Let A be an electrified body (Fig. 13), and C be a body not electrified, but situated within the electric field of A. Then it can be experimentally proved, that C will also become an electrified body by induction. As is well known, there are two kinds of electricity, Positive and Negative. We will suppose A to be charged with positive electricity. Then it can be proved that C will also be charged with negative electricity on the half nearest to A, while the other half will be charged with positive electricity.
Now how has this result been brought about? According to Faraday's theory the particles of air, the dielectric, between A and C play a most important part in the process. As a matter of fact, each atom or particle of air is polarized, as the process of separating the two kinds of electricity is termed, so that every atom has one half of it covered with positive electricity, and the other half with negative electricity.
For example, let A and C be the same brass balls with the particles of air between them, A being the positively charged ball and C the unelectrified ball, the shaded parts representing positive electricity and the unshaded parts negative electricity.
Then A will act inductively on the unelectrified ball C through the medium of the particles of air d, e, f, g, h. The electrified ball A will act first on the layer of particles next to it, attracting their negative electricity and repelling the positive according to the well-known law that “Unlike electricities attract, like electricities repel each other.”
The positive electricity in the first layer then acts in the particles of the next layer in the same way, and thus the inductive action is transmitted through the particles, from layer to layer, until we come to the last layer of particles next to the ball C.
As the half of each atom or particle nearest to C is positively electrified, then the half of the ball C nearest to the layer becomes negatively electrified, while the half further away is positively electrified. Thus we say that C has become electrified by induction through the polarization of the particles of air which lie between the two bodies. Faraday on this point says: “Thus induction appears to be essentially an action of contiguous particles, through the intermediations of which the Electric Force, originating at a certain place, is propagated or sustained at a distance, appearing there as a Force of the same kind exactly equal in amount, but opposite in its direction and tendencies.”[27]
While again he states:[28] “Induction appears to consist in a certain polarized state of particles into which they are thrown by the electrified body sustaining the action, the particles assuming positive and negative parts which are symmetrically the lines of Inductive Force.” Thus in the case of any electrified body, acting on an unelectrified body at a distance, it has to be definitely understood that the action at a distance is alone communicated and propagated by the dielectric or medium which exists between the two bodies. Though in the case of Gravitation it has been mathematically assumed, that action at a distance is possible, yet experimentally and physically such an assumption is philosophically incorrect, as all experience and experiment go to prove that there is no such thing as action at a distance manifested, except such action is propagated through the intervening medium, as stated and proved by Faraday.
In order to bring Gravitation, therefore, into line with our experience, it will have to be demonstrated that it, too, is the result of the action of the intervening medium, that is, the Aether, which is a result we are being led up to.
We have already seen that the sun is an electrified body, possessing an electric field, and as all electrified bodies can act on other bodies in their field inductively, then a similar result should happen in the solar system, that happens in any electrical experiment on induction, with the result that all the planets should become electrified bodies by induction, such action taking place, as Faraday points out, through the medium which divides the sun and the planets, that is, the Aether.