3 52 ANALYSIS OF THE GALVANIC PILE. 



because zinc is between two metals which have the same re- 

 lation with it in this respect; silver on one side, and the 

 brass of the tripod on the other side. The condition for 

 chemical effects in the circuit is also wanting ; as the wet 

 cloth is in contact only with silver. 



These conclusions with respect to the determined differ- 

 ence between the two kinds of groups, to which I was first 

 led by the above experiments, will be hereafter confirmed 

 by more precise phenomena, shown by new experiments di- 

 rected to that purpose; but I must first remove an apparent 

 Apparent con- contradiction between these experiments, and what had been 

 tradictionj determined by other experimental philosophers on the elec- 



trie states of zinc and copper when in mutual contact, 

 either metal It may be seen in the construction of the four different 



seeming m y represented in Fig. 2, that the succession of zinc and 



some cases po- r r ^ , . * f 



sitive, in others silver plates continues the same in all, throughout the whole 

 negative j length; from which arrangement, the termination of the 

 extremity A is by a silver plate, and that of the extremity 

 B by a zinc plate; at the same time it has been seen in all 

 the experiments made with these different piles, that the 

 extremity A is the positive, and the extremity B the nega- 

 tive. This seems to imply, that the silver side is the posi- 

 tive, and the zinc side, the negative ; whereas by other expe- 

 riments, silver is mgative, and zinc positive, when they are 

 connected together. Such- opposite conclusions from facts 

 equally certain much embarrassed me, til! by the study of 

 what is represented in Fig. 2, and the conclusions to which 

 it led me concerning the two different efficient groups, the 

 Tkldle was solved in the manner that I am going to ex- 

 plain ; which at the same time will be a confirmation of what 

 has been determined above, with respect to the groups. 

 explained. The condition of electric effects in the pile is absolutely 



this: the two metals, either in immediate contact, or con- 

 nected together by a metallic conductor; these groups being 

 separated by a non metallic conducting substance, here the 

 wet cloth : wherever therefore one of the metats is not in this 

 determined connexion with the other, it does not contribute, 

 to the electric effect oT the pile, but is an extraneous body. 

 Now, if notice be taken of all the piles represented in 

 Fig. ( 2, it wilL be seen, that the last piece of wet cloth, at 



the 



