UNIVERSITY 



ELECTRIC CONDENSERS. 



ductor, for obvious reasons. But if two conducting plates, 

 A and B, separated by a non-conductor, C, be connected 

 c with, the prime conductor, and 



the plate, A, provided with a 

 ground connection, as shown 

 in Fig. 149, the charge of B 

 will be more intense than that 

 of the prime conductor; its 

 tension will be greater than 

 that of the charging body. If 

 a third plate like B, but having 

 V :!:::: ,,..,.,.,::,. no opposite plate like A, be 

 Hi connected with B by a copper 

 wire and the middle of the wire 

 brought into contact with the 

 prime conductor, nearly the whole charge will go to B and 

 very little to the third plate, which has no condenser like A. 



FIG. 149. 



352. Electric Condensers. The electric condenser is a 

 contrivance by which the tension 

 of the body charged may be made 

 greater than the tension of the 

 body charging. Let A and B, 

 Fig. 150, represent two insulated 

 metallic plates about six inches in 

 diameter, separated by C, a plate 

 of glass somewhat larger. Let 

 each metallic plate have an elec- 

 tric pendulum, a and b. Remove 

 A, and connect B with the con- 

 ductor of the electric machine. 

 The divergence of b shows the presence of free electricity. If the 

 wire x were now cut, no change would take place. Connect A with 

 the ground by the wire y, and place in position as represented. By 

 the inductive influence of B, the neutral electricity of A is decom- 

 posed, its negative electricity being drawn to the surface n, while 

 the positive escapes by y. But this negative electricity at n attracts 

 the positive of B largely to the surface m, and holds it there as 



FIG. 150. 



