and inversely as the square of the distance between the attracted particles.

Gravitation, then, is a property which is essentially inherent in matter, and any substance which is termed matter, or fulfils the conditions that govern matter, must be gravitative, whatever other property it may, or may not, possess. Unless this be so, we should have a violation of the universal Law of Gravitation, which would cease at once to be a universal law, for instead of reading "every particle of matter attracts every other particle," we should have to say that "some particles of matter attract some other particles," which would be a violation of that universal law which, through the genius of Newton, has given to the universe an unity from the philosophical standpoint that it did not possess before.

Some matter may, or may not be elastic; it may, or may not be solid, or liquid, or gaseous; but there is this fact regarding matter which is absolutely undeniable, and that is, "All matter is gravitative."

That this is true of each and all kinds of matter has been proved by direct experiment times without number, and the constant application of the law to all forms of matter is a fact observable from the phenomena incidental to every-day life. Astronomical observation teaches us also, that all stars, suns, planets, satellites, and comets are subject to this great Law of Gravitation, as indeed they must be if they are composed of matter. That they are all composed of exactly similar elements of which the earth is composed, has been proved again and again by spectroscopic analysis, which teaches that hydrogen, iron, and calcium, etc., are to be found in distant stars and nebulae, as they are equally to be found in the composition of the earth. Thus throughout the wide universe so far as observation and experiment can teach us, we learn that without any exception, everything that is termed matter is subject to this universal Law of Gravitation.

ART. 38. Matter possesses Density.—Density is that property of matter which decides the weight of a body per unit of volume.

The density of any substance may be shown in several ways. It may denote, first of all, the number of molecules in a given body. Let us take as an illustration, the case of air being forced into a vessel of a given size, say one cubic foot capacity. We will suppose that in such a vessel there are 1,000,000 molecules. If we pump in a quantity of air equal to the amount it contained at first, then it is obvious that we have doubled the number of molecules in the same vessel, and therefore we say we have doubled the density. Not only so, but the weight of the air in the vessel will have been doubled. Looked at from this standpoint, density means the number of molecules in unit volume such as a cubic inch, or cubic centimetre.

Again, as has already been shown in Art. 35, the different elements have different atomic weights. Thus an atom of carbon weighs twelve times as much as an atom of hydrogen, that is to say, there are twelve times as much matter by weight in an atom of carbon as there is in an atom of hydrogen, so that it would take twelve times as many hydrogen atoms to weigh a pound as compared with the number of atoms of carbon. This is only another way of stating that carbon has twelve times the density of hydrogen. If we compare lead and silver with hydrogen in the same way, we find that the density is 206 times and 107 times greater than that of hydrogen.

Thus, it may be seen, that all matter possesses density, and that that density depends partly upon its atomic constitution. If the molecule of matter is composed of atoms whose atomic weights are very large compared with that of hydrogen, as iron, silver, lead and gold, then the molecules will have a much greater density, than a molecule formed of oxygen and hydrogen, i. e. water. This property of the density of matter plays a most important part in the transmission of any kind of wave-motion.

ART. 39. Matter possesses Elasticity.—Matter possesses elasticity. Elasticity is that property of matter which enables all bodies to resume their original shape, when the pressure which has caused the alteration of shape has been removed.

For example, suppose an ivory ball be dropped upon a marble table, or any other hard surface. It will then rebound, and rise almost to the same height from which it was dropped. If the surface upon which it fell was first covered with blacklead, a circular spot of lead will be found on the ivory ball. From this fact, we arrive at the conclusion that when the ball came into contact with the table, at the moment of contact it was flattened, and then owing to its elasticity it rebounded into the air again.

Now the measure of the elasticity of a body is proportionate to the velocity of the wave-motion which it can transmit. A good illustration of the transmission of wave-motion may be shown with a number of ivory bagatelle or billiard balls. If eight or more of these be put in a row, all touching each other, and a single ball be placed about an inch or so away from the others in a straight line with them, then when the single ball is struck with a cue against the other eight, the motion of the single ball is transmitted by each one of the eight successively with such rapidity, that the end ball would be set in motion in a quicker time than a single ball would take to reach the end ball, if it had been free to move along without encountering any opposition.

It is a fact capable of demonstration, that the smaller the particle of matter, the greater will be its vibratory motion. Thus the particles of air are very, very small, and consequently air is found to be very elastic, and allows sound to be transmitted through it with comparatively great velocity, some sounds travelling at the rate of over 1000 feet per second.

A most important factor in determining the propagation of any wave-motion, through a gas or solid, is the relationship of the elasticity of the gas or solid to its density. Suffice to say, that the velocity of any wave-motion is determined by the relation of the elasticity to the density. For example, sound, which is a wave-motion of the air, can not only be transmitted through gaseous bodies as air, but also through liquids and solids. Sound travels faster through solids than through liquids, and faster through liquids than through gases. In liquids, the relation of the elasticity to density is greater than in air, and in solids the relation is greater still. Therefore sound travels much faster in liquids than in gases, and faster in solids than in liquids.

This is the reason why a train can be heard coming if the ear is put to the railway-line, when no indication of its approach is given to the ear by the atmosphere. Some examples of the velocities of sound through different substances are as follows—

Gases O. C. Liquids. Solids. FEET FEET FEET

Air 1090 per sec. Water 4708 per sec. (8 deg. C.). Gold 5717 per sec. Oxygen 1040 " " Alcohol 4218 " " (20 deg. C.). Silver 8553 " "

ART. 40. Matter possesses Inertia.—Inertia is that property of matter, by which matter cannot of itself alter, or change its state of motion, or of rest.

Newton's first law of motion states that a body at rest remains at rest until some force or motion acts upon it. If a stone be dropped from a balloon, the stone does not fall because of any property which it possesses, but because the force of gravity acts upon it. If it were possible to eliminate this force of gravity, then if there were no other force which could act upon the stone, it would remain suspended in space.

The inertia of a body is equal to the mass of that body, or the amount of matter in the body as measured by gravity, so that if a body is halved, its inertia will be halved also, and if doubled, its inertia will be doubled also. As the inertia of matter opposes all kinds of motion, the amount of force required to overcome the inertia of a body is proportionate to its mass. So that if the mass of a body is doubled, then twice the force would be required to move it, while if the body were halved, half the force would suffice to do it.

Inertia is possessed quite as much by a moving body as a body at rest. The definition given points this out, as it states that matter cannot of itself change its state of motion. If a body therefore is in motion, it requires a certain amount of resistance to bring the body to a state of rest, or the loss of an equal amount of energy, by friction or otherwise, equal to the quantity which it absorbed in order for it to be set in motion.

We get numerous examples of this property of the inertia of bodies in our daily experience. Many of the accidents that befall people in various ways are due to this property of the inertia of matter. A cyclist is riding a machine down-hill, and loses control over his machine, with the result that he runs into a wall, and is killed. Now what has happened? The cyclist has participated in the motion of the machine, with the result that when the machine has been suddenly stopped, the body has been thrown forward owing to the momentum it had acquired.

We are constantly being affected by the property of inertia of matter, in tram and train and bus. Whenever any of these are suddenly stopped, or suddenly started, we are thrown either backward or forward, owing to the body either not having acquired the motion of the train, or, having acquired it, is unable to lose its motion as quickly as the train, and is therefore thrown forward.



CHAPTER IV

AETHER IS MATTER

ART. 42. Aether is Matter.—The hypothesis of an Aether which fills all space was made in order that scientists might be able to account for certain phenomena of Light, which otherwise were difficult to account for. Its existence is demanded not only for the phenomena of Light, and Heat, but, in view of the comparatively recent researches of Hertz on "Electric Waves," of Electricity also.

The Aetherial Medium is generally assumed to be that fundamental medium, by means of which possibly all the properties of matter, and all the phenomena of motion of the universe are to be explained. Light and Heat have been proved to be due to the periodic wave-motion of this universal Aether, while from the investigations and researches of such men as Clerk Maxwell, Poynting, Thompson and Hertz, it has been proved that electro-magnetic phenomena are due to this same medium.

Several different forms of Aether have been postulated by various philosophers from time to time, but the only Aether that has survived, is that which was first conceived by Huyghens to explain the phenomena of Light, though it was Thomas Young who finally succeeded in placing the conception of the Aether on a sound basis. Each discovery of science has only strengthened the hypothesis and existence of the Aether, the latest discovery, that of wireless telegraphy so successfully developed by Signor Marconi, being attributed to the electro-magnetic properties of this self-same Aether.

It has already been pointed out that Newton endeavoured to account for Gravitation by the pressure of the Aether. If, therefore, Gravitation be really due to this universal medium it becomes necessary to ask ourselves, What are the properties and characteristic qualities of this wonderful medium? What then is Aether, and what its properties?

It has already been pointed out in Art. 29 that Aether is matter. Such an assumption is strictly in accordance with the Rules of Philosophy, quoted in Chap. I.

Not only is this hypothesis a simple one, but it is also in accord with all our experience and observation.

It is a simple supposition, because, unless Aether is assumed to be matter, then, instead of the universe being composed of two classes of things, matter and motion, we have to add a third class, which we call Aether. It can be readily seen, that by the introduction of a third class into the composition of the universe, such an addition, instead of simplifying the constitution of the universe, adds greater complexity to the same.

By accepting the hypothesis that Aether is matter, we do away with the third class of essentials in the universe, and so reduce the number to two classes. If we could go one step further, and prove that instead of there being two classes of things in the universe, there was only one group, and show that all material things, and all phenomena could come under the head of either matter, or motion, then we should have reduced the universe to the simplest conception possible. As, however, it is not possible, at least in our present state of knowledge, for us to come to this fundamental and simple hypothesis of unity for the entire universe, we must accept the next simpler solution, and affirm that the universe is composed of two classes of things, viz. matter and motion, and this as I have already shown is a simpler classification than by putting Aether into a class by itself, and therefore is in accord with our first Rule of Philosophy.

Again, it is entirely in accord with our second Rule of Philosophy, as it in no way violates the results of experiment, experience, or observation. Look where we will, or at what we will, whatever we see, touch, taste, or smell is termed matter. The burning sun, the glowing star, the flying meteor, the glowing comet, the earth, our own island home, the towering rock, the wide ocean, the running river, the green trees of the forest, the tiny insect, the lordly elephant, all animals, plants, and our own physical body, all are composed of matter, either in solid, liquid or gaseous form. Therefore when we affirm that Aether is matter, the affirmation is strictly in accordance with the elementary principles of Philosophy, and in no way violates their rules or laws. To affirm that Aether is not matter, is to affirm something contrary to all experience, unless it be affirmed that Aether is motion, for which assumption the evidence is not nearly so strong or conclusive as that it is matter. Therefore the objector to this assumption is himself unphilosophical, in that he postulates or supposes that the Aether is a medium, with qualities which lie altogether outside the range of our experience and observation.

There is a growing conviction in the minds of scientific men, that Aether belongs to that group of things which we describe by the term matter. Lord Kelvin in giving an address to the British Association, 1901, on "Clustering of Gravitational Matter in any part of the Universe," said: "We are all convinced with our President (Professor Rucker) that Aether is Matter. Aether we relegate to a distinct species of matter which has inertia, rigidity, elasticity, compressibility, but not heaviness."

Dr. Larmor in Aether and Matter writes: "Matter must be constituted of isolated portions, each of which is of necessity a permanent nucleus belonging to the Aether, of some such type as is represented for example by a minute vortex ring in a perfect fluid."

Faraday in relation to this subject writes (Exp. Res., vol. ii.): "The view now stated of the composition of matter would seem to involve the conclusion that matter fills all space, or at least all space to which Gravitation extends, including the sun and its system, for Gravitation is a property of matter dependable on a certain Force, and it is this Force which constitutes matter." As the Aether fills all space, including the solar system, therefore, according to Faraday, "Aether must also be Matter."

By the hypothesis that Aether is matter, with all the properties that such a hypothesis logically gives to Aether, I venture to premise that the third Rule of Philosophy will be fulfilled, and that there is no phenomenon of the astronomical world, and no part of the universal Law of Gravitation which such a hypothesis will fail to account for on a satisfactory physical basis. For the first time a physical explanation will be given to Newton's Laws of Motion, at least to those laws which are strictly in accordance with the first and second Rules of Philosophy. For the first time a physical conception will be given to all Kepler's Laws, and what the mathematical Laws of Gravitation have done to Kepler's Laws, in giving them a mathematical basis, the simple hypothesis that Aether is matter, with all that is logically involved therein, will do for the same laws from the physical standpoint. For the first time a physical conception will be given to the Centrifugal and Centripetal Forces, which are the complement and the counterpart of each other, that physical conception being the outcome of the same hypothesis that Aether is matter.

In addition to this, light is thrown upon such problems as are referred to by Lord Kelvin (Phil. Mag., July 1902) in his paper on "Clouds on the Undulatory Theory of Light," and further light is given to some theories of Electricity advanced by such men as Faraday, Clerk Maxwell, and Professor Thompson. I venture to think, therefore, that the hypothesis advanced, and the conception put forward that Aether is matter, is philosophically correct, and is warranted by the results that arise out of such a hypothesis.

It may be thought by some that the hypothesis that I have advanced is already conceded, and that the fact that Aether is matter is already admitted by scientists and advanced thinkers generally. But such an idea is only partly correct. It is already admitted by some of our most advanced scientists that Aether is matter, but that admission is only carried partially to its logical conclusion.

Lord Kelvin in an address to the British Association, 1901, gave utterance to the following remarks on the relation of Aether to Matter: "We are convinced with our President (Professor Rucker) that Aether is Matter, but we are forced to say that the properties of Matter are not to be looked for in Aether, as generally known to us by action resulting from force between atoms of Matter and atoms of Aether. Here I am ILLOGICAL when I say between Matter and Aether, as if Aether were not Matter. Aether we relegate to a distinct species of Matter which has inertia, rigidity, elasticity, compressibility, but NOT HEAVINESS."

From a quotation of this kind, which is from the lips of one of the keenest intellects of the present time, I think I am justified when I make the statement, that it is not conceded that Aether is matter, with all that that concession logically involves. Because, as Lord Kelvin points out, though it is admitted that Aether is matter, yet that admission is only a qualified admission, and not one which carries with it all the properties that essentially belong to matter, or an admission which includes the fact that Aether is gravitative, that is, subject to Gravitation. To be strictly logical and philosophical, in the statement that Aether is matter, it must be conceded not only that Aether is subject to such properties as elasticity, inertia, and compressibility, but that it is also gravitative or possesses weight. For either Aether is matter, or it is not matter.

It cannot be both at one and the same time. Such a conception is altogether opposed to that simplicity which is the chief characteristic of Nature as pointed out by Newton.

If therefore Aether be matter, then, to be strictly logical and philosophical, it must be conceded that Aether is gravitative, as well as having the other properties of matter, as elasticity and inertia, etc. Unless this is conceded, then we have the anomaly in Nature of matter, which is not matter, because it violates the very principles which above all others decide what is matter, viz., "That every particle of matter attracts every other particle," etc., that is, that it is gravitative. Thus by supposing that the Aether is matter, and yet not being gravitative, all the Rules of Philosophy are violated, as such a hypothesis is opposed to both the first and second Rules of Philosophy, and is contrary to all observation and experience. If Aether therefore be matter, as is conceded by the most advanced thinkers of the time, then it follows that the only logical and philosophical conclusion that can be arrived at is, that it is also subject to those properties which are the chief characteristics of all matter. These properties may be classified as follows: atomicity, gravitation, density, elasticity, inertia, and compressibility.

ART. 43. Aether is Universal.—Young in his first Hypothesis on the Aether medium states that, "A Luminiferous Aether pervades the Universe rare and elastic in a high degree" (Phil. Tran., 1802).

As Young points out, this invisible and elastic Aether fills all space and floods the universe at large. In it suns blaze, stars shine, worlds and planets roll, meteors flash, and comets rush in their mysterious flight. In it all material and physical things exist, for it is to them not only the primary medium of their existence, but, just as the infinite and ever-active energy of the Divine is to the universe in its entirety and fulness, the exciting and stimulating spirit of its energies and powers, so this aetherial ocean is to the material and physical universe, the exciting and stimulating medium of all its activities, energies, and powers; and without which, though all material and physical things were endowed with the varied capacities of their kind or life, yet they could neither exert nor exercise them, nor even exhibit the simple activity of motion. Hence everywhere, where material and physical things are, there, as the medium of their existence and energy, the Aether is; and where the Aether is not, no material or physical thing is, or can be. That the Aether is universal is proved by the phenomena of light. Light-waves have a velocity of about 186,000 miles per second. Now the distance of the sun from the earth is about 92,000,000 of miles, so that light takes about eight minutes and a half to travel from the sun to the earth.

A ray of light from the nearest fixed star takes about three and a half years to reach the earth, while there are some stars so far away that astronomers tell us, that though light travels with so great a velocity, yet it would take several thousand years to reach the earth. This fact implies that throughout boundless space there is to be found this aetherial medium. Thus interplanetary and interstellar space is not empty, but is filled with this ever-present, all-pervading Aether; and not only so, but every particle of matter in the universe is surrounded by this universal Aether, which forms the exciting and stimulating medium of all the activities, energies, and motions of all Matter. Thus the Aether is both universal and infinite in its extent.

Clerk Maxwell, in his paper on "Action at a Distance" (Collected Works, by Niven), with reference to the universality of the Aether, writes: "The vast interplanetary and interstellar regions will no longer be regarded as waste places in the universe, which the Creator has not seen fit to fill with the symbols of the manifold order of His Kingdom. We shall find them to be full of this wonderful medium, so full, that no human power can remove it from the smallest portion of space, or produce the slightest flaw in its infinite continuity. It extends unbroken from star to star, and when a molecule of hydrogen vibrates in the Dog Star, the medium receives the impulses of those vibrations, and transmits them to distant worlds. But the medium has other functions besides bearing light from world to world, and giving evidence of the absolute unity of the material system of the universe. Its minute parts may have rotatory as well as vibratory motions, and the axes of rotation form those lines of magnetic force which extend in unbroken continuity into regions which no eye has seen, and which, by their action on our magnets, are telling us in language not yet interpreted what is going on in the hidden world from century to century." Now I premise, that in the theory of the Aether to be submitted in this work, the physical interpretation of this statement of Maxwell's will receive its literal fulfilment.

ART. 44. Aether is Atomic.—If there is one fundamental truth which is applicable to all matter, it is, that all matter is atomic.

Professor Rucker, in his Presidential Address to the British Association of 1901, in dealing with this question, said: "The believer in the atomic theory asserts that matter exists in a particular state, that it consists of parts which are separate and distinct from one another, and as such are capable of independent movement. It is certain that matter consists of discrete parts in a state of motion, which can penetrate into spaces between the corresponding parts of surrounding bodies. Every great advance in chemical knowledge during the last ninety years finds its interpretation in Dalton's Atomic Theory."

From such an authority as this, and from the facts which he gave in his dealing with the question, we are bound to admit that all matter is atomic. That being granted, when the statement is made, therefore, that Aether is matter, the only logical conclusion that can be arrived at, with reference to the question of the atomicity of the Aether, is, that Aether is also atomic. Unless this be conceded, we have the first and second rules of our Philosophy violated, as an atomless Aether is opposed to that simplicity of conception, which is an essential requirement of all hypotheses, and is moreover contrary to that presumptive evidence gathered from observation and experiment, which teaches us that all matter is atomic. If it be argued, that it is impossible to decide upon a question as to the atomicity of the Aether, my reply is that the same argument may reasonably be applied to all matter. But, as Professor Rucker stated, all the evidence on matter points out and supports the theory of its atomicity, and, therefore, the only logical and philosophical conclusion is, that Aether is atomic also. Again, it may be suggested that we cannot see or touch an atom of Aether, and that it is not only invisible, but apparently incapable of being made sensible to our senses. In reply to that, as I have already shown in Art. 31, that objection can be equally used against an atom of hydrogen, or an atom of oxygen. Does any one doubt the existence of the hydrogen atom or the atom of oxygen, because it is invisible to the sense of sight, or cannot be revealed to the limited sense of touch? Certainly not! By the same reasoning, it is just as illogical to deny the existence of an atom of Aether because it cannot be seen or felt, as it is to deny the existence of an atom of hydrogen or oxygen. An atom of Aether reveals itself to the senses in the same way that an atom of hydrogen or oxygen does, that is, by the force or energy which it exerts. Its vibrations can be manifested to the body in the form of heat, while the undulatory motion which the aetherial atoms transmit in the form of light, reveal the presence of the aetherial atom to the sense of sight. The question at once arises as to what constitutes an aetherial atom, what are its properties and motions?

Now, in order for us to enter successfully into this speculative region, it is essential that we should, as far as possible, conform to the Rules of Philosophy, and endeavour to gain some conception of an aetherial atom from the results of experience and observation. In doing this, we are at once confronted with the difficulty, that no one has ever seen an atom, or analyzed the properties of one. Actual experiment has revealed nothing absolutely certain as to the ultimate character of an atom, and if this be true of the atoms of matter, then it must also be true of an aetherial atom. It would seem at first, therefore, that we have no results of experiment, or observation, by which we may be guided in formulating a right conception as to the constitution of an aetherial atom, and therefore we are thrown simply into the regions of speculation as to its constitution and properties.

But I venture to suggest, that there is a method which is strictly philosophical in its application, by which we may possibly arrive at a clear conception of an aetherial atom. All great discoveries of science have been the outcome of applying the principle, that what is true of the visible and seen, is true of the invisible and unseen; that what is true of the known, is true of the unknown; that the principles and laws which govern the small also govern the large and the great. It was thus that Newton discovered his great Law of Gravitation, as he was able from the falling of an apple, to rise to the application of the same principle to our satellite the moon, and this led him on to the discovery of the Law of Gravitation.

If, therefore, in Philosophy, the laws governing the small things are also applicable to the great things, then the converse equally holds good, that the laws governing great things are the reflex of the laws which govern the small things. For example, the laws which govern the light and heat of the sun are the same which govern the light and heat of a candle or a glow-worm; and the laws which govern a planet or world are the same as those which govern an atom. Thus a planet or world, which is simply an agglomeration of atoms, may reveal to us in its motions and laws, what are the motions and laws which govern the atomic world.

In looking at the properties and motions of a planet, therefore, as our earth for example, we find that a planet is a sphere, or more correctly an oblate spheroid; that the earth or planet is a magnet possessing polarity, having a north and south pole; that it has rotation on an axis, in addition to translation in an orbit, and that it is subject to the universal Law of Gravitation.

If, therefore, it holds good in Philosophy, that the small things are the index to the greater, and that the laws governing the small things also govern the greater, then the converse holds good, that what is true of the large is true of the small, and that the laws governing the great also govern the small.

So that gathering up those chief properties of the earth to which I have already referred, and applying them to an aetherial atom, or any other atom if necessary, we arrive at the conclusion that an atom must be spherical in shape, must possess rotation, and must have an orbit, must possess polarity, and also be subject to the universal Law of Gravitation.

Here, then, we have given to us certain data by which we are enabled to form our conception of an atom, aetherial or otherwise. The question arises, whether, among the forms of atoms which have been devised by scientists, any of the atoms so conceived fulfil all, or nearly all of these requirements. We have Boscovitch's Atom, the Hard Atom of Lucretius, and the more recent conception of the Vortex Atom of Lord Kelvin. Of all the hypotheses in regard to the ultimate nature and constitution of an atom, the Vortex Theory probably is the one which offers to the mind the simplest conception of an aetherial atom.

The Vortex Ring Atom, however, which has been so fully developed by Lord Kelvin, hardly fulfils all the requirements of an aetherial atom. In the first place it is not spherical in shape, and I hold that to be one of the fundamental bases of the aetherial atom. Then, in the next place it does not, so far as I can read, possess polarity; that is, it does not possess a north and south pole, through being a magnet in the same way as the earth is a magnet. We must therefore look for a modification of the vortex ring to discover the constitution of our aetherial atom, and I venture to think that such a modification is to be found in Professor Hill's conception of a Spherical Vortex Atom (Phil. Trans., 1894).

In the conception there put forward, and mathematically worked out, Professor Hill showed that his spherical vortex atom possessed similar properties and characteristics to the vortex rings of Lord Kelvin. So that the spherical vortex atom would possess rotation on an axis, and it would be a magnet, as I shall prove later on, because it rotates in an electro-magnetic medium. It would possess elasticity, compressibility, inertia, and, further, would possess a certain amount of mass. That mass might be infinitely small, but nevertheless it would possess mass of an infinitesimal order.

Further, if we are to be strictly correct, in our analogy between the earth and the aetherial atom, its polar diameter must be shorter than its equatorial diameter, as that is one of the facts observable regarding the shape of our earth, so that the shape of the aetherial atom will not be strictly spherical, but its actual shape would be that of an oblate spheroid, being flatter at the poles, and bulging out in the equatorial regions.

This exact analogy between the earth and an aetherial atom may not at present seem of very great importance, but its importance will be seen later on, when we come to deal with the phenomena of heat, light, and electricity.

Here, then, is our conception of an aetherial atom in the rough, based not upon any imaginative hypothesis, but rather upon that strict conformity to observation and experience, which is the very groundwork of all true Philosophy.

For, after all, what is the earth but an atom on a large scale? In comparison with illimitable space, with its infinite distances, that can alone be measured by the velocity of light, our own earth is but a speck of dust, a very atom that helps to make up the universe, and, as such, should teach us the shape and properties of other atoms of which the same universe is composed.

We have therefore to conceive of the all-space-pervading Aether as being composed of infinitesimal portions of Aether, which are nearly spherical in shape, and ever in a state of rotation; this state of rotation differentiating the atom of Aether from the free Aether, if such an entity exists. So that an atom of Aether would simply be an infinitesimal portion of the Aether in a state of rotation.

If, by any means, we could stop the rotation, we should at once destroy the atom, in the same way that the smoke vortex ring would cease to be a ring, if its rotation were stopped. The cessation of the rotation I, however, believe to be impossible. So that even in the ultimate atom of that universal medium the Aether, we have an illustration of the combination of those two forms which are inseparably connected throughout the whole universe, viz. matter and motion, and it is the combination of these two that gives to the aetherial atom its form, and its very existence, without which it has no life, and ceases to exist.

It may be necessary in the development of this work as we proceed, to slightly modify our conception of the aetherial atom, but that modification will rather be of a constructive character, than a destructive one. There may also be certain objections to meet and explain away when we deal with the phenomena of light, heat, and electricity, and Gravitation, and the part which the aetherial atom plays in those phenomena, but these objections I hope to meet and answer as they arise.

The atomicity of the Aether has already been suggested by such scientists as Clerk Maxwell, Lord Kelvin, Dr. Larmor, and Professors Lodge and J. J. Thompson. Clerk Maxwell, in an article on "Action at a Distance,"[3] referring to the atomicity of the Aether, writes: "Its minute parts may have rotatory as well as vibratory motions, and the axes of rotation may form those lines of magnetic force which extend in unbroken continuity into regions which no eye has seen." I premise that I will conclusively prove that this statement finds its literal fulfilment in the theory of the Aether that will be developed in this work.

Lord Kelvin, in several articles on "Vortex Motion" in the Philosophical Magazines of recent years, has mathematically dealt with the Aether from the atomic standpoint, and has endeavoured to prove that the Aether medium is composed of vortex rings, but he was unable to come to any satisfactory conclusion. With the theory that Aether is matter, and therefore possesses mass, his conception is now brought within the range of physical explanation, as well as mathematical calculation.

Dr. Larmor, in his Aether and Matter, has successfully applied the principle of the atomicity to the Aether, on what is termed the "Electron" basis. He states that an electron is nothing more or less than "a point singularity in the electro-dynamic and optical Aether." So that our aetherial atom is practically synonymous with Dr. Larmor's electron. Again, Dr. Larmor, in the same work, states that "the atomicity of electricity is coming within the scope of direct experiment."[4] But Professor Lodge, in his Modern Views of Electricity, states that "the Aether is composed of positive and negative electricity, the combination of these two forming the Aether medium."[5] Now, if the Aether is composed of positive and negative electricity, and the atomicity of electricity is coming within the scope of direct experiment, it follows as a matter of necessity that the atomicity of Aether and the atomicity of electricity are one and the same, and therefore the atomicity of Aether is coming within the scope of direct experiment. Professor J. J. Thompson, who has also attacked the problem of the atomicity of electricity, speaks of "corpuscles" which are the actual carriers of the positive and negative electricity, in the atoms of the various elements. These corpuscles therefore indicate the fact that electricity has an atomic basis.

Now if there is any such identity between Aether and electricity, as there undoubtedly is, and electricity has an atomic basis, then the atomicity of the Aether follows as a matter of course, otherwise we shall have a medium composed of atoms which is itself not atomic, which conclusion is absurd and therefore unphilosophical. So that the most recent researches into electricity confirm and establish the atomicity of the Aether.

[Footnote 3: Collected Works, by Niven.]

[Footnote 4: Preface to Aether and Matter.]

[Footnote 5: Page 348.]

ART. 45. Aether is Gravitative.—Young, in the Philosophical Trans. of 1802, in regard to this question, states in his Fourth Hypothesis: "All material bodies have an attraction for the aetherial medium, by means of which it is accumulated within their substance, and for a small distance around them, in a state of greater density, but not greater elasticity." He adds that "this fourth hypothesis is opposed to that of Newton's."

Scientific research has justified the conception of his first three hypotheses with respect to the universality, elasticity and vibrations of the aetherial medium, but up to the present I am not aware that science has accepted his fourth hypothesis.

I propose to show how, from a strictly philosophical and logical standpoint, his fourth hypothesis is just as true as his first three hypotheses, and that it henceforth passes out of the realm of the hypothetical into the realms of fact and science, not only by philosophical reasoning, but by actual experiment made by some of the most advanced scientists of the present time.

Let us consider the question first from the standpoint of the Rules of Philosophy. Our first Rule of Philosophy states, that any hypothesis must be simple in connection. Now I put it to any intelligent man, and ask him which is the simpler conception of Aether? To affirm that Aether is matter, and therefore subject to the properties of matter, as elasticity, density, inertia and Gravitation, or to affirm that Aether is matter, but while it is subject to some of the properties of matter, as elasticity, density and inertia, it is not subject to the very property which of all properties is the most fundamental, viz. Gravitation. There can, in my opinion, only be one answer to the question, so that, when we affirm that Aether is matter, we are compelled to affirm, in order to conform to the first Rule of Philosophy, that it is gravitative also. Faraday was also of the opinion that Aether was subject to the Law of Gravity, for, writing in Experimental Researches, he states: "The view now stated of the constitution of matter, would seem to involve the conclusion, that matter fills all space, or at least all space to which Gravitation extends, INCLUDING THE SUN AND ITS SYSTEM. For Gravitation is a property of matter, dependable on a certain force, and it is this force which constitutes matter."

Let us also test the question by our second Rule of Philosophy, and we shall find greater evidence still for the statement that Aether is gravitative. What do experience and observation teach us with reference to matter? As we have already seen (Art. 37), if there is one truth that they teach us regarding matter, it is that it is gravitative.

There is not the slightest evidence throughout the universe, as far as our observation can lead us to form an opinion, that there is any kind of matter which is not subject to the Law of Gravitation. Therefore to assume that Aether is matter, and yet not to assume that it is also subject to Gravitation, is to assume that which is directly opposed to the most fundamental principle of all philosophical teaching and scientific research. If Aether be matter, therefore, and yet is not gravitative, we shall have an anomaly in an otherwise universal law, as we shall have some kind of matter which fails to come within the scope of the universal Law of Gravitation.