It will be interesting to find out, what law governs the intensity of this force in any part of the field, or at a given distance from the central body. We have seen (Art. 66) that the law governing the intensity of heat at any distance from the sun, is the law of inverse squares. Further, from Art. 75 we have also learned that light is subject to the same law of inverse squares, as indeed it should be, if it be due to one and the same medium, the Aether. If, therefore, electricity is also due to certain motions of the aetherial medium originated by the action of an electrified body as the sun, in the same way that light and heat waves are originated, then it ought to follow that the repulsive power of electricity is also subject to the same law of inverse squares. As a matter of fact, that is exactly the state of affairs, so that we find the intensity of the repulsive power in the Aether from any central body, due to the electric waves, or the pressure due to the wave motions of the electric Aether, in relation to that body, is governed and controlled by the same law that governs light and heat. It may be suggested that such a coincidence is not a very strong argument, as all forces emanating from a central body are subject to the same law of inverse squares. In reply to that, I should like to point out, that even that objection only strengthens the conception of the Aether that we are endeavouring to complete. Our contention is, that all physical forces, whether they be light, heat, electricity, magnetism or Gravitation, are all due to the motions of the aetherial medium; which motions may be generated by a heated or luminous or electrified body, and are radiated from such a body in waves of concentric spherical form, and are all subject to the laws of inverse squares. So that the fact of the intensity of the centrifugal force due to the repulsive power of electricity falling into line with the law governing light and heat is, to my mind at any rate, only a clearer proof of the one common origin of all the physical forces. The law of inverse squares in relation to electricity may be thus stated. The Centrifugal or Repulsive Force between two charged electrified bodies acts inversely as the square of the distance between them. This law was proved by Coulomb by means of an instrument known as Coulomb's Torsion Balance, and I must refer the reader to any work on electricity for a full establishment of this law. Suffice to say, that it has been experimentally demonstrated that the law holds good in relation to the phenomena of electricity; and, wherever we get the two kinds of electricity present in any medium or conductor, owing to the polarization of its particles, there we have this law operating in relation to the intensity of the repulsions of the two bodies directly concerned.