Page:Scientific Memoirs, Vol. 2 (1841).djvu/449

 VOL. II.—PART VIII.

continued.

A. General observations on the diffusion of electricity.

1. of bodies, called into activity under certain circumstances, and which we call electricity, manifests itself in space, by the bodies which possess it, and which on that account are termed electric, either attracting or repelling one another.

In order to investigate the changes which occur in the electric condition of a body $$A$$ in a perfectly definite manner, this body is each time brought, under similar circumstances, into contact with a second moveable body of invariable electrical condition, called the Electroscope, and the force with which the electroscope is repelled or attracted by the body is determined. This force is termed the electroscopic force of the body $$A$$; and to distinguish whether it is attractive or repulsive we place before the expression for its measure the sign + in the one case, and – in the other.

The same body $$A$$ may also serve to determine the electroscopic force in various parts of the same body. For this purpose we take the body $$A$$ of very small dimensions, so that when we bring it into contact with the part to be tested of any third body, it may from its smallness be regarded as a Rh