The conclusion I have come to is that non-conductors, as well as conductors, have never yet had an absolute and independent charge of one electricity communicated to them, and that to all appearance such state of matter is impossible.
Again (Arts. 1177 and 1178), as far as experiment has proceeded, it appears, therefore, impossible either to evolve or make disappear one electric force without equal and corresponding change in the other. It is also equally impossible experimentally to charge a portion of matter with one electric force independently of the other. Charge always implies induction, for it can in no instance be effected without; and also the presence of the two forms of power, equally at the moment of development and afterwards. There is no absolute charge of matter with one fluid; no latency of a single electricity. This, though a negative result, is an exceedingly important one, being prob ably the consequence of a natural impossibility, which will become clear to us when we understand the true condition and theory of the electric power.
The preceding considerations already point to the following conclusions: bodies cannot be charged absolutely, but only relatively, and by a principle which is the same with that of induction. All charge is sustained by induction. All phenomena of intensity include the principle of induction. All excitation is dependent on or directly related to induction. All currents involve previous intensity and therefore previous induction. Induction appears to be the essential function both in the first development and the consequent phenomena of electricity.
From this point of view, the charges of A and B in the above experiment were merely manifestations of some condition in the medium between A and C and between B and D. If A assumed a larger proportion of the total electrification than B, it was because induction took place more freely between A and C than be tween B and D. Faraday accordingly said that sulphur had a greater capacity for electrical induction than air, and that if the inductive capacity of air were taken as 1, the inductive capacity of sulphur would be greater than 2.24.
It may be interesting at this point to consider briefly the difference between the views of Cavendish and Faraday. Cavendish believed all bodies to contain an unknown quantity of a single electric fluid, and that this fluid was always under some kind of external pressure and that in conductors it always flowed toward the region of least external pressure and could be in equilibrium only when the external pressure was everywhere the same over the surface of the conductor or system of conductors in which the fluid was confined. From his point of view, the reason that A took a greater charge than B in the Faraday experiment was that the external pressure on a given charge was less around A than around B, and hence that an excess of fluid would flow into A until this external pressure was equalized upon the fluid in the two spheres.
Faraday attributed the state known as electrification not to any changed condition inside the charged conductor, but wholly to
