171. Discussion. The electrification upon the ebonite is negative ([Exp. 60]). Although E S and E C ([Fig. 34]) seem quite smooth, there are many little hills, valleys, and air-spaces between them, which keep them from touching each other perfectly. The ebonite has[66] the electric field at the start, and it really acts across these minute air-spaces by induction ([Exp. 75]), and polarizes E C. The air-spaces form the dielectric ([Exp. 78]). The - electrification of E C being repelled by the - of E S, it is driven to the top of E C, while the + is drawn to the bottom. This + is kept from rushing to the - of E S by the air dielectric, and because E S is a non-conductor. By touching E C the free - escapes to the earth, leaving E C positively charged when it is lifted.
