wax. 



10 feLECTRIC EFFECTS OF FRICTION. 



paired its losses from my finger, the cylinder, wlieb received 

 more Jiuid, coinmiinlcuting- thns more oF it to the prime 

 conductor, that quantity became sensible to the electroscope 

 11. The glass rubber, undergoin'^ these losses, was at 

 every instant rendered negative, but not in a perceptible 

 manner, because its losses were also instantly repaired from 

 my linger, which, beinj^ in the way, prevented the elec- 

 troscope 11 from showing this state. 

 Fxp. 4. Exp, 4. I covered with sealing wax the under part of 



Fiiction be- the extremity 1 6 of a brass rubber, similar to that of 

 and sealing Exp. 1, and made the wax rub the glass cylinder; this 

 produced a little divergence in the electroscope 11, which 

 was positive, but none in the electroscope 19. This at first 

 appears contrary to the above lavv, namely, that one of the 

 bodies, which ruh each other, can acquire some electric 

 fluid only by taking it from the other, which must become 

 negative. But afterward 1 considered, that the sealing 

 wax, here a mere lamina, covering the 6rff55 spring, being 

 impermeable to the electric fluid, the quantity carried off 

 by the glass cylinder from its free surface could not be 

 repaired through it by the brass, which therefore lost no 

 sensible quantity of the fluid. In consequence of this idea, 

 1 changed the rubber in the manner represented by the 

 Reparate^^^. A. A piece of sealing tvax about i of an inch 

 thick, cut underneath so as to fit the glass cyhnder, is held 

 in its upper part by a doubled piece of thin brass (one side 

 of which is seen in 2) ; and on its top is soldered a brass 

 spring 3, .the opposite end of which is placed, as usual, in 

 the brass piece 13, communicating with electr. 19. By 

 this construction, while the sealing wax loses sonae electric 

 fluid to the glass cylinder which revolves against it, this 

 loss is repaired by the fluid proceeding from the brass (as 

 from 2, tig. A), moving along the side of the piece of 

 sealing wax, which thus is enabled to yield more fluid to 

 the glass cylinder. Thus the electroscope 1 1 has a much 

 greater positive divergence than before, and the electro- 

 scope 19 has now a great negative divergence, because the 

 brass spring, communicating with it, loses some electric 

 fluid, by yielding it to the pealing wax, 



Exp, 5* 



