ACCUMULATORS. ' 85 



The electricity, on the positively electrified coating, 

 slowly penetrates into the glass, acting inductively on 

 its electricity, which it repels from the opposite sur- 

 face ; and producing, probably, a temporary strain or 

 distortion of its structure. 



When the first discharge takes place, there 

 is a relief from this strain; and, as the 

 electrified glass slowly returns to its former 

 state, the electricity which had penetrated it 

 returns to the conducting surface. 



This view receives confirmation from the 

 fact that delay increases the residual charge, 

 giving time for the electricity to come out of 

 the glass and accumulate : while it has the 

 opposite effect on the primary charge, reduc- 

 ing it by giving time for dissipation. 



Tapping the jar lightly hastens the in- 

 crease of the residual charge, the vibratory 

 motion thus given to the glass tending, prob- 

 ably, to relieve the electric strain. 



JAB WITH MOVABLE COATINGS. If a with 2 



Leyden jar be constructed Avith any rigid Coatlu s s - 

 metal, as sheet brass, for both coatings, as suggested on 

 page 76, and the conducting rod be attached to the 

 inner coating, the coatings may be removed and re- 

 placed at pleasure, as represented in Fig. 24 : and we 

 have the means of investigating certain phenomena in 

 regard to the electrification of the different parts. 



Let a charge be given to such a jar, and the coatings 

 removed carefully, so that they shall not be connected 

 by a conductor during removal: they may now be 

 brought into contact without producing any electric 

 effect ; and the jar also may be handled with a like 



