So that electric potential agrees with our conception of a gravitative Aether in that, being gravitative, it is denser in those parts nearest to the attracting body than farther away, and as the elasticity or pressure is proportionate to the density (Art. 47), therefore we learn that the electric potential of the Aether, and the thermal condition of the Aether, if I may use such a term, both agree and coincide with the density and elasticity of the Aether.
Any equipotential surface which represents a particular aetherial density, would also correspond with a particular elasticity or pressure of the Aether, while it would further correspond with a particular temperature, if such a term is applicable to the Aether.
Equipotential Surfaces.—The fact that in an electric field there are different points at different potentials, leads us to the truth that in an electric field there are also equipotential surfaces; that is to say, there are surfaces where the electric density or the aetherial density are equal at all points on such a surface. If, for example, E be an electrified body (Fig. 9), and A A', B B', represent equipotential surfaces around the body, then all the points on A A' would be of equal potential—that is, of equal energy, or pressure.
We have to remember that A A', B B', are sections of a sphere, so that when the body as E is a sphere, then the equipotential surfaces are spheres also. This agrees with Art. 77, in which we saw that the pressure around any body due to aetherial density also possessed equipotential surfaces.
It could equally be shown that there were equipotential surfaces so far as the phenomena of heat and light are concerned, as these also are subject to the same laws. Having now very briefly considered the meaning of the Electric Field, Electric Potential, Electric Density, and Equipotential Surfaces, we are now in a position to apply these facts to our solar system, at least as far as the sun is concerned.
In the foregoing Art. we arrived at the conclusion that the sun was an electrified body, therefore, in accordance with all experiment and observation, it, too, must have an electric field. Not only must it have an electric field; but that field must possess different potentials, possessing a higher potential the nearer the field gets to the sun, and a lower potential the farther away the field is.
Further, around the sun there must also exist not imaginary but real physical lines of force which indicate the electric and magnetic forces, and which are made real by the atomic character of the Aether that surrounds it; and those lines of force would be closer together the nearer they got to the sun on account of the electric density of the electric Aether, which coincides with the density of the Aether from the gravitative standpoint. There would also be aetherial equipotential spheres, or rather oblate spheroids around the sun, as the sun is not strictly a sphere, its polar diameter being less than its equatorial diameter.
Let us therefore endeavour to picture the sun under these conditions as the centre of our solar system. Let S be the sun (Fig. 10), and the lines A A', B B', C C', etc. represent Equipotential Surfaces, Fig. 11 being a vertical section and Fig. 10 being an equatorial section. In Fig. 11 the sections of the equipotential surfaces would be vertical, while in Fig. 10 the sections of the equipotential surfaces would be horizontal, while the electric lines of force would be radial, as all electric radiations take place in straight lines, as we shall see was proved by Hertz, later on. We will suppose that the sun is stationary, as the question of the movement of the sun, both axially and through space, will be considered in a subsequent article.
Then the question arises, How far does the sun's electric field extend? That is rather a difficult question to answer, but the correct answer would be, "As far as the sun's light extends, so far does the sun's electric field extend." From the electro-magnetic theory of light we know that wherever there are light waves, there are electro-magnetic waves, though at the present moment we are only dealing with the electric aspect of those waves.
We know that the aetherial light waves reach at least as far as Neptune, a distance of 2,750,000,000 miles, therefore we know that the sun's electric field must also extend to that distance. How much further in space it extends we cannot tell, because the data on which to form a basis is inadequate.
Thus we learn that the sun's electric field extends east and west for that enormous distance, but we cannot say that it extends the same distance north and south. Now why is that? The first reason I should give is the well-known experiment of a revolving body, by which we learn that when a body is revolving, as the sun for example, the atmosphere around it would seek to extend itself east and west, owing to the Centrifugal Force so called. But a better reason than that will be found from an analogy of a magnetized body. Faraday has shown in his drawings illustrating lines of force, that if a spherical body is magnetized, the magnetic lines of force extend in circles east and west, but go out into space in almost straight lines north, and south as the preceding figure shows.
Therefore, accepting Faraday's experiment as the basis for our conception of the magnetic lines of force in the sun's electric field, we come to the conclusion that the electric field around the sun extends east and west, while the lines of force, north and south, are more or less radial into space as depicted in the figure.
Throughout the whole of the field, the electric potential, at different distances from the sun, would differ in accordance with all experiment and observation. The greatest electric potential would therefore be nearest the sun's surface, and would be greatest in the equatorial regions of the sun, in accordance with a well-known rule which determines electric density and electric potential on conductors.
As we proceed from the sun's surface east and west into space, we should pass equipotential surfaces of different potentials. Thus the pressure on every point of equipotential surfaces would be regulated by the electric density of the Aether, which would coincide with the actual aetherial density at that point; and as the aetherial density is the measure of its elasticity or pressure, so the electric potential would correspond with the elasticity or pressure at the same point.
Thus it is possible to map out the electric field east and west by ever-increasing and widening circles which would be at lower potential the further they receded from the sun. So that by carrying out the electro-magnetic theory of light to its logical conclusion, we are able to bring the whole of the solar system into line with electric phenomena; and, as we proceed, we shall see that all other facts relating to electricity, and magnetism also, are equally as applicable thereto, otherwise this theory of light must fall to the ground.
That this conception of the universal Aether in its application to solar space is not extravagant may be proved from the writings of Prof. Tyndall and Clerk Maxwell. Tyndall, writing on the subject of Faraday's Lines of Force, says: "The aspect of these curves so fascinated Faraday that the greater part of his intellectual life was devoted to pondering over them. He invested the space through which they run with a kind of materiality, and the probability is that the progress of science, by connecting the phenomena of magnetism with the luminiferous Aether, will prove these 'Lines of Force,' as Faraday loved to call them, to represent a condition of this mysterious substratum of all radiant action."
While Clerk Maxwell, writing on "Action at a Distance," says: "These Lines of Force must not be regarded as mere mathematical abstractions. They are the directions in which the medium is exerting tension like that of a rope, or rather like that of our own muscles." I therefore premise, that both these statements will find a literal fulfilment in the conception of the Aether advanced and perfected in this work.
[Footnote 25: Phil. Mag., 1861.]
[Footnote 26: Tyndall on Light.]
[Footnote 27: Collected Papers, by Niven.]
ART. 81. Aether and Induction.—We have seen in the preceding Arts. that the sun is an electrified body, possessing an electric field, which field possesses different intensities at different distances from its surfaces.
If such be the case, the question at once confronts us, as to what is the effect of such an electrified body with its electric field upon all the planets which revolve around it; for, if its electric field extends as far as Neptune, then all the planets and meteors, that revolve around the sun, must revolve in the sun's electric field.
Such a question can best be answered from the consideration of experiments and theories advanced first by Faraday, who gave to the world his theory of Induction, which we shall now consider.
Let A be an electrified body (Fig. 13), and C be a body not electrified, but situated within the electric field of A. Then it can be experimentally proved, that C will also become an electrified body by induction. As is well known, there are two kinds of electricity, Positive and Negative. We will suppose A to be charged with positive electricity. Then it can be proved that C will also be charged with negative electricity on the half nearest to A, while the other half will be charged with positive electricity.
Now how has this result been brought about? According to Faraday's theory the particles of air, the dielectric, between A and C play a most important part in the process. As a matter of fact, each atom or particle of air is polarized, as the process of separating the two kinds of electricity is termed, so that every atom has one half of it covered with positive electricity, and the other half with negative electricity.
For example, let A and C be the same brass balls with the particles of air between them, A being the positively charged ball and C the unelectrified ball, the shaded parts representing positive electricity and the unshaded parts negative electricity.
Then A will act inductively on the unelectrified ball C through the medium of the particles of air d, e, f, g, h. The electrified ball A will act first on the layer of particles next to it, attracting their negative electricity and repelling the positive according to the well-known law that "Unlike electricities attract, like electricities repel each other."
The positive electricity in the first layer then acts in the particles of the next layer in the same way, and thus the inductive action is transmitted through the particles, from layer to layer, until we come to the last layer of particles next to the ball C.
As the half of each atom or particle nearest to C is positively electrified, then the half of the ball C nearest to the layer becomes negatively electrified, while the half further away is positively electrified. Thus we say that C has become electrified by induction through the polarization of the particles of air which lie between the two bodies. Faraday on this point says: "Thus induction appears to be essentially an action of contiguous particles, through the intermediations of which the Electric Force, originating at a certain place, is propagated or sustained at a distance, appearing there as a Force of the same kind exactly equal in amount, but opposite in its direction and tendencies."
While again he states: "Induction appears to consist in a certain polarized state of particles into which they are thrown by the electrified body sustaining the action, the particles assuming positive and negative parts which are symmetrically the lines of Inductive Force." Thus in the case of any electrified body, acting on an unelectrified body at a distance, it has to be definitely understood that the action at a distance is alone communicated and propagated by the dielectric or medium which exists between the two bodies. Though in the case of Gravitation it has been mathematically assumed, that action at a distance is possible, yet experimentally and physically such an assumption is philosophically incorrect, as all experience and experiment go to prove that there is no such thing as action at a distance manifested, except such action is propagated through the intervening medium, as stated and proved by Faraday.
In order to bring Gravitation, therefore, into line with our experience, it will have to be demonstrated that it, too, is the result of the action of the intervening medium, that is, the Aether, which is a result we are being led up to.
We have already seen that the sun is an electrified body, possessing an electric field, and as all electrified bodies can act on other bodies in their field inductively, then a similar result should happen in the solar system, that happens in any electrical experiment on induction, with the result that all the planets should become electrified bodies by induction, such action taking place, as Faraday points out, through the medium which divides the sun and the planets, that is, the Aether.
Of course with a frictionless and non-atomic Aether such a result would be an impossibility, but with our conception of an atomic and gravitative Aether the result is now attainable. We have therefore to think of the sun, the centre of the solar system, being an electrified body, and for illustration we will suppose it to be a positively charged body.
All around the sun is the atomic Aether, which is polarized in the same way that the particles of air were polarized; that is, the two kinds of electricities in the aetherial atom are separated, the negative being on that side nearest to the sun, and the positive on the side further away. In this way the whole aetherial medium would be polarized, and any body in the field would be electrified by induction, with the result that the side nearest the sun would be negatively charged, and the opposite side positively charged.
Thus let S (Figs. 10 and 11) be the sun, and the circles represent equipotential surfaces, then one half of every surface would be negatively electrified and the other half positively electrified, that is, assuming the sun to be a positively electrified body.
If M represents Mercury, V represents Venus, and E represents the Earth (Fig. 10), then it can readily be seen that all these would be negatively electrified on the side facing the sun; and, as they rotate on their axes, each part of the planet would be positively and negatively electrified once each day.
We are assuming that the medium is at rest, but according to our conception in Art. 44, all the aetherial atoms are in rotation on their axes, in the same way that the earth rotates on its axis, so that each of these aetherial atoms would present different parts of its surface to the sun as it rotates on its axis; but, as that does not affect the principle of induction, such a fact need not now be fully considered.
Let us now ask, What is the result of all the planets becoming electrified bodies in the same way that the sun is an electrified body? Arguing from experience, we come to the conclusion that each planet must also possess its electric field, which also must have its lines of force, its different potentials at different distances, and its equipotential surfaces. So that Mercury, Venus, the Earth, Mars, Jupiter, Saturn, Uranus, and Neptune all have their electric fields, with their own lines of force, and with their equipotential surfaces.
If we carry the analogy further still, then it can also be proved that the Earth, and those planets which have moons or satellites, also act inductively on their satellites, with the result that they too become electrified bodies, with their own smaller electric fields and lines of force. This may seem at first sight a little confusing, but the confusion will gradually disappear if we will look at it carefully for a moment or two. Let us endeavour to picture the solar system from this new standpoint, and map out the equipotential surfaces, which this idea suggests. Let S represent the sun (Fig. 14), the initials of all the planets and satellites representing the various planets; then we get the following plan of the solar system with the various equipotential surfaces shown by the circular lines.
We are now supposed to be looking down on all the solar system from above it, so to speak, so that we should be looking at what we call the North Poles of the sun and planets.
Thus we see that the equipotential surfaces around the sun are huge circles which stretch out as far as Neptune or even beyond, but within those circles we find each of the planets revolving round the sun, each with its own equipotential spheres, which are circles also, while around the various planets are the satellites, from the moon of our Earth, to the two satellites of Mars, five of Jupiter, eight of Saturn, each with its own lines of force and electric fields.
Of course we must not forget that all these revolve round the sun, and the question may suggest itself to the reader's mind, if such a result is possible. I shall prove later on, that according to Maxwell such an event is possible, but at present we will consider them stationary.
Now let us see how such a conception compares with our hypothesis of a gravitative Aether. If Aether be gravitative, then the sun must have an attraction for the Aether, and its aetherial field would stretch out into space as far as Neptune at least.
So that it can readily be seen that the aetherial field of the sun's attractive power coincides with the electric field which the sun possesses as an electrified body. Again, if Aether be gravitative, then all the planets must also have an aetherial field, which will be co-extensive with their electric field also. The same principle applies to each of the satellites, with the result that they too will possess an aetherial field which will be equal in extent and limit to their electric field.
As the satellites revolve around their primary planet taking their electric fields with them, so the planets with their associated satellites revolve around the sun taking their electric and aetherial fields with them. Thus we get a glimpse, though at this point very shadowy and indistinct, of those motions of the universal Aether, which help to constitute the harmony, beauty, and order of the universe. We have seen, therefore, that as the sun is an electrified body, so all the planets and satellites are electrified bodies also, each possessing its own field, with all that such a field implies.
We shall find that such a conception is borne out by experience and observation, when we come to deal with the Earth as a magnet; because we shall afterwards learn that the Earth is an electro-magnet, possessing its magnetic field, which is co-existent and equipollent with its electric field.
[Footnote 28: Exp. Res., 1297, 1298.]
[Footnote 29: Par. 1298.]
ART. 82. Energy of the Field.—We have seen in Art. 79 that every electrified body has an electric field. We have further learned, in carrying the electro-magnetic theory of light to its logical conclusion, that all the planets and satellites together with the sun must be electrified bodies, each possessing its electric field.
We have now to determine the effect of such a truth from its dynamical aspect upon the bodies within the field, that is to say, we have to consider the energy of such electric fields, and endeavour to find out the effect of such energy upon other bodies within that field. Maxwell, in his introduction to a paper on "The Dynamical Theory of the Electro-magnet Field," writes on the matter thus: "It appears therefore that certain phenomena in electricity and magnetism lead to the same conclusion as those of optics, namely, that there is an aetherial medium pervading all bodies and modified only in degree by their presence; that the parts of this medium are capable of being set in motion by electric currents and magnets; that this motion is communicated from one part of the medium to another by forces arising from the connection of these parts; that under the action of these forces, there is a certain yielding depending upon the elasticity of these connections; and that therefore energy in two different forms may exist in the medium, the one form being the actual energy of motion of its parts, and the other being the potential energy stored up in the connections in virtue of their elasticity."
The two forms of energy he gives us in his work on Magnetism and Electricity, where, in the quotation already given in Art. 79, he states them to be electro-static and electro-kinetic energy, while in paragraph 792 of the same work he adds: "The intrinsic energy of the medium is half electro-static and half electro-kinetic, that is, half is due to electricity and half is due to magnetism."
We are, however, only dealing at this point with the electro-static energy in the electric field, as we shall deal with the electro-kinetic energy in the following chapter.
We have, therefore, to conceive of an electrified body generating electric or electro-magnetic waves, which speed away from the generating source on every side with the velocity of light. Now we have already seen that the aetherial waves which give rise to heat and light possess a repulsive power, that is, they exert a pressure on the body with which they come into contact.
If, therefore, in the electric field there is this energy manifested as proved by Maxwell, and that energy takes partly the form of a pressure as stated by Maxwell, then we have in the electro-static energy of the electric field, another indication of that centrifugal force for which we are looking, and whose existence was so satisfactorily demonstrated to Herschel by the phenomena of comets' tails.
That there is this pressure in an electric field was conclusively proved by Maxwell, and experimentally demonstrated by Professor Lebedew (Art. 77). Maxwell distinctly states on this point, "that the combined effect of the electro-static and electro-kinetic stresses is a pressure equal to 2 P. in the direction of the propagation of the waves," that is, away from the electrified or charged body.
He continues: "Thus, if in strong sunlight the energy of light which falls on one square foot is 83.4 foot-pounds per second, the mean energy in one cubic foot of sunlight is about .0,000,000,882 of a foot-pound, and the mean pressure on a square foot is .0,000,000,882 of a pound weight. A flat body exposed to sunlight would experience this pressure on its illuminated side only, and would therefore be repelled from the side on which the light falls."
This pressure only gives the result due to the pressure of one cubic foot of sunlight. What must be the pressure, therefore, due to the whole of the sunlight received by the flat body from the sun? The total pressure, whatever it may be, would be equal to 2 P. according to Maxwell, and half of that is due to electricity, and half due to magnetism. Now such a result is entirely in harmony with the conception of the Aether as given in this work. For, if Aether possess an electric basis as suggested by Maxwell, and it is also gravitative as suggested in Art. 45, then it must follow, as pointed out in a previous Art., that throughout the field there is a varying difference in the potential of the field; the potential being regulated by the electric density, that density being equivalent to the aetherial density. Further, as the elasticity of the medium which regulates the pressure is proportional to the density, so the pressure must decrease, as the elasticity decreases—that is, as the electric potential decreases, or the electric density is diminished. Therefore, if the sun be an electrified body, ever generating electro-magnetic waves which speed away from it on every side, then, whenever any of these waves come into contact with a planet or comet, that planet or comet would be repelled from the sun by the pressure of these electro-magnetic waves to which the sun gives rise in its electric or electro-magnetic field.
Thus we again come to the conclusion that the sun is not only the centre of a centripetal force due to Gravitation, and subject to certain laws, whose physical cause is unknown, but it is equally the centre and source of a centrifugal force, in that it is an electrified body, and gives rise to electric waves which produce a pressure on any body upon which they fall, in the sun's electric or aetherial field. It has only to be demonstrated, therefore, that this centrifugal force satisfactorily fulfils all the laws required as laid down in Art. 24, that is, that its course is along the same path as the Centripetal Force of Gravitation, that it is subject to the same law of intensity, which is inversely as the square of the distance; and further (what is the most important at this stage), that the combined effect of the pressure of two bodies is equal to the product of their masses, then we shall have discovered that which we set out to discover, viz. a complementary force to the attractive force of Gravitation.
Unlike the centripetal force, however, the centrifugal force will be purely a physical one, due to a purely physical medium, the Aether, whose properties and motions can be accounted for on a physical, and not on a hypothetical basis.
Further, as the planets are also electrified bodies (Art. 81), they too will possess an electric field, and will generate electric waves, which will also exert a centrifugal force upon all bodies upon which the waves fall. So that, like the sun, the planets are not only the centre of a centripetal force, which ever acts towards their centre; but they are also the centre of a centrifugal force, due to the aetherial electric waves to which they give rise in the Aether.
The application of the same principle may be extended to every satellite that exists in the solar system, and indeed to every particle and atom of matter that exist throughout the universe, for wherever we find the Aether, there we find this centrifugal force, which is due to the electric aetherial waves generated by the atom or particle of matter, or by any combination of atoms, as a meteor, satellite, planet, sun or star.
[Footnote 30: Collected Papers, by Niven.]
[Footnote 31: Magnetism and Electricity, Arts. 791 and 793.]
ART. 83. Electric Radiation.—We learn, therefore, that the sun, together with every planet and satellite in the solar system, is the centre of a centrifugal force, which is due to the radiation of electric waves by an electrified body. We have now to prove that this force fulfils all the laws required, in order for it to become the complementary law to the Centripetal Force of Gravitation. We will first show that this centrifugal force which proceeds from the electrified body is radiated out into space in straight lines with the velocity of light and radiant heat.
As we have already seen, it was due to the genius of Hertz to show the identity between electric radiation and radiant light and heat. In his paper on Electric Radiation he says: "I have succeeded in producing distinct rays of electric force, and in carrying out with them the elementary experiments which are commonly performed with light and radiant heat." We have seen in Arts. 65 and 76 that radiant heat and light are propagated in straight lines, so that, according to Maxwell's electro-magnetic theory, a ray of electric radiation should also be propagated in straight lines.
This Hertz proved, and gave his results in his paper "On the Action of a Rectilinear Oscillation upon a Neighbouring Circuit," in which he fully demonstrated that when electric action takes place between two charged bodies, the electric force is radiated out into space in straight lines in the same way that light and radiant heat are radiated. In his paper on "The Finite Velocity of Electro-magnetic Actions," he showed that the velocity of the electro-magnetic waves was the same as that of light. In the summary of this paper (paragraph 3) he states: "There are many reasons for believing that the transverse waves of light are electro-magnetic waves; a firm foundation for this hypothesis is furnished by showing the actual existence in free space of electro-magnetic transverse waves which are propagated with a velocity akin to light."
Again, in his paper on "Electric Radiation," he not only showed how the radiation was propagated in straight lines, like light, but also proved that while it was reflected by metals, the electric beam was able to pass through doors and stone walls, and adds, "that it was with astonishment that one saw the electric beam appear inside a closed room after its passage through the door."
Thus Hertz has shown that both electric and magnetic effects are propagated through the Aether with finite velocity, and that that velocity is exactly the same as the velocity of light. He further proved that this propagation takes place in straight lines, in the same way that radiant heat and light are propagated. This being so, it is necessary for us to apply these truths to the solar system, with a view to find out what such a result teaches us.
We have seen in a preceding article, that the sun is an electrified body; therefore it, too, must generate these electro-magnetic waves, and radiate them into space on every side with the velocity of light. Let us try to picture the scene. Let S represent the sun, and the circle round it represent the equipotential spheres which exist round the sun. (See Figs. 10 and 11.) As the intensity of the electric force is greater nearer the sun than further away, these equipotential surfaces will be closer nearer the sun than further away.
Then let the straight lines which radiate out from the sun represent the path of an electric ray. It can be easily seen that these electric rays cut the equipotential surfaces at right angles, as they pass from the centre of the sun outwards into space. Now these lines not only represent the path which the electric ray takes in its journey through space, but exactly coincide with the electric lines of force as conceived by Faraday. This great thinker and experimentalist not only conceived lines of magnetic forces existing in the dielectric or medium between two electrified bodies, which in this case is the Aether, but also conceived lines of electric force which started at a conductor, or an electrified body, and radiated out into space.
Thus a line of electric force has a definite direction, and always starts from an electrified body. If it were possible to move a planet along one of these lines of force, its path would be that of a straight line. If on the other hand a planet moved at right angles to one of these lines of force, that is, along the surface of an equipotential sphere, then no work would be done against the electric force, as on such a sphere the electric force would be of the same intensity.
So that from Hertz' experiments it can be demonstrated, that if there be any electric force existent in the Aether, due to the action of the sun upon the Aether, then such a force is directed along the path of a straight line into space with the velocity of light, which, as already pointed out, is the path taken by a ray of radiant heat and light, and coincides with the path taken by the centripetal force.
It has been demonstrated that such electric force is accompanied by a repulsive force, or more correctly a pressure, so that here we have further evidence of the existence of a centrifugal force which finds its generating source in the sun, which is also the centre of the attractive force of Gravitation in the solar system.
The application of Hertz' experiments may be made not only to the sun, but also to every planet and satellite that exists in space with the same result; and, further, may be extended to every particle and atom that exists throughout the universe. For, according to Art. 43, we have learned that Aether is universal, and we have seen that it is gravitative, and have learned from the electro-magnetic theory of light that it has an electro-magnetic basis. Therefore, to be thoroughly consistent, we must not stop in the application of this principle at any point in the whole universe.
Either the whole principle is of universal application, or it ceases to be a universal law. Therefore, if there is this centrifugal force operating along a straight line from the centre of an electrified body, such centrifugal force must be in its application universal, in order to be complete, and in order to satisfactorily form the counterpart of the centripetal force which is also universal, and operates along the straight line joining the centres of gravity of any two bodies.
[Footnote 32: Hertz on Electric Waves.]
ART. 84. Law of Inverse Squares.—We have learned therefore from the preceding Arts., that the solar system may be looked upon as an electric field, with the sun as the electrified body occupying the centre. We have also seen that there is a centrifugal force in all electric fields, which is due partly to electric waves, and partly to the magnetic waves of the Aether.
It will be interesting to find out, what law governs the intensity of this force in any part of the field, or at a given distance from the central body. We have seen (Art. 66) that the law governing the intensity of heat at any distance from the sun, is the law of inverse squares. Further, from Art. 75 we have also learned that light is subject to the same law of inverse squares, as indeed it should be, if it be due to one and the same medium, the Aether.
If, therefore, electricity is also due to certain motions of the aetherial medium originated by the action of an electrified body as the sun, in the same way that light and heat waves are originated, then it ought to follow that the repulsive power of electricity is also subject to the same law of inverse squares. As a matter of fact, that is exactly the state of affairs, so that we find the intensity of the repulsive power in the Aether from any central body, due to the electric waves, or the pressure due to the wave motions of the electric Aether, in relation to that body, is governed and controlled by the same law that governs light and heat.
It may be suggested that such a coincidence is not a very strong argument, as all forces emanating from a central body are subject to the same law of inverse squares. In reply to that, I should like to point out, that even that objection only strengthens the conception of the Aether that we are endeavouring to complete. Our contention is, that all physical forces, whether they be light, heat, electricity, magnetism or Gravitation, are all due to the motions of the aetherial medium; which motions may be generated by a heated or luminous or electrified body, and are radiated from such a body in waves of concentric spherical form, and are all subject to the laws of inverse squares.
So that the fact of the intensity of the centrifugal force due to the repulsive power of electricity falling into line with the law governing light and heat is, to my mind at any rate, only a clearer proof of the one common origin of all the physical forces. The law of inverse squares in relation to electricity may be thus stated. The Centrifugal or Repulsive Force between two charged electrified bodies acts inversely as the square of the distance between them.
This law was proved by Coulomb by means of an instrument known as Coulomb's Torsion Balance, and I must refer the reader to any work on electricity for a full establishment of this law. Suffice to say, that it has been experimentally demonstrated that the law holds good in relation to the phenomena of electricity; and, wherever we get the two kinds of electricity present in any medium or conductor, owing to the polarization of its particles, there we have this law operating in relation to the intensity of the repulsions of the two bodies directly concerned.
We have already learned that the sun is an electrified body, and from that hypothesis we have arrived at the conclusion that the earth and all the other planets are electrified bodies. This being so, it naturally follows that the intensity of the centrifugal force between any two of these bodies, as the sun and the earth for example, or the sun and Jupiter, is subject to the law of inverse squares; and that the repulsion of the sun and the earth for each other is always regulated by their distance, being inversely as the squares of the distance between them.
Thus, if the distance between the sun and any planet is reduced to one-half, which is an exaggerated view, the intensity of the centrifugal force is increased four times; if the distance be doubled the force is reduced to four times its former intensity, and so on.
Whatever the distance may be between the sun and any of the planets, if that distance be increased or decreased, then the intensity of the centrifugal force due to electric waves is increased or decreased in accordance with the law of inverse squares. This agrees with the centripetal law of Gravitation, as the Attraction of Gravitation is also subject to the same law of inverse squares, and, as we have seen (Art. 83), its path coincides with the path of centrifugal force, as it pursues the path represented by the straight lines joining the two bodies.
So that, whenever, and wherever, at any point in space in relation to the central body, the sun, the intensity of the attractive force is increased according to the law of inverse squares by the distance from the central body being diminished, at exactly the same time and in exactly the same manner, the repulsive force due to aetherial electric waves is also increased. If the attractive force is doubled, then the repulsive force is doubled. If the attractive force is halved, the repulsive force is halved. If the attractive force is lessened gradually, then the repulsive force is lessened gradually; and if quickly, by the quicker motion of the planet through space, then the repulsive motion is also increased with a quicker motion.
Further, like the repulsive power of light and heat, the repulsive power of electricity takes exactly the same path as the attractive power of Gravitation.
Thus we learn that the sun is the centre of two forces: first, a centrifugal force due to the pressure of the aetherial medium which is ever directed away from the sun, and which may either be produced by electric or thermal or light waves; and second, it is the centre of a centripetal force known as the Law of Gravity, whatever that may be due to. Further, the centrifugal force is also subject to the same law of intensity as the centripetal force, and moreover takes exactly the same path which the centripetal force takes.
So that we have only to prove that they both agree in another particular, viz. that their power is regulated by the product of their masses, and then we shall have discovered a real physical force, which is the exact complement and counterpart of the centripetal force due to gravity.
ART. 85. Second Law of Electricity. (Product of Masses.)—We have now to prove that the centrifugal force exerted by any electrified body operates upon another electrified body in the same proportion and with exactly the same force which governs the centripetal force. From Art. 21 we learn that the centripetal force which is exerted by one body upon another is equal to the product of their masses. In order, therefore, for any centrifugal force to be the exact counterpart of that force, it too must be subject to the same law of proportion, that is, the repulsive force between any two bodies must be equal to the product of their masses.
We have shown that there is a repulsive force exerted by the Aether from the phenomena of heat, light, and electricity, and that that repulsive force or energy fulfils every condition required by a centrifugal force or motion, with the exception of the part referring to the fact that such a force must be proportionate to the product of their masses. What we were unable to accomplish, however, from the phenomena of heat or light we are now able to accomplish from the phenomena of electricity.
For in the phenomena of electricity we find a law which runs thus: "The force of repulsion" (which is the part of electricity we are now dealing with) "between two electrified bodies is equal to the quantities of electricity with which the body is charged." This law was established and proved by Coulomb by means of a delicate instrument known as the Torsion Balance, with which he also established the law of inverse squares.
It will be seen at a glance that there is a slight difference between stating the law of proportion with reference to the centripetal force, and the centrifugal force or motion. In the former we state the proportion is equal to the product of the masses, while in the latter we say that the proportion is equal to the product of the quantities of electricity.
In the one case we deal with the mass of the body, whether it be atom, molecule, planet or star; in the other case we deal with quantities of electricity. At first sight it may seem that there is little, if any, connection between the two laws, but a careful reflection of the hypotheses laid down with regard to the aetherial medium will show that there is not only a close connection between these two laws of proportion, but also that the law governing the repulsive power of the aetherial electric waves is the direct outcome of the law of proportion governing the centripetal force. Let us restate our case in regard to the aetherial medium.
We have learned that the Aether is gravitative, and that it also has an electro-magnetic basis is proved from Maxwell's electro-magnetic theory of light. Let me ask the reader this question therefore. If the Aether be gravitative, what must be the rule governing the extent and density of the aetherial atmosphere surrounding any planet or sun or other body? If the Law of Gravity teaches us anything at all, it distinctly teaches us that the gravitating power of any body is regulated by the mass of the body, as the law states that the attraction is proportionate to the product of the masses. It states nothing about volume or condition of a body.
The exact size or state of a body has no direct result bearing on gravitation attraction; the underlying principle being that the attractive force is dependent on the mass, and only on the mass of a body. So that if the volume of any body, whether atom, planet, satellite or sun, be doubled, its attractive power remains the same, simply because the mass of the whole body remains the same. Mass, we are told by mathematicians, is equal to the volume multiplied by the density, and whenever we increase the volume of a body we decrease the density, the total mass of the body remaining the same.
If the volume be doubled, then the density of the body would be halved, and vice versa, but through all the changes of volume and density that may arise from the addition of heat or diminution of heat, the total mass of a body always remains the same. Looked at from the atomic standpoint, taking hydrogen as unity, an atom of oxygen would always weigh sixteen times an atom of hydrogen, and this principle applies throughout the whole realm of the atomic world. Further, the same principle or law, that the mass is equal to the volume multiplied by the density, is true of the planetary or even the stellar world. Thus the great regulating principle of the attractive force of gravity is mass, and not volume, or density, or any other condition.
Now as Aether is subject to the attractive force of gravity, the extent of the aetherial field, and the density of the Aether near the surface of any body, must be subject to the same law regarding mass. That is, the aetherial atmosphere of any atom, or molecule, or satellite, or planet, or star is dependent upon the mass of the atom, the molecule, or the planet, or the star as the case may be.
Thus an atom of oxygen would have a larger or denser aetherial atmosphere than an atom of hydrogen, exactly proportionate to their respective masses. A planet whose mass was represented by 1,000,000 tons would have twice the quantity of Aether around it, compared to a planet weighing only 500,000 tons, and so on, the aetherial atmosphere always being proportionate to the mass of the planet, or the satellite, or the sun, or the star. The fact which we learn from these considerations is that the quantity of Aether, which is attracted by any body, is always proportionate to the mass of the body attracting it.
But we have learned from Art. 78 that Aether has an electro-magnetic basis, and that the density of the Aether is co-equal with electric density, so that the quantity of Aether which is attracted and held bound by any body is really equal to the quantity of electricity that such a body is covered with, or is charged with. If the quantity of Aether around any body is doubled because its mass is doubled, then the quantity of electricity is also doubled, but as long as the mass remains unaltered, the quantity of electricity held bound by that mass remains unaltered also. The area of the mass may be doubled, and in that case the density of the electricity would be halved, but as long as the mass remained the same, the quantity of electricity would remain the same also. So that we learn from this reasoning that the mass of a body, and quantities of electricity on that mass, are always proportionate to each other, because of the fact that Aether is gravitative, and also has an electro-magnetic basis.
If we wanted further evidence of the hypothesis that has just been advanced, such evidence is to be found in the hypothesis suggested by Faraday as to the electro-chemical equivalents of all elements. According to this hypothesis every element has its exact electro-chemical equivalent, or definite quantities of electricity are to be found in association with each and every particular atom of each element. Writing on the subject in his Exp. Res., par. 852, he says: "The theory of definite electro-chemical action appears to me to touch upon the absolute quantity of electricity or electrical power belonging to different bodies. Although we know nothing of what an atom is, yet we cannot resist forming some idea of a small particle which represents it to our mind, and though we cannot say what electricity is, so as to be able to say whether it is a particular matter or matters, or mere motion of ordinary matter, yet there is immensity of facts which justify us in believing that the atoms of matter are in some way endowed or associated with electrical powers to which they owe their most striking qualities, and amongst them their chemical affinity." Further, in Art. 857, he states: "I can have no doubt that, assuming hydrogen as 1, and dismissing small fractions for the simplicity of expression, the equivalent number or atomic weight of oxygen is 8, of chlorine 36, of bromine 78.4, and of lead 103.5, etc., notwithstanding that a high authority doubles several of these numbers."
Then, writing upon the definite relationship of these equivalents in compounds, he states (Art. 835): "Electro-chemical equivalents are always consistent, that is, the same number which represents the equivalent of a substance A when it is separating from a substance B will also represent A when separating from a third substance C. Thus 8 is the electro-chemical equivalent of oxygen, whether separating from hydrogen, tin, or lead; and 103.5 is the electro-chemical equivalent of lead, whether separating from oxygen, or chlorine, or iodine."
Here, then, from the pen of one of the greatest thinkers and experimentalists of modern times we have confirmatory evidence that the mass of any body is practically synonymous with the quantity of electricity associated with that body. For if the principle is true in its application to atoms, it is true in its application to molecules; and if it is true in relation to molecules, it is equally true in relation to small bodies composed of molecules. And if it holds good in relation to small bodies, the principle is equally true in its application to larger bodies, as the earth, and therefore is of universal application and proves the statement already made, that the masses of bodies and quantities of electricity in association with that mass are always proportionate to each other.
We are now in a position to compare the proportion of the centripetal and centrifugal forces. The attractive power of the former, between two bodies, is equal to the product of their masses; the repulsive power of the latter is equal to the product of the quantities of electricity bound to them, and that, as we have seen, is regulated by the respective mass of each body. Let us apply this fact to the solar system and see how it works.
Taking the mass of the earth as unity, we find that the mass of the sun is 324,000 greater, so that the attractive power of the two bodies would be represented by the product of the two numbers; but because the sun is that number of times greater, its aetherial and, therefore, its electric field would be so many times greater, with the result that the proportion of the repulsive forces between the two bodies would be exactly the same as the attractive forces between the two bodies, that is, if the mean distance remains the same.
In the same way, it can be shown that the attractive forces between the earth and Jupiter exactly equal the repulsive forces between the two planets at their mean distance, or the attractive forces between any two planets or satellites are exactly counterbalanced by the repulsive power of the centrifugal force at their mean distances.
Thus the centrifugal force of every body is the exact opposite of its centripetal force at their mean distance, because the laws governing the centrifugal force are the exact counterpart of the laws governing the centripetal force. A comparison of the two will prove this. From Arts. 20, 21, and 22 we have seen that the centripetal force is exerted along the straight lines joining the attracting bodies, that the intensity of the attracting body is inversely as the square of the distance, while the total force is proportionate to the product of their masses.
From the phenomena of light, heat, and electricity, we learn that the centrifugal force due to aetherial pressure is exerted along straight lines, that the intensity is inversely as the square of the distance, while the total force between two bodies is equal to the product of the quantities of electricity, which are regulated by the product of their masses.
Thus, if every planet and satellite could be conceived to be motionless in space, and these two forces could be set in operation without producing rotation or translation in space, which is impossible, then every planet and satellite would occupy, by the joint exercise of these two forces, the same position in relation to the sun represented by their mean distances, as long as the solar system existed as a separate system in the realm of aetherial space. We have therefore discovered by strict philosophical reasoning, based on Newton's Rules of Philosophy, a real tangible centrifugal force existing throughout the universe; because it is entirely due to the pressure of an universal Aether, whose operation is ever directed from a central body, which force was indicated by Herschel, and its existence to his mind was demonstrated by the repulsion exhibited in connection with the tails of comets.
We have now to go a step further, and show that the same pressure also includes the magnetic phenomena, as indicated by Clerk Maxwell, and that magnetic phenomena are also due to the aetherial medium, and then we shall have linked together in one common medium the majority of the forms of energy, as light, heat, electricity and magnetism, with which we are familiar.
If it be demonstrated that these two forces, the centrifugal force and the centripetal force, can conjointly account for all the motions of the celestial bodies, then we shall have conclusive evidence that one of the forces is physical and due to the pressure of a physical medium. After that it will be comparatively easy to show that the centripetal force is also due to the same aetherial medium, and then we shall have accomplished that which we set out to accomplish, viz. the establishment of a physical cause for universal Gravitation, which physical cause is alone to be found in the pressures, tensions and motions of an universal Aether.
AETHER AND MAGNETISM
ART. 86. Electro-magnetism.—We have now to look at the relation of magnetism to electricity, or, in other words, to prove the identity that exists between magnetism and electricity. In Art. 78 we have proved the identity between electricity and light, so that if we can now prove the identity between electricity and magnetism, then, wherever we get aetherial light waves, we must also get aetherial electro-magnetic waves.
As the light waves due to the vibrations of the Aether are practically universal in extent, then it must follow, if the identity of the light waves with electro-magnetic waves is established, that the universality of electro-magnetic waves is established also, with the natural result, that, wherever we get these electro-magnetic waves, there we shall have the conditions by which all electro-magnetic phenomena are produced.
Now it can be demonstrated by actual experiment that wherever we get a circular current of electricity, there we have magnetic phenomena manifested. The two are inseparably connected, and it is impossible to obtain the one without the other. For example, suppose we have a wire conveying a current of electricity and make it into a coil as in Figure 15, what is the result? The result is, that the coil of wire has actually been converted into a magnet.
It will attract iron filings that are brought near it, and also magnetize an iron bar placed in the centre of the coils, and convert that into a magnet. Indeed, there is nothing which can be done by an ordinary bar magnet which cannot be done by a coiled wire conveying an electric current.
From this and similar experiments it can be demonstrated that wherever we get a circular current of electricity, there, associated with that current, are all the phenomena incidental to and associated with the ordinary bar magnet. This leads us to the truth discovered by Ampere, that magnetism is nothing more or less than electricity in rotation, or that it is due to a whirl of electricity circulating round the molecule of any body. From certain experiments which he made in relation to the mutual action of two circuits on each other, with currents flowing through them, he came to the conclusion that the magnetism of the molecule of each magnet is due to electric currents circulating round it.
The question arises as to what effect our new theory of the Aether has upon Ampere's theory: does it confirm it, or does it destroy it? We have learned that every atom has its aetherial atmosphere, so to speak, which is bound to the atom by the Law of Gravitation (Art. 45). We have also learned that Aether has an electrical basis, as proved by Maxwell and Hertz, so that we learn that every atom has really an aetherial electric atmosphere in association with it. We have only to conceive of this atmosphere being set in rotation either by the rotation of the atom or molecule itself, or by outside agencies, and we have at once a physical interpretation of Ampere's theory of magnetism in the rotation of electric currents around the atom, such currents being due to the circulating or rotating motion of the Aether which surrounds the atom or molecule.
Thus we learn from experiment, and from Ampere's theory also, that magnetism is directly associated with circulating currents of electricity, and that wherever we get currents of electricity circulating round any atom or body, there we get all the phenomena associated with magnetism. That is to say, we shall have such phenomena as magnetic fields, magnetic lines of force, magnetic induction, and the production of permanent magnets by electricity.
Further, with reference to the identity of electricity and magnetism, Faraday has conclusively proved their relation to each other; and I would strongly advise any reader who desires further light on the subject to carefully read paragraphs 3265-3269 in his Experimental Researches, where he will find experiments which place the identity of electricity and magnetism beyond the possibility of doubt. In paragraph 3265 he writes: "The well-known relation of the electric and magnetic forces may be thus stated. Let two rings in planes at right angles to each other represent them. If a current of electricity be sent round the ring E in the direction marked, then lines of magnetic force will be produced. As these rings represent the lines of electro-dynamic force and of magnetic force respectively, they will serve for a standard of comparison."
"I have elsewhere called the electric current or the line of electro-dynamic force an axis of power having contrary forces exactly equal in amount in contrary directions (517). The line of magnetic force may be described in precisely the same terms, and these two axes of power considered as right lines are perpendicular to each other," etc.
Again in 3267 he adds: "Like electric currents or lines of force, or axes of power when placed side by side attract each other. This is well known and well illustrated when wires carrying such currents are placed parallel to each other. But like magnetic axes of power or lines of force repel each other. The parallel case to that of electric currents is given by placing two magnetic needles side by side with like poles in the same direction."
Then in 3268 he shows that these effects are not merely contrasts, but they are contrasts which coincide when the two axes of power at right angles to each other are considered. Then in 3269 he adds: "The mutual relation of the magnetic lines of force and the electric axis of power has been known since the time of Oersted and Ampere," and further states he is of the opinion that "the magnetic lines have a physical existence the same as the electric lines," and having that opinion, asks whether "the lines have a dynamic condition analogous to the electric axis to which they are so closely and inevitably associated, or whether they consist in a state of tension of the Aether round the electric axis, and may therefore be considered as static in their nature." Thus Faraday proved the intimate and close relationship that existed between the electric current and the circles which represent the magnetic force in association with that current; and, what is more noticeable, he asks whether such magnetic results are due to a state of tension in the Aether around the axis of the electric current, evidently being of the opinion that the Aether played an important part in the phenomena of magnetism, as well as in electricity, as other parts of his writings abundantly show.
If, therefore, there is this close identity between electricity and magnetism, then in view of the fact that all electricity is due to the motions of the universal Aether, it must follow that all magnetism is also due to motions of the same aetherial medium, which is as universal as it is invisible.
What these motions are has already been indicated by previous statements in this article, being comprised of circular or rotatory motions of the aetherial electric medium about any body, whether that body be an atom, planet, or sun or star. Such a conclusion as this is perfectly in harmony with Maxwell's electro-magnetic theory of light, as the conclusion that he arrived at in that theory was, that the light waves were identical in nature and character with electro-magnetic waves produced by an electro-magnetic source.
Up to the present we have only dealt with the electric character of those waves, and have therefore now to deal with the magnetic character of the same. So that throughout the whole realm of space, and indeed wherever there is Aether, there we have the conditions which give rise to magnetic phenomena, such as those already indicated.
It matters not whether it be in the atomic systems whose combinations comprise all material forms of life with which we are familiar, or whether it is in the systems of planets that revolve around their central sun, or whether it be in the constellations that fill the universe, wherever we find the Aether, there we find the conditions in that Aether which will produce all the results ordinarily produced by magnetism, or with which magnetism is associated, and it is to the application of these phenomena to our solar system that we will now turn our attention.
ART. 87. The Earth a Magnet.—If there is any fact in relation to a planet that holds good, it is that the earth, with which planet we are more intimately associated than any other, is a magnet.
This truth was clearly explained by Dr. Gilbert about the year 1600 in his work on "De Magnete." Not only has the earth geographical North and South poles, but it has also magnetic North and South poles, and indeed has all the phenomena incidental to a magnet, such as magnetic dip and magnetic lines of force, as we shall see later on.
We know, however, that the earth is simply one of a system of planets, which revolves with all the others of that system round its central body the sun; and the question arises, whether the earth is the only one out of all the planets that is actually a magnet. Suppose it is affirmed that the earth is the only planet which is a magnet. On what basis would such a statement be made? The only ground for making such a statement that I can see is, that we have never lived on Mars or Jupiter or Saturn, or any of the other planets, and therefore been unable to experiment on them, which reason is totally insufficient and inadequate for such a conclusion.
If philosophy simply dealt with the results attained by such limited reasoning, then the progress of science would be retarded, and would be limited and confined to actual experience obtained on our own planet and in relation only to that planet. But philosophy is not satisfied with such a narrow and limited outlook, but drawing its conclusions from actual experience on our own planet, in accordance with the rules of philosophy, it seeks to apply such experience gained to the explanation of phenomena of other planets which also revolve round the sun.
By such reasoning we learn that all the other planets have North and South geographical poles like our earth, although we have never actually trodden on those planets, or discovered the poles. We also learn that Mars possesses climatic conditions probably similar to our own earth, as there are certain changes on the surface around the poles, which by analogy we assume to be caused by increase and decrease of snow during the Arctic winter and summer of Mars respectively.
The analogy between our earth and the other planets is very full and complete, as the following results show. Our earth has an atmosphere, so have all the rest of the planets. The earth revolves on its axis from West to East, so do all the rest. The earth possesses two geographical poles, so do all the other planets. The earth revolves round the sun in an orbit of elliptic form, so do the other planets. The earth fulfils all the laws of motion as given by Newton, and all the other planets do the same. The earth fulfils all Kepler's laws, and this is also true of all the others. Indeed, the only difference apparently that exists at present between the earth and all the other planets is, that our earth is a magnet, while at present it is not conceded that all the others are magnets.
Now such a conclusion I venture to say is altogether opposed to every rule of philosophy. For if experience be any guide in philosophy, then according to experience and observations made in respect to the only planet that we can actually experiment on, it most conclusively follows, that not only the earth, but every planet, and indeed every satellite that revolves round its primary planet, is a magnet; otherwise the rule of philosophy which permits us to formulate hypotheses based on experience is entirely violated, and ceases at once to be an universal rule.
So that either the earth is not a magnet, or else, being a magnet by our second Rule of Philosophy, all the other planets are magnets also. This conclusion has already been arrived at by Lord Kelvin, who in writing in his Popular Lectures on the subject says: "If it is true that terrestrial magnetism is a necessary consequence of the magnetism and the rotation of the earth, other bodies comparable in these qualities with the earth, and comparable also with the earth in respect to materials and temperature, such as Venus and Mars, must be magnets, comparable in strength with the earth; and they must have poles similar to the earth, North and South poles on the North and South sides of the equator. It seems probable also that the sun, because of its great mass and its rotation in the same direction as the earth's rotation, is a magnet, with polarities on the North and South sides of the equator, similar to terrestrial North and South magnetic poles." Further, such a conclusion is entirely in harmony with the view of the solar system revealed in Art. 81, where we saw that each planet was an electrified body having its own electric field, with its lines of force, being capable of giving rise to all the phenomena associated with electricity. So that if we combine that view of the subject with the view that we are now coming to, we arrive at the conclusion that each planet and satellite, and indeed all bodies that move or revolve in space, are electro-magnets giving rise to magnetic waves in the Aether, which assumption is fully consistent with the electro-magnetic theory of light.
We must now go one step further and apply a similar line of reasoning to the sun, when we shall arrive at exactly the same result that Lord Kelvin arrived at, according to the previous extract. All planets possess an atmosphere, the sun also possesses an atmosphere. All planets revolve on their axes from West to East, so does the sun. All planets possess a North and South pole the same as the sun.
The equatorial diameter of every planet is greater than its polar diameter, and the same truth applies to the sun. It is hotter at the equatorial regions of every planet, and this truth also applies to the sun. Now, if the sun agrees with all the planets in these respects, then we may philosophically conclude that it agrees with them in another respect, viz. that the sun is also a magnet possessing its own magnetic field, which is co-equal and co-extensive with its aetherial electrical field. We have already seen that the sun is an electrified body, possessing its electric field, with its electric lines of force. Therefore the sun is also a magnet, or, to speak more correctly, it is an electro-magnet, and as such gives rise to electro-magnetic waves.
The conclusion to which we have come, that the sun is an electro-magnet, can be arrived at from an altogether different method of reasoning, and as that different method of reasoning will tend to confirm the statement made, I will just indicate it, and then leave it for fuller development in another article.
It is a matter of common knowledge to all students, that the magnetism of the earth varies in several important particulars from time to time. The magnetic poles of the earth do not always occupy the same place in relation to the geographical poles, so that the magnetic force varies as regards intensity or magnitude. The reasons of the variations have never been satisfactorily accounted for, though various hypotheses have been suggested as a solution from time to time.
There is, I believe, only one satisfactory solution to the problem, and that is, that the sun is an electro-magnet, and this conclusion may be arrived at by strictly adhering to Newton's rules of Philosophy. For we have learned that any hypothesis put forward to account for any phenomena, must be simple in character, must agree with experience and observation, and, lastly, must satisfactorily account for the phenomena sought to be explained.
Here then are the variations in time of the magnetic force of the earth, the variations in intensity, and in the inclination of the magnetic axis, together with other variations. What solution shall we offer to such a problem? The only philosophical solution that can be suggested lies in the statement that the sun is an electro-magnet. Such statement is simple in conception, does not violate our experience or observation, as we find a similar revolving body, the earth, which is a magnet; and further, such a statement I premise will satisfactorily account for the whole of the variations and changes in relation to the magnetic forces of the earth. We shall see that this is so when we consider more fully the sun as an electro-magnet. Therefore, apart altogether from any previous analogies, we can philosophically arrive at the conclusion that the sun is an electro-magnet, as well as all the planets.
That being so, it will possess its magnetic field, its magnetic lines of force, and be capable of bringing into operation in the solar system all the phenomena or effects associated with any ordinary magnet that we may experiment with on the earth.
[Footnote 33: Popular Lectures, Vol. II.]
ART. 88. The Sun an Electro-magnet.—If the sun is an electro-magnet, as stated in the previous article, then it is necessary for us to apply the phenomena of magnetism to it in order to ascertain what effect such application will have on the solar system as a whole.
The first thing that we will look at is the magnetic field which is always associated with every magnet. The magnetic field may be defined as that region or space around every magnet in which the magnetic force acts or is in operation. An illustration of a magnetic field may easily be obtained by taking a bar magnet and bringing near to it a magnetized needle, when it will be found that the needle will set itself in various positions relative to the magnet, on account of the lines of force which exist in the field. Thus let A B (Fig. 17) be a bar magnet with its North pole at point A and South pole at point B. If a number of freely suspended needles be hung above it, as shown in the figure, they assume the positions indicated there. It will be seen that at the North and South poles the needles hang vertical, while midway between the two poles there is no dip of the needle, as it is parallel to the bar magnet; while between the place of no dip and the place of vertical dip, which is directly over each pole, the dip gradually changes, becoming more and more vertical as it gets nearer to the pole. If the bar magnet be a strong one, then its magnetic field will be manifested at a great distance; and any magnetized needle brought into the field will be, affected by the same, and will tend to set itself along the lines of force.
As already stated in Art. 80, it was Faraday who originated the term "Lines of Force," and gave to the world some idea of the motions of the aetherial medium, which plays so important a part in electro-magnetic phenomena. A visible manifestation of these lines of force which gather round every magnet may be made by strewing iron filings over a piece of glass, underneath which are several bar magnets, when it will be found that the iron filings will set themselves in well-defined lines or curves, which Faraday termed "Lines of Force."
As the bar magnets are placed in different positions, North pole to North pole, or North to South, and so on, the iron filings will change the figures assumed, indicating in, each case the effect of the lines of force of each magnet upon one another. The iron filings strewed over the magnet are magnetized by induction, with the result that the North pole of one filing attracts the South pole of the next one to it, and this is continued along the whole of one line of force, as revealed by the united iron filings. Faraday believed in the real physical existence of these lines of force, and that belief has been perfected by Clerk Maxwell in two papers which he wrote on "Physical Lines of Force," which will be considered in another article. We will simply deal with them at present as indications of the existence of the magnetic forces in the medium surrounding any magnet.
Let us apply these facts to the solar system and see what the application yields. We have the sun revolving in the Aether medium represented by the circle S in Fig. 19. Then we have the lines of force extending in curved lines E. and W., but in almost straight lines North and South. We will suppose the axis of the sun to be vertical for the sake of simplicity. It may be asked, how far will these lines of force stretch out into space? The reply is that they stretch and extend throughout the whole solar system, and far away into the depths of space, though with ever-decreasing intensity according to the law of inverse squares. Wherever the aetherial light waves are manifested, there the electro-magnetic waves, with all that they imply, are manifested also. We know that the light waves are existent at least as far as Neptune, a distance of 2800 millions of miles, therefore at least to that extent the electro-magnetic waves are manifested; and wherever the electro-magnetic waves to which the sun has given birth are manifested, there we have the existence of the electro-magnetic field, which is co-existent and co-extensive with the electric field of the sun. Further, wherever we get the magnetic field, there we get the lines of force which are as real as air or ocean currents, and are caused, as Maxwell indicated (Art. 44), by the motions of the atomic Aether. Wherever these lines of force are closest together, there the intensity of the magnetic force is at its greatest.
By actual experiment, it can be demonstrated that the lines of force are closest together nearest to the magnet, and therefore applying that fact to the solar magnetic field, the lines of force should be closest together nearest to the surface of the sun, which is exactly what we have already learned. For if Aether be gravitative, then it will be densest nearest to the sun than further away, and the vortex atoms which represent our aetherial atoms will be pressed more closely together near to the surface than further away.
We have learned that Aether has an electro-magnetic basis, and it is that very fact which gives rise to the existence of these lines of force. So that the magnetic phenomena as indicated in the lines of force conceived by Faraday harmonize with the fact that the sun is an electro-magnet; and that Aether, which has an electro-magnetic basis, is also gravitative, with the result that the lines of force are closest together nearest the surface of the sun, where the magnetic force is greatest in its intensity and power.
Now let us apply the principle of the experiment to the solar system by bringing a magnet into a magnetic field, and let us see what the result is. We have learned from the experiment, that if a magnet is moved along any one of the lines of force the dip of the magnet changes, gradually changing from a horizontal to a perpendicular position in accordance with its relation to the two poles of the magnet. From the previous article we have come to the conclusion that not only is the earth a magnet, but that all the other planets are magnets also, so that if any of these are brought into the magnetic field of the sun, then the magnetic axis of the planet, which corresponds to the needle in our experiment, must assume a certain dip in relation to the sun, setting itself along those lines of force which are in the immediate neighbourhood of the planet.
Let us place the earth, for example, at a distance of 90 millions of miles from the sun in the magnetic equator, or that line which exactly divides the magnetic field into two equal halves. According to our experiment, the magnetic axis will now be exactly parallel with the axis of the sun, that is, exactly vertical, pointing North and South, as seen in position 1 in Fig. 19. But suppose that the earth is to the North of the magnetic equator of the field, what happens then? The result will be that the magnetic axis of the earth will dip towards the magnetic North pole of the sun (position 2, Fig. 19), while if the earth be to the South of the magnetic equator, its axis will dip in the opposite direction (position 3), the magnetic axis setting itself in each case along the lines of force which exist in the Aether in that region or space. Thus it can be seen at a glance, that if the earth changes its position at any time in its orbit in relation to the magnetic equator, such a change will effect the total dip of the magnetic axis. In other words, the magnetic poles which indicate the position of the magnetic axis will not occupy the same position in relation to the geographical North and South poles, sometimes appearing to the East and sometimes to the West, and at other times being coincident with the same as it moves to the North or South of the magnetic equator of the sun's electro-magnetic field.
We have to remember, also, that the earth is constantly varying its distance in relation to the sun, being at a distance of ninety and a half millions of miles at its perihelion, or that part of its orbit nearest to the sun; while it is ninety-four and a half millions of miles at its aphelion, or that part of its orbit furthest away from the sun. This implies that as it proceeds from that point in space furthest away from the sun, and approaches a point nearer to the sun, it will pass into places of greater magnetic intensity, with the result that the intensity of the electro-magnetic waves is increased; and the magnetism of the earth is accordingly affected by that fact.
When we come to deal with the earth as a magnet more directly, we shall see that all the variations of terrestrial magnetism may be satisfactorily explained by the fact that the sun is, as we have indicated in this article, an electro-magnet, possessing its magnetic field with its lines of force, and therefore able to give rise to all the phenomena incidental to and associated with any ordinary magnet.
ART. 89. Aether and Faraday's Lines of Force.—We have now to face the question of the physical character of the Lines of Force conceived by Faraday. We have seen in Fig. 18 illustration of these lines of force, which are manifested by the iron filings in the neighbourhood of a magnet, and the question suggests itself to the mind, as to what is the relation of the Aether to those lines of force? Does the Aether play any part in their existence, and if so what?
Faraday was of the opinion that the Aether did play some part in the existence of the lines, and that they were no mere hypothetical lines, but were caused by the actual physical state or condition of the aetherial medium, which existed around every magnet and every electrified body. On this point he says, Art. 3263: "To acknowledge the action in curved lines seems to me to imply at once that the lines have a physical existence. It may be the vibration of the hypothetical Aether, or a state of tension of that Aether equivalent to either a dynamic or static condition."
Par. 3277: "I conceive that when a magnet is in free space, there is such a medium, magnetically speaking, around it. That a vacuum has its own magnetic relations of attractions and repulsions is manifest from former experimental results (2787). What that surrounding magnetic medium deprived of all material substance may be, I cannot tell, perhaps the Aether."
It was, however, left for Clerk Maxwell to develop the idea as to their physical character, and this he did in his paper on "Physical Lines of Force," Phil. Mag., 1861. He had previously written a paper on "Faraday's Lines of Force," delivered to the Cambridge Phil. Society in 1855 and 1856, but his more matured conception of Faraday's Lines of Force was given in the later article.
What Maxwell did was to conceive a physical theory of electricity and magnetism, by which electrified and magnetized bodies could act upon each other by means of the stress or strain of some medium, which existed in the space surrounding these bodies. Now Faraday looked upon electro-static and magnetic induction as always taking place along curved lines. These lines may be conceived as atoms or molecules starting from the poles of a magnet, and acting on all bodies in the electro-magnetic field. These atoms or molecules, joined together in a definite manner, tend to shorten in the direction of their length, that is to say, there is a tension along the lines of force while at the same time they swell out laterally or sideways. Thus there is a tension along the lines of force, and a pressure at right angles to them owing to their bulging out sideways. Maxwell used as an illustration of the tension and pressure, the contraction and thickening of a muscle. As the fibres of the muscle contract, and the arm or leg is drawn up, the muscle swells in its centre outwardly, and so thickens. Thus there would be a tension along the muscle, and a pressure at right angles to it, which would cause any body placed on it to move away from it, owing to the pressure of the contracted muscle.
In the conception of an aetherial atom (Art. 44) drawn purely from observation of the shape of the earth, we came to the conclusion that the aetherial atom was a spherical vortex atom, or, to be more correct, that it was an oblate spheroid with its polar diameter, so to speak, shorter than its equatorial diameter, and further, that the aetherial atom possessed polarity.
Now if we can conceive of these aetherial vortex atoms being joined together, North pole to South pole, and revolving round their axes, we shall then have an exact image of Maxwell's physical conception of Faraday's Lines of Force.
We know that when any liquid body is caused to rotate rapidly about its axis, it will expand laterally and contract longitudinally in the direction of the axis; and it was on this analogy that Maxwell worked out his physical conception of the lines of force. Maxwell's fundamental idea was, that in a magnetic field there is a rotation of the molecule ever going on about the lines of force. For example, let A B be a magnet, and A C B be a line of force composed of spherical vortex atoms joined end to end, that is, each North pole (assuming the vortex atoms to be magnets) being directly associated with the South pole of the one next to it, and vice-versa (Fig. 20).
Thus it can be readily seen that there will be a tension along the line of force, while there will be a pressure at right angles to it owing to the lateral expansion, partly due to the rotation of the vortex atom, and partly due to the attraction of the vortices for each other in the direction of the line of force.
Maxwell in his paper says: "It appears therefore that the stress in the axis of the line of magnetic force is a tension like that of a rope." Further, he adds: "Let us now suppose that the phenomena of magnetism depend upon the existence of the tension in the direction of the lines of force, combined with a hydrostatic pressure, or in other words, a pressure greater in the equatorial than in the axial direction. The next question is, What mechanical explanation can we give of these inequalities of pressure in a fluid or mobile medium? The explanation which most readily occurs to the mind is, that the excess of pressure in the equatorial direction arises from the centrifugal force of the vortices or eddies in the medium, having their axes in the direction parallel to the lines of force." He adds: "A medium of this kind filled with molecular vortices, having their axes parallel, differs from an ordinary medium in having different pressures in different directions."
He then goes on to develop the idea in relation to different intensities of the magnetic field. I must, however, refer the reader to the paper itself for fuller details. In his greatest work, writing on this subject, he says: "I think we have good evidence for the opinion that some phenomenon of rotation is going on in the magnetic field, that this rotation is performed by a great number of very small portions of matter, each rotating on its own axis, being parallel to the direction of the magnetic force, and that the rotations of these different vortices are made to depend on one another by means of some kind of mechanism."
From the foregoing extracts taken from Maxwell's writings, we learn that the constitution of the Aether, as given in Art. 44, exactly coincides with, and satisfactorily fulfils the conditions that he lays down with reference to his physical conception of the lines of force around a magnet or electrified body.
So that the theory of Maxwell is not merely hypothetical, as is suggested by scientists, but exactly describes the conditions and state of the atomic Aether medium which surrounds all magnets. We have, however, seen that the sun is a magnet, and therefore it possesses around it on every side, the same as any other magnet, these aetherial lines of force composed of infinitesimal vortices, or mere whirling points which correspond to an aetherial atom.
These aetherial lines of force stretch out into space on every side of the sun, and in fact form concentric magnetic shells around the sun; which magnetic shells coincide with the equipotential surfaces of the Aether viewed merely from the point of elasticity and density of the medium. We learn by experiment, that these lines are closest together nearest to the magnet, which fact agrees with the statement that Aether is gravitative, and therefore the Aether would be densest nearest the sun. That is, the atoms would be pressed closer together, so that the lines of force of which these atoms are composed ought also to be closer together at the surface of the magnet, which we find by experiment is the case. As the sun is an electro-magnet, therefore, it possesses these magnetic lines of force on all sides, forming a series of magnetic shells. We have now arrived by the aid of Maxwell's theory to a physical conception of the Aether from a magnetic standpoint, which fully agrees with our physical conception of the Aether which was arrived at by purely philosophical reasoning, based on Newton's Rules of Philosophy.
Thus we are able to combine into one whole by our conception that Aether is matter, and therefore atomic and gravitative, not only Faraday's Lines of Force, but also Maxwell's physical conception of the same, apart from the solutions given to the other problems of science by the self-same conception, which solutions will be dealt with in their proper order.
As further evidence of Maxwell's belief in the physical existence of Faraday's Lines of Force, let me again quote from his paper on "Action at a Distance," already referred to in Art. 43. He writes: "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.... These lines must not be regarded as mere mathematical abstractions. They are the directions in which the medium is exerting tension like that of a rope, or rather like that of our own muscles."
[Footnote 34: Exp. Res.]
[Footnote 35: Magnetism and Electricity.]
[Footnote 36: Collected Works, by Niven.]
ART. 90. Terrestrial Magnetism.—We have already seen that the earth is a magnet, and like any other magnet will therefore possess its magnetic field with its magnetic lines of force. The earth's magnetic field is co-existent and co-equal with its electric field (Art. 80), and that is co-existent with the earth's aetherial atmosphere which is held bound to the planet by the force of gravity.
How far the earth's magnetic field reaches, is impossible to say, but we know that it extends at least as far as 260,000 miles, the distance of the moon; as we find that this satellite of the earth is affected very considerably by the electro-magnetic attractive power of the earth. Any body which is placed in the earth's magnetic field is affected by the lines of force which exist in the magnetic field; for wherever the field exists, there the lines of force exist also.
These lines of force, which are associated with the earth, extend therefore into space, and any body such as the moon would become a magnet, if not already one by the process known as magnetic induction, which physical process is well illustrated in the action of a magnet upon iron filings strewed over it as in the illustration (Art. 88).
An experiment which well illustrates the inductive power of the earth's magnetism, may be made by placing a poker in one of these lines of force, whose direction can be found at any part of the earth's surface by means of proper instruments. When the poker is so placed, it will be seen that it has actually become magnetized by the magnetism of the earth, and it is itself able to attract iron filings or small needles. These lines of force of the earth are closer together nearest to the earth's surface than further away in space, and congregate around the North and South magnetic poles, where they are greatest in number in a given area, and there the magnetic intensity is the greatest.
Faraday, writing on the terrestrial lines of force, says: "The lines of force issue from the earth in the northern and southern parts with different but corresponding degrees of inclination, and incline to, and coalesce with each other over the equatorial parts. There seems reason to believe that the lines of magnetic force which proceed from the earth return to it, but in their circuitous course they may extend through space to a distance of many diameters of the earth, to tens of thousands of miles."
From this extract it will be seen that Faraday was of the opinion that the lines of force extended beyond the atmosphere of the earth into the Aether, which statement is confirmed by other parts of his writings; though he was not able to give any physical explanation of how these lines extended beyond the atmosphere on account of the doubtful constitution and character of the Aether, although in another part of his work he definitively refers to the magnetic character of space.