VoJla on Animal Eie3rictfj/» rt^J 



"With fome metals there is, however, a confiderable deviation 

 rrom this order, in regard to livers of fulphur, alcaline fluids, 

 and the nitrous and faline acids. 



As to the metals, which in their pofition between thefe 

 different fluids are more or lefs proper for the ele6lric efie*3: 

 in queftion, I have found in general that tin exceeds all 

 others, and that filver is the word ; except when one of the 

 fluids betwixt which the filver is placed is water, or any 

 other aqueous conductor, and the other liver of fulphur : in 

 this cafe filver far exceeds zinc, and even tin. Iron alfo 

 produces a much greater effeft than any other metal, when 

 it is in conta6l, on the one fide, with mere water or an aque- 

 ous conductor, and on the other with the nitrous acid, were 

 it even only a drop. The excitement occafioned in both 

 cafes is wonderful j fince it exceeds, as I have already re- 

 marked, that produced, according to the ufual method, by 

 means of a double metallic bow, even of different metals, as 

 zinc and filver, applied to condu£lors of the fecond clafs of 

 the fame kind. It is fufficiently ftrong and powerful to pro- 

 duce convulfive movement in a half-prepared frog, the bowels 

 of which have not been taken out, when one of the two moift 

 conductors is a concentrated alcaline folution, and the metal 

 placed between them is zinc, or rather tin. With other 

 metals and other fluids you can fcldom produce convulfions 

 in a frog, if it be not perfectly prepared, or at leail em- 

 bowellcd. 



The reader will readily perceive, that when a bow of one 

 and the fame metal touches with both its ends the fame kind 

 of faline water, the fame acid, the fame alcaline fluid, &c. an 

 cledtric ftream will not take place, as happens alfo when it 

 touches on each fide merely water: in that cafe two oppofite 

 auctions are oppofed to each other, and keep each other in 

 equilibrium. That the(e contrary powers, however, may be 

 in perfect equilibrium, it isneceflkry that the fluids applied to 

 both ends of the homogeneous metalline bow be cxaftly of 

 the fame kind and of the fame ftrcngth. For this reafon the 

 M3 moft 



