38 HISTORY OF GALVANISM. 



because the zinc has the copper plate on one side, 

 and the wire frame on the other, which have the 

 same electrical relation to the zinc, and therefore 

 counteract each other. 



File of sii- The different effects which seemed to ensue, be- 

 pewter. tween the pile when furnished with pure water, 

 and with the solution of a neutral salt, induced 

 De Luc to examine what connexion existed be- 

 tween the oxidation of the zinc, and the chemical 

 action of the instrument. For this purpose he 

 formed a pile of silver and pewter, the pewter 

 being selected for the experiment, because it has 

 an electrical relation with silver, and is oxidable 

 by muriatic acid, at the same time that it is not 

 much affected by pure water. In the first instance, 

 water was interposed between the plates ; the ex- 

 tremities of the pile, as indicated by the electrome- 

 ter, became electric, the pewter side negative, and 

 the silver positive ; but there was no shock, nor 

 any decomposition of the water in the interrupted 

 circuit. A pile was then formed of such a num- 

 ber of zinc and silver plates, that its electrical 

 energy might be the same with the pewter pile ; 

 but here there was both the shock produced, and 

 the decomposition of water. The pile of pewter 

 and silver was then fitted up with muriatic acid ; 

 and in this case, when the pewter plates became 

 oxidated, the shock and the decomposition of 

 General water were both produced. From these experi- 

 ments, the author deduces the following con- 

 clusions. When the metal is not oxidated, no 



