Art. 1. Gravitation.--In the realm of Science, there exists a Force or Law that pervades and influences all Nature, and from the power of which, nothing, not even an atom, is free.

It holds together the component parts of each and every individual world, and in the world's revolving prevents both its inhabitants and its vegetation from being whirled off its surface into space. It exists in each and every central sun, and circles round each sun its associated system of planets. It rolls each satellite around its primary planet, and regulates the comet's mysterious flight into the depths of space, while the pendulation of even the remotest star is accomplished by this same force. Our own rocking world obeys the same mysterious power, that seems to grasp the entire material creation as with the grasp of the Infinite.

It exists in, and influences every atom, whose combinations compose and constitute the entire material creation, or each and every orb that bespangle the blue infinity.

As is readily seen, it weaves as it were around each and all, a mysterious network or chain, that binds star to star, and world to world, blending all into one entire, vast and complete unity. It decides all their orbits and distances, regulates and controls all their motions, from the most simple even to the more complex and intricate, ultimately producing that wondrous and beauteous order, unity and harmony that everywhere pervade and blend all the universe into one grand and harmonious whole.

That Law I need hardly say is the Law of Gravitation.Art. 2. Cause of Gravitation.--Now the question arises, and indeed has arisen a thousand times since the discovery of this law by Sir Isaac Newton over two hundred years ago, as to what is the physical cause, the true explanation of this universal attraction. MacLaurin in his work on the philosophical discoveries of Sir Isaac Newton says: “In all cases when bodies seem to act upon each other at a distance, and tend towards one another without any apparent cause impelling them, this force has been commonly called Attraction, and this term is frequently used by Sir Isaac Newton. But he gives repeated caution that he pretends not by the use of this term to define the nature of the power, or the manner in which it acts. Nor does he ever affirm or insinuate that a body can act upon another body at a distance, but by the intervention of other bodies.”

The results of modern discovery show that action at a distance, without the intervention of any medium, as for example the sun attracting the earth, is not the universal condition which governs all so-called forces.

It is now recognized that light and heat are both forms of energy, and therefore forces, using the term in the same sense that it is applied to Gravitation.

Both light and heat are transmitted through space with finite velocity through the intervention of a medium, the universal Aether. It is therefore only reasonable to suppose, that if one or more particular kinds of energy, or forces, require a medium for their transmission, why not another force, as for example Gravitation?

Gravitation is an universal force which operates throughout the length and breadth of the entire universe, and if there be a medium which is to Gravitation, what the Aether is to light and heat, the question at once confronts us, as to what are the characteristics, properties, and qualities of that universal medium, which is to form the physical basis of this universal attraction?

Newton himself suggested that Gravitation was due to an aetherial subtle medium, which filled all space.

In his well-known letter to Bentley, Newton writes as follows: “That Gravity should be innate, inherent, and essential to matter, so that one body can act upon another body at a distance through a vacuum, without the mediation of anything else, by and through which their action and force may be conveyed from one to another, is to me so great an absurdity, that I believe no man who has any philosophical nature or competent faculty of thinking can ever fall into it.”

We also know from his Queries in his book on Optics, that he sought for the explanation of Gravitation in the properties of a subtle, aetherial medium diffused over the universe.

MacLaurin on this point says: “It appears from his letters to Boyle, that this was his opinion early, and if he did not publish his opinion sooner, it proceeded from hence only, that he found he was not able from experiment and observation to give a satisfactory account of this medium, and the manner of its operations in producing the chief phenomena of Nature.”

Therefore, if we accept Newton's suggestion, and endeavour to trace the physical cause of Gravitation in the qualities, properties, and motions of this subtle aetherial medium to which he refers, we shall be simply working on the lines laid down by Sir Isaac Newton himself.

I wish therefore to premise, that the future pages of this work will deal with the hypothesis of this aetherial medium, by which will be accounted for, and that on a satisfactory and physical basis, the universal Law of Gravitation.Art. 3. Rules of Philosophy.--In order that we may rightly understand the making of any hypothesis, I purpose giving some rules laid down by such philosophers as Newton and Herschel, so that we may be guided by right principles in the development of this new hypothesis as to the cause of Gravitation.

The rules that govern the making of any hypotheses, so far as I can discern, may be summed up under the three following heads--

(1) Simplicity of conception.

(2) Agreement with experience, observation, and experiment.

(3) Satisfactorily accounting for, and explaining all phenomena sought to be explained.Art. 4. 1st Rule. Simplicity of Conception.--From this rule we learn that the hypothesis must be simple in conception, and simple in its fundamental principles, and further, that the same characteristic of simplicity must mark each step of its development.

This rule of simplicity is distinctly laid down by Sir Isaac Newton in his Principia, Book 3, under the heading “Regulae Philosophandi.”

In that work he writes: “Natura simplex est, et rerum causis superfluis non luxuriat.”--“Nature is simple, and does not abound in superfluous causes of things.”

He further states that: “Not more of the natural causes of things ought to be admitted, than those which are true and suffice to explain phenomena. In the nature of Philosophy nothing is done in vain, and by means of many things, it is done in vain when it can be done by fewer. For Nature is simple, and does not abound in superfluous causes.”

While again in Rule 3, he adds: “Natura simplex est et sibi semper consona.”--“Nature is simple, and always agrees with itself.”

Whewell also considers simplicity as a fundamental principle of all true hypotheses. On this point he writes: “All the hypotheses should tend to simplicity and harmony. The new suppositions resolve themselves into the old ones, or at least only require some easy modification of the hypothesis first assumed. In false theories the contrary is the case.”

Thus, it is the very essence of philosophy to build upon a foundation of simplicity, combined with the results of experience, observation, and experiment. For example, if we desired to form a hypothesis as to the cause of day and night, two hypotheses might be assigned as to the cause.

First, that the earth revolves on its axis once a day, and so presents each part successively to the light and heat of the sun; and second, that the sun revolves round the earth once every 24 hours. But such an assumption as the latter would involve the revolution of the sun through an immense orbit at an enormous velocity, in order for the journey to be accomplished in the time. So that it is much simpler to conceive of the earth revolving on its axis once every 24 hours, than it is for the sun to perform this journey in the same period. Hence the rule of simplicity is in favour of day and night being caused by the revolving of the earth on its axis. The same rule might be illustrated in many ways; but, however illustrated, the principle, according to Newton, always holds good that all effects are produced by the simplest causes, and if there are apparently two causes to the same phenomenon, then the simpler cause is the true and correct one. So that in the making and development of any hypotheses of the physical cause of Gravitation, this rule of simplicity must always be recognized; and, in conjunction with the other rules, we must seek to make our hypotheses, so as to be able to account and explain all phenomena sought to be explained.Art. 5. 2nd Rule. Experience.--Newton fully recognized the necessity of experience in Philosophy. He saw the absolute necessity of appealing to experience, observation, and experiment, both as a basis for philosophical reasoning, and further, for the data which were necessary to verify particular applications of the hypotheses suggested.

In his Rules of Philosophy, referring to experience as a guide, he says: “Hoc est fundamentum philosophiae.”--“This is the basis of philosophy.”

Herschel, writing on the same subject in his Natural Philosophy, writes thus with regard to experience: “We have pointed out that the great, and indeed the only ultimate source of our knowledge of nature, and its laws, is experience. By which I mean, not the experience of one man only, or of one generation, but the accumulated experience of all mankind in all ages registered in books or recorded in tradition. But experience may be acquired in two ways, either first by noticing facts as they occur without any attempt to influence the frequency of their occurrence, or to vary the circumstances under which they occur. This is observation. Second, by putting in action causes and agents over which we have no control, and purposely varying their combination, and then noticing what effects take place. This is experiment. To these two sources we must look as the fountains of all natural science.”

Herschel further writes: “Experience once recognized as the fountain of all our knowledge of nature, it follows, that in our study of nature and its laws, we ought at once to make up our minds to dismiss, as idle prejudices, or at least suspend as premature, all preconceived notion of what might, or ought to be the order of nature in any proposed case, and content ourselves as a plain matter of fact with what is. To experience we refer as the only ground for all physical enquiry. But before experience itself can be used to advantage, there is one preliminary step to make which depends wholly upon ourselves.”

“It is the absolute dismissal and clearing the mind of all prejudices from whatever source arising, and the determination to stand or fall by the result of direct appeal to facts in the first instance, and to strict logical deduction from them afterwards.”

From extracts like these, from such men as Newton and Herschel, it can at once be seen that experience, and experience alone, should be the chief fountain from whence we draw all our data to form the bases of any hypothesis or theory. If the hypothesis formed is contradicted by the result of any present or future observation or experiment, then such hypothesis will either become untenable, or must be so modified as to take in the new fact furnished by that observation and experiment.

It is a sine qu non of all true philosophy, that philosophy should always agree with experience. To the extent that our Philosophy of Nature fails to agree with our experience, or with the results of observation and experiment, then to that extent it ceases to be philosophy. It may be a hypothesis or even a theory, but certainly it is not true Philosophy.

Now, in the elaboration and development of the theory as to the physical cause of Gravitation, I can premise that nothing will be postulated or supposed, unless such supposition can be directly verified by our own observation and experiments.

Any theory or hypotheses that are contradicted by our own experience in its widest form, will find no place in the development of this work. Further, any present accepted theory in relation to any natural phenomena, which is controverted by experiment, or observation, will be rejected as untenable in the scheme of Natural Philosophy to be submitted to the reader.

Whatever else the theory suggested may, or may not be, one thing it certainly shall be, and that is, that it shall be strictly based upon the Philosophical Rules as given by some of the greatest philosophers the world has ever seen. I do not premise that the hypotheses advanced will be strictly correct in every detail.

That would be to assume that my experience of all natural phenomena was perfect. To the extent that our experience is limited, to that extent our hypotheses will be limited and faulty. It would need an Infinite mind to form a perfect theory of the philosophy of the universe, because only an Infinite mind possesses infinite experience. A finite mind can, however, form true philosophical conceptions of natural phenomena, if that mind will only follow the guidance of his own experience, and be willing to accept the teaching that always arises from the results of that experience. In order to do this, however, it must be observed, as Herschel points out, that all old prejudices must be put away, and the question or problem to be considered must be viewed with an open mind. Let me illustrate what I mean. Suppose, for example, that for two hundred years, chalk had always been thought to be a mineral, and then, owing to the development of the microscope, and to the increased magnifying powers of the lenses, it was conclusively demonstrated that chalk is made up of the shells and remains of certain organisms that lived in the sea ages ago. Would it be philosophical to throw over the results of the microscopical research, and, simply because for two hundred years chalk had been thought to be a mineral, to argue, and still retain the idea that chalk was a mineral?

Such a result would be entirely opposed to all the teaching and principles of philosophy. In a similar way, suppose in the development of the physical cause of Gravitation, a certain conception of the universal Aether has to be put forth in order to account for Gravitation, and that that conception is opposed to some of the theories which have been held relative to the Aether medium for the past two hundred years; but that the conception so advanced is supported by the experiments and observation of some of the ablest scientists of the present century, would it be philosophical to reject the newer conception which harmonized with all experiment and observation, and still retain the old conception of the aetherial medium; or, to accept the newer conception of that medium, and to reject some of the ideas included in the old conception? From a purely philosophic standpoint, there can only be one reply, which would be in favour of the newer conception, by which our philosophy would be brought into harmony with our experience.

This I premise will be done in this work, and the result will be, that for the first time, our philosophy of the aetherial medium will agree with our experience; and, as the natural result, several outstanding problems will be explained on a physical basis, which at the present time cannot be satisfactorily explained except from the mathematical standpoint.Art. 6. 3rd Rule. Satisfactory explanation of the Phenomena sought to be Explained.--The third rule which governs the making of any hypothesis is, that the hypothesis formed in accordance with the first and second rules shall satisfactorily account for all the phenomena sought to be explained.

Newton writes on this point as follows: “No more causes of natural things are to be admitted, than such as are true, and sufficient to explain the phenomena.” While again in his fourth rule he states: “In experimental philosophy, propositions collected by induction from phenomena are to be regarded as accurately true, or very nearly true, notwithstanding any contrary hypothesis, till other phenomena occur by which they are made more accurate, or are rendered subject to exceptions.” Principia, Book 3. Herschel in his Natural Philosophy points out, that one of the chief requirements of any assumed hypothesis is, that it shall be sufficient to account for the phenomena to be explained, and that it shall be suggested by analogy.

Now the object of this work is to give a physical explanation of the cause and working of Gravitation, and to show how, by the properties, qualities and motions of the universal Aether, Universal Gravitation may be accounted for on a physical basis. So that every phenomenon, associated with, or included in the Law of Gravitation, should receive a satisfactory physical explanation by the proposed theory.

Thus the physical cause of the centripetal and centrifugal forces should receive for the first time a physical explanation.

Newton's Laws of Motion, in so far as they conform to his own Rules of Philosophy, should also receive a physical explanation.

Kepler's Laws, which govern the motion of planets in their orbits, should also receive a similar physical explanation. Indeed, all phenomena which the Law of Gravitation explains from a mathematical standpoint, ought to receive a physical explanation by the proposed new conception of the Aether medium.

In addition to the outstanding physical cause of Gravitation, there are other physical problems that yet remain to be solved; as, for example, there is the question as to what is the relative motion of Aether to moving matter. Does the Aether move with matter through space as suggested by Michelson's and Morley's experiment of America, or does it flow freely through all matter, as it is usually thought to do? I premise I will give a satisfactory solution of this problem in due course.

Again, in relation to the Phenomena of Light, there is still outstanding the problem of the physical explanation as to the transverse vibration of light. This problem will also be dealt with from the standpoint of our new conception of the Aether. Whether it will be as satisfactorily solved, as the physical cause of Gravitation, remains to be seen.

Further, there is also the important question yet unsolved, as to what Matter is. Lord Kelvin and Dr. Larmor have recently given to the world certain conceptions as to the origin of Matter, and I shall endeavour to show that such conceptions receive confirmation and support by the proposed new conception of the Aether.

Another problem that will be attacked and solved, will be the cause of the Permanent Magnetism of the earth, with an answer to some of the questions propounded by Professor Schuster at the British Association of 1892 relative to the magnetism of solar bodies.

There is certainly some physical explanation as to the cause of the earth being a magnet, yet up to the present no satisfactory physical theory has been given. I premise that the new conception of the Aether, to be submitted in the after pages, will satisfactorily account, and that on a philosophical basis, for this phenomenon.

Lastly, one of the most interesting discoveries of the present day will receive an added confirmation and explanation in the conception of the Aether medium to be advanced. I refer to the system of Wireless Telegraphy that has been so successfully developed by Signor Marconi, and I premise that new light will be thrown on that discovery by the suggested theory of the Aether.

Now, if all these problems can be partially or wholly solved by the same theory that is advanced to explain the physical cause of Gravitation, it needs no further comment to show that that theory is considerably strengthened and more firmly established.

For it is a rule in Philosophy, that the more problems any suggested theory can solve, the greater are the claims of that theory for acceptance by scientists generally. For, if two rival theories can solve three and ten physical problems respectively, then, in giving a decision as to which is the better theory, the balance of opinion would be overwhelming in favour of that theory which could solve the ten problems. So that, if in addition to the satisfactory explanation of the physical cause of Gravitation, some, if not all of the other problems can be solved, as I premise they can, by the same conception of the Universal Aether, then it follows our third rule of Philosophy will be more than fulfilled, and the theory so advanced will be placed upon such a strong foundation, that it can only be overthrown by proving that it contradicts the results of some undiscovered phenomena.Art. 7. Application of Rules to Gravitation.--Let us therefore apply Newton's own Rules of Philosophy to the Law of Gravitation, and endeavour to find out if the law, as at present understood, fully satisfies his own Rules of Philosophy. No one can reasonably object to subjecting the Law of Gravitation to the test of those principles which he lays down as the fundamental Rules of Philosophy.

If it comes through the ordeal with complete success, that is, if it is essentially simple in its conception and development, and if all its details are fully in accord with experience, as revealed by observation and experiment, then there will be no need to alter any of its hypotheses or axioms. If, on the other hand, it violates any of the rules as laid down by Newton, then, to that extent, an alteration will be necessary, in order that the Law of Gravitation may be brought into conformity with his own rules, and our Philosophy made to agree with our experience and observation.Art. 8. Analysis of Law of Gravitation.--In order to accomplish this, let us ask ourselves, “What are the component parts of this Law of Gravitation?” The Law is not a simple law, but a compound one. It is compounded primarily of three parts.

1st. A Primitive Impulse.

2nd. A Centripetal Force.

3rd. A Centrifugal Force.

To these must be added the three Laws of Motion; although they are not directly part of the Law of Gravitation, yet they are essential to its effectiveness and completion. Without any one of these, the Law of Gravitation would fail to account for all the phenomena that it does account for.

If there were no Primitive Impulse, then the planets and meteors, sun and stars would for ever remain at rest, and the Laws of Motion would remain inoperative. If there were no Centripetal Force, then the Centrifugal Force would hurl the planets and comets, asteroids or minor planets away into the depths of space, never to return to their central sun.

If there were no Centrifugal Force, then the Centripetal Force would draw all bodies, i. e. all planets, etc., to their central sun, and, instead of the planets continually revolving round the sun, there would be but one immense solitary mass in the centre of the solar system.

If there were no Laws of Motion, with their necessary corollary the Parallelogram of Forces, the Primitive Impulse would cease to act, and the Law of Gravitation would again fail in its attempt to account for those phenomena it does account for.

Thus, as it may easily be seen, Gravitation is a compound Law, depending upon at least four hypotheses, and therefore is not essentially a simple Force, or Law.

If, therefore, in giving a physical explanation of the cause of Gravitation, we can reduce all these four elements of the Law into one single physical cause, i. e. the Universal Aether, and show how they may all be explained and accounted for by the properties, qualities and motions of that physical medium, then such a result will be strictly in harmony with the first Rule of Philosophy, as laid down by Newton and others.

We will, therefore, proceed to consider some of these parts of the Law of Gravitation in detail.Art. 9. Primitive Impulse.--This may be explained as follows. At the creating and launching of each world, Newton supposed that there was given to each world an impulse or tendency to fly off from the controlling centre into space. On this matter MacLaurin writes as follows: “If we had engines of sufficient force, bodies might be projected from them, so as not only to be carried a vast distance away without falling to the earth, but so as to move round the whole earth without touching it; and, after returning to the first place, commence a new revolution with the same force they first received from the engine; and after the second revolution, a third, and thus revolve as a moon or satellite round the earth for ever. If this can be effected near the earth's surface, it may be done higher in the air, or even as high as the moon. By increasing the force or power, a body proportionately larger may be thus projected, and by a power sufficiently great, a heavy body, not inferior to the moon, might be put in motion, which might revolve for ever round the earth. Thus Sir Isaac Newton saw that the curvilineal motion of the moon in her orbit, and of a projectile at the surface of the earth, were phenomena of the same kind, and might be explained from the same principle extended from the earth so as to reach the moon, and that the moon was only a greater projectile that received its motion in the beginning of things from the Almighty Author of the Universe.”

Now what I desire to know is, “What is the nature, the mode of operation, and, above all, the physical cause of this Primitive Impulse?” Is it in its nature and mode of operation a simple Force, or Cause? Does it fulfil the condition of Newton's First Rule of Philosophy? Permit me to suggest several lines of thought which may be made the basis of its analysis.

Astronomers tell us that there are in existence millions of stars, and suns, flooding immensity and space with their light and heat.

Now the question I wish to ask regarding Primitive Impulse in relation to all these stars is this: “Was the Primitive Impulse imparted to each sun, and star, and planet, separately and distinctly?” If so, then there must have been just as many Primitive Impulses as there are stars and suns and planets, and there would be according to a certain astronomer's estimate at least 800,000,000 Primitive Impulses, which assumption is altogether opposed to, and violates the First Rule of Philosophy.

If, on the other hand, it is affirmed that they all received their motion at one and the same time, then I ask: “What was the physical cause and method adopted to communicate the impulse to each one at the same time?” If the reply is given, that it was by Universal Gravitation, I have two objections to make to such a reply: first, that Gravitation is altogether inoperative without the Primitive Impulse, otherwise why was it conceived? and secondly, what is the physical cause of Gravitation?

Again, scientists inform us that there is every reason for believing, that stars and suns are still being formed in the universe, and that there are certain distinctive phenomena which go to prove that statement. Now, if that be true, and I believe it to be true, I wish to ask if the Primitive Impulse as suggested by Newton, is applicable to the stars and suns already in process of formation in the various nebulae? and, if so, at what point in the star's history or development is that Impulse applied?

Personally, I cannot conceive of the Great Creator of all things being so lacking in inventive genius, if I may reverently use that term, as to necessitate a separate Impulse being given to every separate star, or sun, as each one is created or formed during the progress and development of the universe of worlds.

I would much rather believe that which I hold to be the correct explanation, viz. that He has given to a certain fundamental and primordial medium, certain qualities and properties, by, and through which are originated and perpetuated, all the motions of the heavenly bodies already existent in the universe, or that are ever likely to be existent throughout all time.

The question of separate Primitive Impulses for separate bodies becomes more and more incongruous and inadmissible, as we consider it in its application to such small bodies as meteors and planetoids. Is it not contrary to our fundamental principles of Philosophy, that a separate Impulse should be necessary for all small bodies that exist in their myriads throughout the solar system, not to speak of the universe of which that system forms a part? Such a conception as Primitive Impulse, to each separate world, is altogether opposed to one's idea of that simplicity and beauty which govern the universe at large, and violates the first rule of our philosophical reasoning, and for this reason must be rejected from the System of Philosophy to be propounded in this work.Art. 10. Centripetal Force.--Let us now look at the Centripetal Force, and ask ourselves what is meant by such a force, and what is its mode of action and working. Centripetal Force, strictly, may be defined as that force which is always exerted towards the centre of the attracting body.

Taking the earth as an example, Newton points out, that though the gravity of bodies arises from their gravitation towards several parts of the earth; yet, because this power acts always towards the centre of gravity of the earth, it is therefore called the Centripetal Force.

This force, then, is that part of the Law of Gravitation which corresponds to the Attraction of Gravitation, and is always exerted in that straight line from the body attracted, to the centre of the attracting body, which joins the centres of gravity of the two bodies concerned.

The combination and effect of the various forces included in the Law of Gravitation are illustrated by the familiar illustration of the ball whirled round the hand by a piece of string, or the bucket filled with water, whirled round in the same way. Let us take the former. A piece of string with a ball attached to one of the ends is held firmly by the hand. An impulse or motion is imparted to the ball by the hand, that motion being continued by the movement from the hand. The first impulse given to the ball by the hand represents the Primitive Impulse. The tension on the string which holds the ball to its controlling centre represents the Centripetal Force, while the opposite force on the string, which takes up the Primitive Impulse and continues it, is represented by the Centrifugal Force.

The conception of the Centripetal Force is therefore simple, and entirely in accordance with our experience as gathered from observation and experiments. Both in the spheres of electricity, and magnetism, we find a similar force acting, which tends towards the centre of the attracting body, and therefore the Centripetal Force satisfies the first two Rules of our Philosophy.

Further, it adequately accounts for certain distinctive phenomena which occur through the Law of Gravitation, as, for example, the falling of bodies to the earth, and therefore is entirely in harmony with all the requirements of those principles enunciated by Newton for the successful explanation of any phenomena. I need hardly point out, therefore, this being so, any physical cause suggested as the explanation of Gravitation must deal with the Centripetal Force, and be able to give a physical explanation of the mode and manner in which the Centripetal Force operates.

The Attraction of Gravitation or the Centripetal Force, however, being, as its name implies, simply a drawing or pulling power to a centre, that is, a force that is ever and ever only drawing matter to matter, or body to body, it could not of, and by itself, accomplish those necessary stellar and planetary motions by which are produced that universal order, unity and harmony which characterize the universe. It is essentially in its operations and influences, a one-sided force, ever tending and influencing towards self, and therefore by itself would only be a detriment and an evil; and, unless it were accompanied by some companion or complementary and counter force, with which it acts in union and concert, and which exactly counteracts its pulling power and influence, it would soon draw star to star, and world to world, crashing and heaping them together in ruinous and dire confusion. So that, instead of the infinitude of worlds which now exist, which flash and sparkle in the heavens, and in their intricate, elaborate, and mazy motions move through the vast infinity like stately armies on the march, there would only be one agglomeration of matter, a silent and solitary mass existing in the vast abyss of space.

Therefore, as soon as Sir Isaac Newton had discovered and demonstrated the existence of the power of Attraction, as represented by the Centripetal Force, and its association with the universe at large, there was seen at once the necessity of another Force, of an opposite character, which would form the companion and complementary force to Attraction; a repulsive, repellent force, one tending or repelling from a centre, so as to counterbalance the influence of the Centripetal Force which ever tends towards the centre.

To fill up the blank, there was conceived to exist what is called a Centrifugal Force, that is, literally, a Force acting, and ever acting from a centre, and with that Force we will now deal.Art. 11. Centrifugal Force.--In applying our Rules of Philosophy to this Force, if by Centrifugal Force is simply meant that Force which is the exact opposite of the Centripetal Force, that is, a Force which acts from a centre, instead of to a centre, then such a Force is strictly in harmony with, and satisfies all the conditions of the two first Rules of Philosophy.

Not only is such a conception simple, but it is also in accordance with experience and observation. Professor Hicks in his address to the British Association in 1895 said: “What is called Centrifugal Force is an apparent bodily Force directed outwards from the centre of curvature of the body's path, and having an intensity equal to the distance from the centre multiplied by the square of the absolute angular velocity.”

In the sphere of magnetism and electricity, the operation of two equal and opposite forces prevails. The attractive force of electricity, which is exerted to the centre, is always accompanied by the generation and development of a repulsive force, it being one of the fundamental rules of electricity that equal and opposite quantities of electricity are always generated at one and the same time. So that if the Centrifugal Force is viewed as being simply the exact opposite of the Centripetal Force, it fully satisfies the test when the first two rules laid down by Newton are applied to it.

If, on the other hand, Centrifugal Force implies and embodies the idea of continuance of the Primitive Impulse, as I believe it is supposed to do, then to that extent it is not conformable to the principles of our Philosophy, as embodied in the rules given by Newton.

Simply because, while it supposes a source or origin of its activity at the first, it goes on to suppose a continuance of that activity, without recognizing a continuing source or cause. It only recognizes and supposes the one original impulse given at the beginning, to account for the cause of the continually existing, and exerted power of the Centrifugal Force. I do not for a moment suggest, that the Divine Creator of all things, and the Ordainer and Upholder of all powers, forces and laws could not, had He chosen to give such a force, have given it and for ever operating. With that aspect of the question I have nothing to do, and of it nothing to say. I am dealing, and only wish to deal, with scientific facts, and scientific teaching from the purely philosophical standpoint.

Such an idea of a continuing effect, without a continuing cause, is altogether opposed to experience and observation, and is a violation of the second Rule of Philosophy.

Look where we will, or at what we will, and not only effects and causes are seen on every side, and in every thing, linked together inseparably, but wherever, and in whatever phenomena there is found a continuance of effect or effects, there is always and without exception found also a continuing source or cause.

Wherever Nature, therefore, gives us a continuous effect of any kind or sort, she always gives us a continuing cause, that can be both proved and demonstrated to exist. Nowhere in Nature, amid all her powers, principles and laws, is there to be found an effect without a cause, and in all continuing effects, a continuing and perpetuating cause also, and that effect exists just as long as the cause exists.

If the effect is perpetual, then the source and cause is perpetual also, both in its existence and energy. Hence if the Centrifugal Force embodies the idea of continuance of the Primitive Impulse, without showing how that Primitive Impulse is continued, then such an idea is an anomaly in the universe, is altogether opposed to the teaching of Nature and science, and violates the most fundamental principles of our Philosophy.

The philosophic explanation, therefore, of the Centrifugal Force, is that Force which flows from a centre, and which is the exact opposite and counterpart of the Centripetal Force. Further, as the Centripetal Force is an attractive Force ever attracting to a centre, so the Centrifugal Force, being its exact opposite, is a repulsive Force, which fulfils all the laws and conditions which govern the Centripetal Force, as it is in every phase and aspect the exact opposite, being indeed its complement and counterpart.

Any physical explanation of the Law of Gravitation, therefore, must also give a satisfactory physical explanation of this Force, and show its mode of operation and working. This I premise I will do without the faintest shadow of doubt or failure; that is, if we are to accept the evidence of some of the most delicate experiments of modern times relative to aetherial physics.Art. 12. Laws of Motion.--One of the most important factors in the successful application of the Attraction of Gravitation to the universe at large, are the Laws of Motion enunciated by Sir Isaac Newton. These are three in number, and are as follows--

1st. Every body continues in its state of rest, or of uniform motion in a straight line, except in so far as it may be compelled by impressed Forces to change that state.

2nd. Change of motion is proportionate to the impressed Force, and takes place in the direction of the straight line in which the Force acts.

3rd. To every action there is always an equal and contrary reaction.

Corollary.--To these must be added the first Corollary of the three laws which is commonly known as the Parallelogram of Forces, which is as follows: “That when a body is acted upon by two Forces at the same time, it will describe a diagonal, by the motion resulting from their composition, in the same time that it would describe the sides of the parallelogram.”

Now let us apply Newton's Rules of Philosophy to these laws, and see if they fulfil the conditions laid down therein.

In the first place, there being three laws necessary to cover all the motions involved, there is not that simplicity of conception which is a primary factor in the making of any hypothesis. Then it will be observed that even after postulating the three laws, Newton was unable to account for the elliptic orbits of the planets, until he had added a Corollary known as the Parallelogram of Forces.Art. 13. Force.--The question has arisen also, as to the meaning of the term Force which Newton uses. What is a Force, its cause and mode of operation? The idea of Force is conveyed to us by our “muscular sense,” which gives us the idea of pressure, as for example when we push or pull a body along the ground.

We must not, however, limit our idea of Force to that narrow circle. It has now been fully established that Sound and Heat, Light, Magnetism, and Electricity are Forces, and therefore capable of doing work, as will be shown later on. Newton's use of the term Force is therefore somewhat vague; he does not definitely say what the Force is which causes the change of position, of the body, or of the rate of motion of that body. That it is something to do with Gravitation is obvious, but its exact nature or character is not revealed.

Since Newton's time we have made an advance in the definition of Force, and have come to consider Force as a kind of energy; the application of Force being the application of energy. Such terms as Mechanical Force, Chemical Force, Vital Force, are therefore out of date, and in their place the more definite ideas of energy are substituted. Instead, therefore, of getting such terms as Transformation of Forces, we now get Transformations of Energy. In the chapter on Energy, I hope to show that even that is not a satisfactory solution of the definition of a Force. If we are to make our Philosophy agree with our experience, then Force is due to motion, and motion alone.

So that Centrifugal Force will imply a motion from the centre; Centripetal Force a motion whose effect is ever towards the centre of gravity of any body.Art. 14. First Law of Motion.--This may naturally be divided into two parts for the purpose of applying the Rules of Philosophy.

(I) Every body continues in a state of rest, except in so far as it is compelled by impressed Forces to change that state. To what extent is this statement conformable to our experience and observation? If I place a body, as for example a weight, on a table, will it remain in that state until it is moved by some other Force? I think that it will so remain, and to that extent the law conforms to experiment.

Wider observation, and all experience, also prove the conformity of this part of the First Law of Motion to the second Rule of Philosophy, as all experience testifies to the fact that a body remains at rest, until some other power or force moves it from the position of rest. The application of this position of rest to any of the planets is, however, very difficult to conceive. MacLaurin, in relation to this fact, states: “This perseverance of a body in a state of rest can only take place in absolute space, and can then only be intelligible by admitting it.” In dealing with the physical cause of Gravitation, I hope to be able to show that it can not only be admitted as a mathematical proposition, but that it can be made intelligible from the physical standpoint.

The second part of the First Law of Motion may be stated as follows: “Every body continues in a state of uniform motion in a straight line, except in so far as it is compelled by impressed forces to change that state.”

Now what is the testimony of observation and experiment in regard to this part of the First Law of Motion? Let us test the question by the results of our experience. If a ball is sent rolling along the ground, its motion is gradually reduced until it comes to rest. If the ground is very rough indeed, as for example a ploughed field, then its speed will be very soon reduced, and the ball quickly comes to a standstill. If, however, the ground is smooth and level, like a well-kept cricket-field, then the motion of the ball will be reduced more slowly, and it will travel further before being brought to rest; while, if the ball is thrown along a very smooth surface of ice, it will travel a much longer distance before it is finally brought to rest.

Thus we learn, that the more we can get rid of all resistances to the motion of any body, the greater distance will the body travel, and the less diminution there is in the uniform motion of the body. So that, if it were possible to obtain a medium which offered no resistance at all to a moving body, then it would be a legitimate inference to infer that a body in such a medium, when once set in motion, would move with uniform motion for ever. Under such conditions, therefore, this part of Newton's First Law of Motion is physically conceivable. The crux of the whole matter, therefore, lies in the problem as to whether there is, or there is not, in existence, such a thing as a frictionless medium. We will therefore consider the problem of the existence of a frictionless medium from the philosophical standpoint.

Professor Lodge, in Modern Views of Electricity, p. 331, writes: “Now, if there is one thing with which the human race has been more conversant than another, and concerning which more experience has been unconsciously accumulated than about almost anything else that can be mentioned, it is the action of one body upon another; the exertion of Force by one body on another, the transfer of motion and energy from one body to another, any kind of effect, no matter what, which can be produced in one body by means of another, whether the bodies be animate or inanimate.”

“Now I wish to appeal to this mass of experience, and to ask, Is not the direct action of one body on another across empty space, and with no means of communication whatever, is not this absolutely unthinkable? We must not answer the question offhand, but must give it due consideration, and we shall find, I think, that wherever one body acts on another body by obvious contact, we are satisfied and have a feeling that the phenomena is simple and intelligible, and that, whenever one body apparently acts on another body at a distance, we are irresistibly impelled to look for the connecting medium.”

Again, on p. 333 of the same work, he adds: “Remember then, that whenever we see a thing being moved, we must look for the rope. It may be visible, or it may be invisible, but unless there is either a push or a pull, there can be no action.”

Now, in relation to celestial phenomena, we are confronted with the fact of bodies acting on one another, and yet apparently they do not act upon one another by or through a medium, and to that extent according to the above extracts, such phenomena are opposed to universal experience. Again, we find planets and satellites moving through space with more or less uniform speed, and yet apparently there is no physical medium that acts upon them with either a push or a pull, as the present conception of the Aether is that of a frictionless medium, so that experience in its widest form seems altogether opposed to the existence of a frictionless medium.

Again, Tait in his Natural Philosophy says: “The greater masses, planets and comets moving in a less resisting medium, show less indications of resistance. Indeed it cannot be said that observations upon any one of these bodies, with the exception of Encke's Comet, has demonstrated resistance. The greater masses, planets and comets moving in a less resisting medium, show less indications. No motion in Nature can take place without meeting resistance due to some if not all of these influences. The analogies of Nature and the ascertained facts of physical science forbid us to doubt that every one of them, every star, and every body of every kind has its relative motion impeded by the air, gas, vapour, medium, or whatever we choose to call the substance occupying the space around it, just as the motion of a rifle-bullet is impeded by the resistance of the air.”

What is the testimony of our own personal observation and experiments to such an impossible entity as a frictionless medium? Can any of the readers tell me of any medium, be it solid, liquid, or gaseous, that they have ever heard of, or read of, or experimented with, that possesses the quality of being frictionless? The answer is unanimously in the negative. But a frictionless medium was absolutely imperative to the success of the Newtonian aspect of the Law of Gravitation. If the Aether had not been frictionless, then the First Law of Motion would have been violated, and a body, as for example a planet set in motion, would not then have moved with uniform motion, but would have been brought to a standstill by the resistance of the Aether. Accepting therefore experience as a guide, as we are bound to do if we wish to be strictly philosophical, as Newton pointed out, then we are compelled to come to the conclusion that there is no such thing in the entire universe as a frictionless medium. Such a hypothesis is contrary to all laws and rules of Philosophy, and to continue to advocate its claims is to remain where we are in relation to the cause of Gravitation, and in complete ignorance of the beauty and harmony of the wonderful physical mechanism that underlies the whole of the universe. Of course, if experience and observation are no guide to Philosophy, then we will let imagination run riot, and postulate the most extravagant explanations for the varied phenomena of the heavens. With experience of no account, we will affirm that the moon is made of green cheese, that the earth is flat, that the sun revolves round the moon, and a host of other absurd hypotheses that require no correction by experience and observation. But there, a truce to such absurd imaginations. Experience is a guide to Philosophy, its claims are recognized by the greatest Philosopher the world has ever known, and therefore as either experience or a frictionless medium has to go, we will part with the frictionless medium, and endeavour to make a hypothesis of the Aether that is in greater harmony with our Rules of Philosophy.Art. 15. Second Law of Motion.--The application of Newton's Rules of Philosophy to the Second Law of Motion is attended with greater success than was the case with his First Law. “Change of motion,” he states, “is proportionate to the impressed Force, and takes place in the direction of the straight line in which the Force acts.”

Newton adds this explanation to his Second Law: “If a Force generates any motion, a double Force will generate double motion, and a triple Force triple motion, whether they are applied simultaneously or gradually and successively. And this motion, if the body were already moving, is either added to the previous motion, if it is in the same direction, or subtracted from it if directly opposed to it, or is compounded with the previous motion if the two are inclined at an angle.”

According to that, a force which presses or pushes with a four-pound pressure per square inch, if doubled, would press with a force of eight pounds per square inch, which fact agrees with experience. If the force is applied gradually, then the change of motion would be gradual; if applied suddenly, then the resultant motion would be sudden and violent.

The impressed force, therefore, always produces a definite and corresponding effect on any moving body, however that force may be originated, and however it may be applied. The effect so produced is always a change of motion, or, in present scientific terms, a change of momentum in the moving body. If the impressed force is halved, by an alteration in the mass of the body which exerts the impressed force, then the resultant momentum produced is halved also. If the impressed force is doubled, through any alteration in the velocity of the body which exerts the force, then the momentum produced in the moving body will be doubled also. So that the impressed force is equal to the change of momentum in the moving body upon which it is impressed.

When similar forces are impressed upon exactly similar bodies, the velocities produced are exactly the same; but, if similar forces act on dissimilar bodies, then the velocities produced in the different bodies are not the same; yet the total motion produced on all bodies, according to the Second Law of Motion, must always be proportionate to the impressed force. So that when we compare the effect of similar forces on different bodies, we find that there are two factors involved, viz., the mass and velocity of the moving body. The product of these two quantities is termed the momentum of the body.

When we apply the Second Law of Motion to the theory of aetherial dynamics, as suggested in this work, we shall seek to show that Newton's Second Law of Motion holds good in its application to the new theory. With the present conception of a frictionless Aether, however, it is philosophically impossible for the Aether to exert force on any body that may exist in it. Because, to the extent that it is frictionless, to that extent it ceases to possess mass. If it does possess mass, then it cannot be frictionless. Such an assumption violates all the Rules of Philosophy.

Yet the Aether is supposed, in some unknown manner, to possess inertia, which property is also dependent on mass. If the Aether really possesses inertia, then it must possess mass, and possessing mass it ceases to be a frictionless medium. So that if it possesses mass, then it can exert force the same as any other body, and Newton's Second Law of Motion is applicable to it.Art. 16. Third Law of Motion.--Newton's Third Law of Motion reads as follows--

“Action and re-action are equal and opposite, or, to every action there is always an equal and contrary re-action.” This law is also conformable to experience; for, by experiment, it has been proved to hold good for electric and magnetic action. As MacLaurin points out, the Third Law of Motion may be extended to all sorts of powers that take place in Nature, and belongs to attraction and repulsion of all kinds, and must not be considered as being arbitrarily introduced by Newton.

The mutual action between any two bodies has, therefore, a double action. Thus a piece of stretched string must be conceived as pulling at both ends; the pull at the one end being exactly equal and opposite to the pull on the other end.

A magnet will attract a piece of iron with a certain force, but it is equally true that the iron attracts the magnet with an exactly equal and opposite force. We might even extend the application of this Third Law to a falling stone in its relation to the earth. Thus, if a stone is dropped from a high altitude to the surface of the earth, although the motion seems to be all in one direction, yet if the Third Law holds good, then the earth is attracted by the stone in exactly an equal, but opposite direction, to that in which the earth attracts the stone.

As, however, the mass of the earth is very great compared with that of the stone, it follows that the velocity of the stone compared with the velocity of the earth, must be very much greater, in order that the forces shall be equal.

The application of this Third Rule of Motion to planetary and celestial phenomena is therefore philosophical, in that its conception agrees with experience and observation.

Thus, while it is true that the sun attracts each of the planets in his system, it is equally true that the planets, in their turn, attract the sun with an exactly equal and opposite force. But the velocity of motion induced by the earth's attractive power upon the sun, would be less than the velocity of motion induced by the sun's attractive power upon the earth, although the two forces would be equal and opposite, simply because force, being a compound quantity, is dependent upon the mass of a body as well as upon its velocity.

Not only, however, is it true that the sun and all the planets jointly attract each other, but it is equally true that the planets attract each other also, with an exactly equal and opposite effect. Indeed, as Gravitation is universal, it has to be conceived that there are no two bodies existing, but what the Third Law of Motion equally applies to those two bodies; so that equality of action and re-action is as universal as the Law of Gravitation itself.

In coming to a conclusion with reference to Philosophy and the Laws of Motion, I wish to say that I am strongly of the opinion that the day has come, or will soon come, when they will pass away and give place to a more direct and simple method of working of the great Law of Gravitation. I look upon the Laws of Motion as part of the scaffolding which has been used to build up the Law of Gravitation. That Law has now been erected, and stands firm and secure in its position in the universe. Whatever changes may take place in its scaffolding, the Law itself will stand out with greater beauty and clearness, if we could but see the perfected structure, apart from the props and helps which have assisted in its successful erection and completion. As Dr. Larmor said, in his address to the British Association, 1900: “There has even appeared a disposition to consider that the Newtonian principles, which have formed the basis of physical phenomena for nearly two centuries, must be replaced in these deeper subjects by a method of more direct description of the cause of the phenomena. The question has arisen, as to how far the new methods of aetherial physics are to be considered as an independent departure; or how far they form the natural development of existing dynamical science.”

I hope, therefore, to be able in this work to do something towards clearing the completed Law from some of the outside props, which have long hidden the simplicity, beauty and harmony of the physical working of Gravitation from the eyes of those who feign would see its wonderful mechanism.

In the elaboration and development, therefore, of the physical cause of Gravitation, it will be necessary to conceive a medium, whose properties and motions shall be able to account for all the movements of the planets, comets, suns and stars that the Laws of Motion now account for. Instead, however, of there being several Laws purely and simply mathematical in their application, there will be one physical medium, which will by its properties and motions account for--and that in a satisfactory manner--all the motions of the heavenly bodies. That such a medium is required in the scientific world is proved by the statement made by Professor Glazebrook, in his work on J. C. Maxwell, page 221, where he says: “We are still waiting for some one to give us a theory of the Aether, which shall include the facts of electricity and magnetism, luminous radiation, and it may be Gravitation.”Art. 17. Summary of the Chapter.--In summing up the contents of this chapter, we find therefrom, that there is a Universal Law in existence that is known as the Law of Gravitation. The physical cause of this Law, however, is unknown; Newton suggesting that it was due to the properties of an aetherial medium that pervaded the universe.

To form a right conception of this medium, and to develop the hypotheses of the same on strictly philosophical lines, it is essential for us to know the rules which govern the making of any hypothesis.

Those rules, according to Newton, and other philosophers, are chiefly three in number, and form the very essence of any philosophical reasoning. Any departure from those rules will entail partial or entire failure in the success of the undertaking.

The application of Newton's rules to parts of the great Law of Gravitation show that some of those parts are not fully in harmony with the rules which Newton laid down in his Principia.

Any physical theory that may be hereafter suggested as the physical basis for the Law of Gravitation, must itself not only account for the various forces already referred to, but must itself fulfil the Rules of Philosophy laid down by Newton. That is to say, the conception of the physical medium must be simple in character, its properties and motions must agree with all our experience, as given by observation, and experiments; and the properties and motions postulated for it must satisfactorily account for, and explain all the phenomena that are presented to us by the Universal Law of Gravitation.

If all this be done, then from the standpoint of strict philosophical reasoning, the physical medium so suggested, and the theory so made, will be incapable of being overthrown or disproved.