40-t M. Becquercl on the Electric Effects 



of water. A plate of platinum exhibited absolutely the same 

 results. May not these phsenomena have some distant re- 

 lation to those observed by MM. Thenard and Dulong in 

 their researches respecting the property which certain bodies 

 possess of favouring the combination of elastic fluids? These 

 two celebrated philosophers found that a fresh wire of platinum, 

 which did not become heated at the ordinary temperature, 

 when it was placed under a current of hydrogen gas, which 

 diffused itself in the air, became susceptible of becoming red- 

 hot, when it had previously been plunged in nitric acid for 

 some minutes, and the excess of acid taken away. The pro- 

 perty that the platinum wire then acquires, lasts more than 

 twenty-four hours. We remarked that a plate of gold pre- 

 served for several hours the property of becoming strongly 

 electric in its contact with the water. — We propose to return 

 to these phaenomena, which we only indicate here. 



Electric Effects observed in the Contact of two Metals with a 

 Eiqxdd. 



We have already said, that the electric effects which mani- 

 fested themselves when two metals were separated by a liquid, 

 were not similar to those which took place when the liquid 

 was replaced by any metal ; for Volta found that, in this 

 last case, the intermediate metal served only as a conductor ; 

 whereas we have shown that this did not take place in the 

 other. It is very probable that the electric tension of each 

 metal is here owing to a difference of action. Let us then 

 admit this principle until experience has proved that it is not 

 correct. Let us take, for example, copper and zinc, and 

 let us represent the electric tensions of the copper and of the 

 liquid, by + Sand — 8, those of the zinc and of the same liquid 

 by + 8' and — 8' ; the electricity 8 of the liquid will be com- 

 mon also to the zinc, as the electricity 8' will be to the copper. 

 It will follow that the electric tensions of the copper and the 



zinc will be H — and -\ — . 



Thus, according as 8 shall be greater or less than 8', the 

 electricity of the copper will be positive or negative, whilst 

 that of the zinc will be the contrary. All leads to the sup- 

 position that such is the case. 



The following table includes the results of a number of 

 experiments. 



Metal 



