ATTRACTION AND REPULSION. 3 



Let the pith balls be separated at the points of sus- 

 pension, so that when they hang vertically a consider- 

 able space shall intervene between them, and let a 

 stick of sealing-wax, previously electrified by friction, 

 be brought near one of them ; the ball will.be attracted 

 to the wax, and, after a momentary contact, repelled. 

 Follow it with the wax, and it continues to recede as if 

 pushed back by some invisible barrier. 



Now let the other pith 



ball be moved near this / v 



one, and they will be ' ' 



attracted to each other, 

 and, after contact, re- 

 pelled ; the lines of sus- 

 pension showing diver- 

 gence in each direction 

 as represented. 



Let the electrified wax 

 be again brought near, 

 and each ball is repelled 

 by it, so that when it is Fi ' 2 ~ T " e Pk "- Ba!1 Electroscope, 

 placed between them, they are driven further apart ; 

 but let any non-electrified body be brought near and 

 they are attracted to it. 



If each of the balls be separately electrified by the 

 wax, and they are then brought near each other, they 

 will show mutual repulsion without previous attraction. 

 "From this series of phenomena we learn, first, that 

 electrified bodies not only attract non-electrified bodies, 

 as already shown, but communicate electricity to them 

 by contact ; and, secondly, that bodies electrified, either 

 by each other or from the same source, show mutual 

 repulsion. 



