Fig: 19.
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 magnetismof 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:[33]“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 uponelectro-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, letA Bbe a magnet, andA C Bbe 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, andvice-versâ(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 magnetismdepend 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.”
Fig: 20.
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,[34]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 inArt. 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 andstate 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,“[35]already referred to inArt. 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 mustnot 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.“
[33]Exp. Res.
[33]Exp. Res.
[34]Magnetism and Electricity.
[34]Magnetism and Electricity.
[35]Collected Works, by Niven.
[35]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 itselectric 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.“[36]
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.
In writing on the magnetic character of space he says:[37]“From such experiments, and also from general observations and knowledge, it seems manifest that the lines of magnetic force can traverse pure space, just as gravitating force does, and as static electric forces do (1616), and therefore space has a magnetic character of its own, and one that we shall probably find hereafter to be of the utmost importance in natural phenomena.“ With the view of the Aether presented in this work, viz. that Aether is matter, though in an infinitely more rarefied and elastic form, we can now see the physical cause of the lines of force with which by his imagination he filled all space.
Again, from the conception of the Aether presented to the reader inArt. 45, we learn that around any body in space there are existing aetherial concentric spheres or shells which are equipotential surfaces, or surfaces of equal pressure, and that these surfaces coincide with the electric equipotential surfaces, as shown inArt. 80.
Not only so, but they coincide with the magnetic shells which the lines of force actually form around a circular and globular magnet, as the earth. For it must not be forgotten that these lines of force exist equally on all sides of the earth, and therefore really form a spherical shell, or to speak more correctly an aetherial electro-magnetic shell, which is an oblate spheroid in shape, partaking of the shape of the earth or other planet which the lines of force surround.
If these shells were divided into two equal halves, the line so dividing them would be called the magnetic equator, and on that line any magnet would set itself in a horizontal position, so that all round the earth on the magnetic equator would correspond to a line of no dip. At the magnetic poles, a magnet would set itself vertically, or at an angle of 90°, and between these two parts, the place of no dip, and that of 90°, the dip gradually changes as illustrated in the figure. Again, in relation to the magnetism of the earth we find that there are certain variations in the magnetic force, which not only influence the dip at any place, but also the intensity at that place. The variations in Magnetic Force are chiefly three--
1st. Diurnal Variations.
2nd. Annual Variations.
3rd. Secular Variations.
Let us look at these three variations from the standpoint of the magnetic lines of force which exist around the earth, and around every planet. In relation to the variations of the magnetic forces upon the surface of the earth, Faraday pointsout that these variations are caused by the action of the sun's rays upon the terrestrial lines of force. He uses the following figure to illustrate his meaning. LetHbe the sun,Ethe earth--
Fig: 21.
He writes as follows: “If the magnetic and astronomical poles of our earth be supposed to be coincident, then North and South poles will also represent the North and South magnetic poles, and the different curves cutting the earth will sufficiently represent a course of magnetic lines as they occur at, or about, the surface of the earth.Hrepresents the sun, andathe place immediately underneath it, which is also coincident with the magnetic equator. Pointawill be a line of no dip, while at pointbthere will be dip. This dip will be increased by the action of the sun's rays, because the atmosphere under the influence of the sun's rays has expanded the air, and has thus acquired a power to affect the lines of magnetic force.“
“All the lines passing through the heated and expanded air will, because of its being a worse magnetic conductor, tend to open out, and the mass of heated air will as a whole assume the condition of diamagnetic polarity (2923). The case may be more simply stated for the facility of recollection by saying, that the effect of the sun is to raise the magnetic circles over the equatorial and neighbouring parts from their normal position, in doing which the North and South dip are simultaneously affected and increased.“
Thus it can readily be seen that every day as the earth turns round on its axis, and presents each side of the globe successively to the raysof the sun, there should be a gradual change in the intensity of the terrestrial magnetism. In Art. 2925, Faraday points out that the maximum of dip would be when the sun was at its zenith or directly overhead. With reference to the Annual Variation, Faraday points out (2882) that if the axis of the earth were perpendicular to the plane of its orbit, the intensity and direction of the magnetic forces might be considered constant, but (2883) as the axis of the earth's rotation is inclined 23° to the plane of the ecliptic, the two hemispheres will become alternately warmer and colder than each other, and then a variation in the magnetic condition may arise. The consideration of this annual variation is further considered by Faraday in the subsequent paragraphs to those already quoted, and I must refer the reader to them for fuller details; I wish simply to indicate the possible explanation of the terrestrial magnetism, in so far as that explanation is in conformity with the aspect of the Aether submitted in ChapterIV.
With regard to secular variations Faraday points out (2880) that the temperature of the air at the equatorial parts of the earth is greater than in latitudes north and south, and as an elevation of temperature diminishes the conducting power of magnetism, so the proportion of force passing through those parts ought to be less, and that passing through the cooler parts, greater, than if the temperature were at the same degree over the whole surface of the globe.
Now with our definite conception of the aetherial lines of force traversing space, and existing on all sides of the earth, these suggestions of Faraday's obtain an increased value in relation to the varying intensity of terrestrial magnetism, and will account for the variations in a satisfactory manner from the aetherial standpoint, if taken in conjunction with the electro-magnetic character of the Aether. Of course, what applies to the earth equally applies to all the other planets, as they also are magnets according toArt. 87, so that they will also possess their magnetic fields, with their own lines of force, and their variations in intensity and magnetic dip.
Hitherto we have only considered the problem of the earth and all the other planets, as magnets, from the stationary standpoint, and the problem faces us as to what effect the movement of the earth and all other planets through the Aether will have upon their magnetic fields, and their lines of force. Now from Clerk Maxwell's mathematical calculations, we learn that the movement of any magnetic body through space will practically have no effect upon the relation of the field, and the lines of force to the moving magnet; that is to say, the magnetic field and the lines of force move with the earth and the planets through space, as they journey round the sun with their varyingvelocity. Maxwell has conclusively proved that the mathematical equations for moving bodies in relation to their magnetic lines of force, and induction, are exactly the same as the equations for stationary bodies, and if this be true, then it follows that the physical conditions for both stationary and moving bodies are the same.
On this point Maxwell writes: “By its motions this (moving) matter carries with it its lines of force, and electricity and magnetism may be regarded as free ends of these lines. Hence when both causes act together there can be no relative motion of true magnetism with reference to surrounding matter,“ etc.
“Under these circumstances electricity and magnetism move with the matter in which they are present as if they were indestructible and adhered firmly to the parts thereof.“ So that from Maxwell's equations and statements we learn that the magnetic lines of force around every planet, and every satellite in space, move with the planets in their orbits round the sun. But as these magnetic lines of force are composed of aetherial atoms, as already indicated, it follows that the Aether which is associated with each planet and held bound to it by the so-called force of gravity moves with the planet also.
This result is entirely consistent with our experience and observation, as we shall see later on. We find that the atmosphere, which is also gravitative, moves with the earth, and therefore from experience we are compelled to arrive at the conclusion that the Aether which is also gravitative moves with each planet, and this result is confirmed by mathematical calculations given by Clerk Maxwell, and is in perfect harmony with the same.
Here then is the key to one of the problems that has been the subject of investigation and research for many years past, and one which is at the present time occupying the attention of some of our most advanced scientists, viz. the relation of the Aether to moving matter.
That problem was solved by Maxwell from an electric and magnetic standpoint, and his result was that the Aether, which we now know to be the source of all electricity and magnetism, moves with the moving matter. What is more, this result has been confirmed by actual experiment made by Michelson and Morley in America, which experiment conclusively proves that Maxwell's result is physically correct, and that the Aether does move through space with its associated planet, and therefore its magnetic field and its lines of force move with it because of the electro-magnetic character of the Aether.
[36]Art. 2850,Exp. Res.
[36]Art. 2850,Exp. Res.
[37]Art. 2757,Exp. Res.
[37]Art. 2757,Exp. Res.
Art. 91.Solar Magnets.--We have now to attack the problem as to the cause of all the satellites and planets, together with the sun, beingelectro-magnets. What is the continuing and ever-acting cause which makes all planetary bodies, including the sun, their centre, to be permanent magnets? According to the Rules of Philosophy there are two causes which would be simple in conception, which are suggested by experiment and observation, and both causes would satisfactorily account for all the planets being magnets.
The first cause suggested to our minds is, that in view of the fact that the sun is an electro-magnet, and therefore possesses a magnetic field with its aetherial line of force, all the planets may become magnets by the process of magnetic induction, which process has already been illustrated by the action of the iron filings placed over the magnet. Such a hypothesis would fulfil all the Rules of Philosophy, as it would be simple in conception, would not violate experience, and would satisfactorily account for the fact sought to be explained.
But such a hypothesis would be based upon the assumption that the sun was an electro-magnet, and then we should have to find out the cause of that fact also. Hence the hypothesis that the planets are magnets, because they are situated in the magnetic field of the sun, is not a satisfactory solution of the whole problem, as it fails to account for the fact that the sun is also an electro-magnet. We must therefore seek for another solution of the problem, which, while fulfilling all the Rules of Philosophy as laid down inArt. 3, will also account for the sun being an electro-magnet, as well as every planet, satellite, meteor, or any other body that exists in space. If we can ascertain such a cause by philosophical reasoning, then we may say we have satisfactorily solved the problem as to the cause of all planetary and stellar bodies being electro-magnets.
If, at the same time, we can solve other outstanding problems by the solution thus offered, then such solution is more likely to be correct than if it simply solved the problem of solar magnetism. The only other solution that can possibly present itself to our minds, as to the cause of all magnetism in any planet, sun, or star, is the explanation which has already been given inArt. 86on electro-magnetism.
In that article we learned that magnetism was really due to the circular motion of an electric current; and that, whenever and wherever we had an electric current moving or revolving with a circular motion, there we should always have those conditions which would give rise to an electro-magnet. As long as the current continued to flow in its circular course, so long would there be those conditions which would give rise to permanent magnetism.
Now in the solar system we find that there are these magnets, whichhave been in existence for millions of years. We also learn from the electro-magnetic theory of light that Aether has an electro-magnetic basis, which gives rise to electro-magnetic waves when disturbed, or set in motion by any heated or luminous body. It can readily be seen, therefore, that we have only to set this electro-magnetic Aether in circular motion around any planet or sun, and we have at once a circular current of electricity flowing round that planet or sun, which would give rise to those conditions by which any body within its influence may be formed into a magnet.
Our hypothesis, therefore, to explain the reason why all the planets and the sun are magnets, is that the electro-magnetic Aether moves round the sun or planet or satellite as the case may be, thus giving rise to currents of electricity around the planet or sun, and so forming those conditions in the Aether by which the permanency of any planetary or stellar magnetism may be maintained and perpetuated.
In other words, to put it plainly and tersely, each aetherial atmosphere revolves round the planet, subject to certain limitations, in the same way that the aerial atmosphere turns round with the earth, as that planet revolves on its axis. At first sight, such an assumption may seem impossible, but a little careful consideration will show not only the possibility of such a cause, but will establish it, as the only reasonable and philosophical explanation for the phenomena we are seeking to explain, viz. the electro-magnetism of all celestial bodies.
There is nothing extravagant in this assumption, as we already have a similar illustration in the case of the atmosphere which goes round with the earth as it revolves on its axis. We have only to extend the same principle a little further, viz. to the aetherial atmosphere, and we at once get the true physical conception of the hypothesis suggested to explain the magnetism of all celestial bodies. We have already learned that Maxwell has proved that the equations for moving magnetic bodies are the same as those for stationary bodies, from which we came to the conclusion that the electric and magnetic field of any planet goes with that planet as it revolves on its axis in its journey round the sun.
I would like to ask the reader to try to conceive of any electric or magnetic field traversing space in association with any planet or sun which is revolving on its axis, while that electric or magnetic field does not revolve either partially or wholly with the revolving body. The field can only be stationary relatively to the planet or sun, as it revolves with the planet or sun on its axis.
There may be, as there doubtless are, conditions governing thatrevolution, as is the case with the atmosphere moving and revolving with the planet, but it is an absolute impossibility for Maxwell's equations relating to moving magnetic bodies to be carried to their logical conclusion, without affirming some such hypothesis as we have affirmed in relation to the cause of all solar magnetism.
Let me at once point out, this solution has already been offered by one whose name has been referred to several times. I refer to Professor Challis. Let us see what he has to say as to the cause of the earth's magnetism. In dealing with this subject, and writing in thePhil. Mag., 1872, par. 42, he states: “With respect to all magnetism which has a cosmical origin, the view I now take is that it is due to gyrations of the Aether, produced by the impulses which it receives from the motions of the constituent atoms of the bodies of the solar system. The gyrations may either be immediately generated by the rotations of the bodies about their axes, or directly result from disturbances of the Aether caused by their motions of translation. This impressed motion will be converted into circulatory or gyratory motion. Such circulatory motion will necessarily partake of the motion of translation of the bodies which generate them, so as to have always the same geometrical relation to these bodies provided their motion be uniform.“
In paragraph 46 he continues: “From what has been already argued (42), the motions impressed on the Aether by the earth in consequence of its rotatory or orbital motions result in circulating motions which would be steady motions, having always the same geometrical relation to the position of the earth's centre.“
Again, Ampère and Faraday were also of the opinion that the magnetism of the earth was due to the circulation of electric currents round it, for in par. 446,Exp. Res., Faraday states: “Assuming with Ampère that the magnetism of the earth is due to electric currents circulating round it, parallel to the equator.“
I think it will be seen from these extracts that the hypothesis suggested for all planetary and stellar magnetic bodies is thus confirmed by Professor Challis, and by Faraday and Ampère. Professor Challis in these passages clearly and definitely points out that there are circulatory motions in the Aether, which motions are produced by the rotation of the earth or other body on its axis, and that these circular motions of the aetherial medium always maintain the same geometrical shape relative to the earth's centre. So that we have only to combine with his hypothesis the electro-magnetic basis of the Aether, and we at once get the circulating currents of electricity constantly flowing round the heavenly bodies, which produce and give rise to the permanent magnetism of those bodies.
If we desired still further confirmation as to the circulating motions of the Aether caused by a rotating body, we find it in the writings of Herschel, who in relation to this matter asks:[38]“What is the law of density of the resisting medium which surrounds the sun? Is it at rest or in motion? If the latter, in what direction does it move? Circularly round the sun, or traversing space? If circularly, in what plane? Supposing the neighbourhood of the sun to be filled with material fluid, it is not conceivable that the circulation of the planets in it for ages should not have impressed upon it some degree of rotation in their own direction, and this may preserve them from the extreme effects of accumulated resistance!“ Words like these from one of the most searching intellects of the last century are well worthy of our consideration, and the suggested effect on the Aether caused by the continued rotation of the earth gives us the key not only to the problem of celestial magnetism, but also to the other outstanding scientific problems.
For example, there is the problem of the relation of moving matter to the Aether around it which still remains unsolved. The physical cause of the rotation of the earth, and all other celestial bodies upon their axes, with unceasing regularity, still remains to be discovered. The physical explanation as to the reason why the earth moves round the sun in its orbit according to Kepler's Laws, has yet to be determined, and, lastly, there is the relation of the magnetic vibration to the electric vibration in connection with the electro-magnetic theory of light still to be solved.
Now, presuming that all these can be solved by the philosophical hypothesis, that the electro-magnetic Aether circulates round each planet and sun and star, that revolves in space, then we are justified in our conclusion that such is the true cause of all electro-magnetism that exists in connection with planetary and stellar bodies. I venture to premise that all these problems can be solved by the simple solution here given, and will prove that this solution adequately accounts for all the other phenomena referred to.
Before proceeding to do this, we will endeavour to prove this hypothesis by an altogether different method of reasoning, in order to confirm the statements made in this article. Let us therefore endeavour to form a complete view of the physical state of the solar system, and for the sake of simplicity we will suppose it to be at rest in space. We shall deal with the effect of its motion upon its own planetary system, when we explain Kepler's Laws.
We have, therefore, the Sun in the centre (see Fig. 14) of the system, with Mercury, Venus, the Earth, Mars, Jupiter, Saturn, Uranus, and Neptune revolving round the sun at their respective distances, which are subject to variations owing to certain causes which can be satisfactorily explained. But circulating round the sun, in the same direction as the rotation of the sun on its axis, we have the electro-magnetic Aether, with its wide-spreading flow and extensive electro-magnetic field. In like manner, we have each planet with its aetherial electro-magnetic field, which also circulates round each planet in the same direction as the planet revolves, that is, from west to east, and in the same direction as the sun's electro-magnetic field revolves.
Thus we have to picture the whole of the solar system in a state of regular and harmonious rotation, while each planet adds to the harmony of the rotation by itself rotating in its own aetherial electro-magnetic field, while all rotate in the same direction, viz. from west to east.
Of course there are several objections that can be raised to such a hypothesis, and those objections will be briefly dealt with in a subsequent article, but I venture to think that this hypothesis is the true philosophical explanation of a problem which has formed one of the greatest outstanding difficulties in regard to the Aether medium for many years, that problem being the relative motion of the Aether and Matter. Lord Kelvin, in an article in thePhil. Mag. for July 1901, entitled “Clouds over the Dynamical Theory of Light,“ refers to this very difficulty, and states there are two clouds over the present undulatory theory of light, one of which has reference to the difficulty of conceiving a body like the earth or any planet rushing through the Aether without subjecting the Aether to enormous laceration, and concludes by saying that “we must still regard this cloud as very dense.“ Here, then, is the key to the solution of the problem.
The earth does not rush through the Aether, but the Aether being gravitative, it is associated with and bound to each planet, and accompanies that planet in its journey though space, rotating with it in the same way that the atmosphere does, as we shall prove later on.
This conception is fully in accord with our hypothesis as to the physical explanation of the cause of the electro-magnetic character of all the heavenly bodies, and indeed is the only physical solution that can adequately account for all the varied phenomena hitherto unexplained in connection with the celestial mechanism.
From the foregoing statements, we are now in a position to consider the term Electro-Kinetic Energy, as used by Clerk Maxwell. What does hemean by Electro-Kinetic Energy? Let us see what he has to say about the term himself.
In par. 636 of hisMagnetism and Electricityhe writes: “According to our hypothesis we assume kinetic energy to exist wherever there is magnetic force, that is, in general, in every part of the field. This energy exists, therefore, in some kind of motion of the matter in every portion of space;“ while again, in par. 569, he states: “The electric current cannot be conceived except as a kinetic phenomenon.“ Even Faraday speaks of the electric current as “something progressive, and not a mere arrangement“ (Exp. Res. 283).
Then again in par. 552 he writes: “It appears, therefore, that a system containing an electric current is a seat of energy of some kind, and, since we can form no conception of an electric current except as a kinetic phenomenon, its energy must be kinetic energy, that is to say, the energy which a moving body has in virtue of its motion.“
Here, therefore, according to Clerk Maxwell, the kinetic energy of an electro-magnetic field is nothing more or less than the energy which a moving body possesses in virtue of its motion. Any other explanation of kinetic energy would be opposed to all the Rules of Philosophy; for experience in its widest form incontrovertibly proves that all kinetic energy is associated, and alone associated, with a moving body; therefore in all electro-magnetic fields there is this kinetic energy ever being manifested. We have, however, learned that the solar system forms a huge electro-magnetic field, traversed by lines of force, as Maxwell and Faraday suggested. Therefore, in the solar system, there must be this kinetic energy due to the motion of a moving body, which is the electro-magnetic Aether.
We have, however, just arrived at the conclusion that in the solar system there is ever going on a circulatory or rotatory movement of the electro-magnetic Aether forming currents around each electro-magnet. On the hypothesis of an atomic and gravitating Aether we have, therefore, a medium or body continually circulating, which medium possesses inertia and momentum, and it is philosophically possible for such a rotating medium to possess kinetic energy. So that our explanation of this term, as used by Clerk Maxwell, is, that this kinetic energy is indeed due to the momentum of the moving Aether. Such a hypothesis is strictly philosophical, and literally fulfils the statements made by Clerk Maxwell himself in the paragraphs already referred to.
A remarkable feature about this hypothesis lies in the fact, that it is the very hypothesis that Von Helmholtz suggested as the explanation of the term. He came to the conclusion that the kinetic energy was due tothe momentum of the moving Aether. But with a frictionless Aether such a hypothesis, although correct, was philosophically untenable. In view of the theory of the Aether presented in this work, however, both Clerk Maxwell's and Von Helmholtz's statements find their literal and perfect fulfilment. So that in an atomic Aether, which is gravitative because atomic, and rotatory because it is gravitative, combined with its electro-magnetic basis as proved by Hertz, we find for the first time a correct philosophical explanation of one of the most puzzling terms used by Maxwell in his greatest work onMagnetism and Electricity. This solution alone ought to stamp the theory of an atomic and gravitating electro-magnetic Aether with that authority that is always associated with the names of two such great thinkers and experimentalists as those just mentioned.
The fact that the Aether is held bound to a planet has already been suggested by Sir G. Stokes to account for the aberration of light already referred to. In thePhil. Mag., July 1845, he writes: “I shall suppose that the earth and the planets carry a portion of Aether along with them, so that the Aether close to the surface is at rest relatively to the earth, while its velocity alters as we recede from its surface, till at no great distance it is at rest in space.“ Sir G. Stokes does not, however, say how the Aether is held bound to the earth, and apart from an Aether which is gravitative, no satisfactory explanation can be given. Further, it is noticeable, that he suggests that the other planets also carry part of the Aether associated with them along with each planet as it pursues its journey. It would be distinctly unphilosophical to assume that the earth was the only planet that carried its aetherial field with it. So that by following Sir G. Stokes' suggestion, we practically arrive at the same conclusion in relation to the motions of the Aether that we have already arrived at from magnetic phenomena.
With this view of the case we are now in a position to answer a question asked by Professor Schuster at the British Association in 1892. He asked, “Is not every large rotating mass a magnet?“ and added, “If it is, the sun must be a powerful magnet. The comets' tails, which eclipse observations show stretching out from the sun in all directions, probably consist of electric discharges.“ Now, in relation to this question, the answer is that every rotating body in the Aether is undoubtedly an electro-magnet. Thus, not only is the sun an electro-magnet, but every planet and satellite, and every meteor that rotates in the electro-magnetic Aether, is converted into a magnet, partly by that rotation, and partly by the currents induced in the Aether by that rotation. We shall also find when we come to deal withthe phenomena of comets' tails, that Professor Schuster is also right as to their cause, and that they are due to electro-magnetic repulsions originated in the Aether by the sun, which is an electro-magnet.