503 Report to the French National Injiitute 



Volta employed them for the eftabliflnnent of his theoty. 

 It is much indebted to that learned man for the readinefs 

 with which he repeated them, feveral times, before the com- 

 miHioners ; who can thus vouch for their truth and correcl- 

 nefs. The principal fa6l, that from which all the reft majr 

 be deduced, is as follows : 



If two diflcrent metals, infulated, and having only their 

 natural quantity of eleftricity, are brought into confaft, 

 when removed from that contaft they are found in diBcrent 

 ttates of electricity : one is pofitive, and the other negative. 



This difierence, very fmall at each contact, beins; accu- 

 mulated in an electric condenfer, becomes fufficicntly ftrong 

 to caufe the ele<itrometer fenfibly to diverge. The action is 

 not exercifed at a diftance, but only on the contaft of dif- 

 ferent nietals ; it fublilts as long as the conla6t continuesj 

 but its intenfnv is not always the fame. It will here be fuf- 

 ficient to take as examples copper and zinc. In their mutual 

 contact the copper becomes negative, and the zinc becomes 

 potitive. 



Havintr proved the development of metallic clet'^ricity in- 

 dependently of any moill conduftor, C. Volta introduces 

 ihefc conductors. 



If a metallic plate be formed of two pieces, one of zinc 

 and the other of copper, foldered end to end; if the ex- 

 tremity of the zinc be held between the fingers; and if the 

 other, which is of copper, be made to touch the upper plate 

 of the condenfer, which is alfo of copper, the latter Avill be 

 charged negatively. This is evident from the preceding ex-f 

 perirnent. 



On the other hand, if the copper extremity be held be- 

 tween the fingers, and if the other cxtreniltv, which is of 

 zinc, be made to touch the upper plate of the condenfer, 

 which is of copper, when the contact is deftroved, and the 

 upper plate is removed, it has not acquired eleCtricitv, though 

 the lower plate communicates with the common relcrvoir. 



But if paper moiftened with pure water, or anv other moid 

 conductor, be |)laced between the upper plate and the zinc 

 extren)ity, the condenfer becomes charged with pofitive elec- 

 tricity. It become? charged alfo, but negatively, when the 

 upper plate, covered with a moifl: conductor, is touched by, 

 the copper extremity, holding the zinc* extremity betweeii 

 the fingers. Thefe fafts are inconteltable ; they have been 

 verified by the com million. 



The manner in which C. Volta explains them, and refers 

 them to the preceding, is as follows : 



Metals^ fays ne, and peihaps all the bodies in nature, 



cxercife. 



