()4 ELECTRICAL EXPERIMENTS ON GLASS. 



an experiment He takes an elcctrophorus, places it on an insulating 

 tr© th h^u, elCC " st:inJ » at,( * insulates himself before he rubs it. In this state 

 of complete separation from the ground he excites it by- 

 friction, touches the two coatings, and obtains sparks as 

 strong as if both he and the electrophorus had a communi- 

 cation with the ground. Hence he concludes still, that 

 the double contact, necessary as he says, establishes a 

 complete circulation, as in his experiment with the phial. 



The experi- There is a more simple mode of making this experiment 

 ment; made in . , „ , . . , , , ,, . . , 



another way. Wlt " a sn i' d »l curved exciter with a glass handle. I take an 



electrophorus completely insulated ; I rub it in a state of 

 insulation like the Dutch philosopher; I quit the insulating 

 stool and take the exciter, the two coatings of which I 

 touch at once with its knobs ; and I not only obtain a spark, 

 but taking the exciter, leaving one of its knobs on the ex- 

 ternal coating, and raising the other four or six inches so 

 as to lift the cap to it in the air, a real discharge takes place. 

 On laying down the cap without a fresh contact, scarcely 

 does it give a very feeble spark. The beautiful experiments 



Electricity of Mr. Libes, in which he obtains electric fluid by the mere 

 fiomtheron- «'■»•«» i 



tact of different contact of different metals, evidently prove to me, that 

 metals. here, where the action is triple, or between two metals and 



rubbed resin, there is a real generation of igneous matter, 

 if I may so express myself, which is renewed at every dou- 

 ble contact. The following experiment is calculated to sup- 

 port my conclusion. 

 Sparks from I had seen in the Electrical Phenomena of Mr. Sigaud 



the mouldings d j Fond, that some gentleman observed the silt mould- 



ot a chest of ' ° t ° 



d-.awers when ings of a chest of drawers to emit sparks every time he drew 



onetakenfrom one . from the cap of an electrophorus accidentally placed 

 an electropho. . r r . J \ 



iusuponit. on it*. This tact led me to make the experiment with an 



insulated electrophorus; by the side of which I placed a 

 copper ball having a rod that communicated with the 

 ground. This ball was about a line from the outer coating; 

 and I stood on an insulating stool when I took a spark. In 

 this state, to prove that it is no circulation that occasions 

 the discharge, but an attraction of the ground, which be- 

 comes divellent at the moment when the fluid retained in 



* Phenomenes Electriq/ic;, p, G7B, § 174. 



the 



