

ANALYSIS OF THE GALVANIC PILE, ] 33 



the extremity of each of them, leaves above it one of the 

 metals unconnected with the other, so that the former there- 

 fore is a mere conductor to the electroscope. Thus the effi- 

 cient groups for electric effects terminate at and under that 

 piece of cloth ; and it may be seen in the flgure, that in this 

 manner zinc terminates the extremity A, which is positive, 

 and silver the extremity B, which is negative; and thus, 

 not only the two experiments are reconciled, but thereby 

 the definition of these groiips in the pile is confirmed, 



Another phenomenon manifested in these experiments Without oxt- 

 deserved a farther investigation, in order to avoid any mis- ^ tion of the 

 . ° T i i P lates no shQcjc 



take; as it leads to important conclusions* It has been produced. 



seen, that, when the pieces of cloth were imbibed with 

 pure water only, though chemical effects were produced in 

 the glass tubes, there was no shock; but that this effect was 

 produced, when the calcination of the metals in the pile was 

 effected by the acid of marine salt. It was therefore im- 

 portant to know, whether this particular cause of calcination 

 were an accidental, or necessary condition of the shock; and 

 I thought of a way to decide it, which was, to substitute 

 for zinc a metal, which, becoming positive with silver, and 

 thus capable of producing a motion of the electric fluid, 

 should be calcinable by the acid of marine salt, but not by 

 pure water; I found pewter to be such a metal, and I made 

 the following experiments; first by my condenser so con- 

 structed, that 1 could readily try the effect of small piles, 

 placed on a conducting pillar, lifted up by a string against 

 a brass bull projecting from the receiving plate, and which 

 descends by its own weight when the string is relaxed. 



Exp. 15. I tried in this manner a pile of 20 groups, pew- Exp. 15. 

 ter and silver, separated by cloth imbibed with pure water, Pewter an«Uil- 

 and I found, that the pewter side affected the condenser 

 positively and the silver side negatively in sufficient degrees, 

 to give hope, that, by increasing the number of groups, im- 

 mediate electric signs would be produced in the electro- 

 scopes at the extremities of the pile, 



Exp. 16. I procured thin pewtet plates the size of my E xp . |k 

 silver plates, and I increased the number of these binary 

 groups, separated by pieces of cloth imbibed with. pure wa- 

 ter, till I had sufficient electric signs at 'the extremities: this 



was 



