CHAPTER IX_Aether and Gravitation

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 Ampère,

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 Ampère'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 Ampère'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.

[Illustration: Fig: 15.]

Thus we learn from experiment, and from Ampère'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.

[Illustration: Fig: 16.]

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 Ampère," 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_[33] 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.

[Illustration: Fig: 17.]

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."

[Illustration: Fig: 18.]

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.

[Illustration: 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 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:[34] "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-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 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."

[Illustration: 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,[35] 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,"[36] 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."[37]

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:[38] "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 in Art.

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 in Art. 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 points out 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. Let _H_

be the sun, _E_ the earth--

[Illustration: 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. _H_ represents the

sun, and _a_ the place immediately underneath it, which is also

coincident with the magnetic equator. Point _a_ will be a line of no

dip, while at point _b_ there 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 rays

of 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 Chapter IV.

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 to Art. 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 varying

velocity. 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.

[Footnote 37: Art. 2850, _Exp. Res._]

[Footnote 38: 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, being

electro-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 in Art. 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 in Art. 86 on 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, which have

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 that

revolution, 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 the _Phil.

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:[39] "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