120 A¥ALYSIS OF THE GALVAKIC TlLti. 



Apparatus de- end to the other. No. 2, is a first dissection of the pile by 

 scribed. . J 



the tripods, in which the latter divide it into ternary groups 



composed of the two metals and the wet cloth between them ; 

 this also prevails from one end to the other of the pile. 

 No. 3 represents the second dissection of the pile, in which 

 the tripods divide ternary groups composed of the two me-? 

 tals in mutual contact, and the wet cloth in contact with 

 nbeorlly; but this division not being complete at the ex- 

 tremities of the pile, this No. is represented in two part*; 

 one being the top of col. A, terminated by a silver plate 

 alone, and the other, the top of col. B, terminated by a 

 zinc plate with wet cloth. The case is the same in No. 4, 

 shewing the third dissection of the pile, in which the wet 

 cloth is in contact with silver: this representation also con- 

 sists of two parts, one being the top of col. A, terminated 

 by a silver plate with, wet cloth, and the other the top of 

 col. B, terminated by a zinc plate alone. In order to leave 

 place for th£ letters z and s near the plates, those of silver 

 are represented of the same thickness as the zinc plates, 

 though they were not so, as I am going to explain. 



In order that the frames of my columns might contain 

 the greatest number possible of groups when divided by the 

 tripods, I used very thin silver plates, these being very lit- 

 tle acted upon by the liquid during this kind of experi- 

 ments, each of which lasted only tjil the different effects 

 were observed ; but it is not the same with zinc, the surface 

 of which is soon calcined, and must be often restored to 

 the metallic state; so that, on account of the thickness of 

 the zinc plates, each column could contain only 3S groups 

 with the tripods, formiug a pile of 76 groups, the plates of 

 which were 1*6 inch diameter; and this remained the num- 

 ber of groups in all the following experiments, as far as re- 

 lates to this part. 



Lastly, as the different fiquids, wjtl) which t}ie pieces of 

 cloth may be imbibed, produce different effects, 1 deter- 

 mined to follow this first course of experiments with two 

 different liquids, namely, pure ivater, and a strong solu- 

 tion of marine salt, in order to compare their effects. Thus 

 I made two sets of the same experiments, in both of which 



1 began 



