1 70 Prof. Schoenbein on the Theory of Gahanism. 



about which I must offer some remarks. If two pieces of iron 

 wire, one of which is to be inactive, the other in its natural con- 

 dition, are connected with a galvanometer, and the free end 

 of the former first put into common nitric acid, and afterwards 

 the free end of the oi'dinary wire, it is well known from my 

 former experiments that the latter piece of wire becomes in- 

 active, and that at the same time a current is produced which 

 passes from that wire through the acid into the inactive one. 

 The latter wire, therefore, is to the common one as platina is 

 to zinc. Such a state of things, however, lasts only for a few 

 moments, the voltaic difference of the two iron pieces disap- 

 pearing very quickly. If in the experiment described the or- 

 dinary iron wire be first plunged into the acid, the inactive 

 one is thrown into chemical action, and a current excited, to 

 which the latter wire acts the part of the cathode ; but no 

 sooner has the passive iron been rendered active, than the cur- 

 rent ceases, or rather current-equilibrium is established. Now 

 if chemical action has nothing to do with the production of cur- 

 rent electricity, why does the order in which our wires are 

 plunged into the acid determine the results spoken of? Ac- 

 cording to Fechner's views, inactive iron ought to remain in 

 its peculiar condition, whether it be put before or after the 

 ordinary wire into the fluid ; and the more should this be the 

 case, that the Saxon philosopher does not seem to admit of the 

 existence of any causal connexion between a current and the 

 inactivity of iron, making the latter depend upon a peculiar 

 action of nitric acid or nitrate of silver on that metal. I 

 scarcely need to mention, that the same principle made use of 

 to account for the phaenomena to which iron associated with 

 copper gives rise in a solution of blue vitriol, is perfectly ap- 

 plicable to the facts just now stated ; and I should think that, 

 according to the present state of science, no other account of 

 them can be given. In the experiments described, chemical 

 actions and voltaic effects appear, indeed, so closely connected 

 with one another, that an unbiassed mind can hardly help 

 considering the first as the cause of the latter. 



I have perhaps enlarged too much upon my subject, and am 

 really afraid of being chargeable with prolixity ; but as the dis- 

 cussion into which I have entered regards the very first prin- 

 ciple of the chemical theory of galvanism, I thought I could 

 render some service to science by minutely appreciating the 

 value of the objections which have been brought forward 

 with the view of invalidating or rather overthrowing the che- 

 mical theory. 



Up to this present moment I have considered the definite 

 action of an electric current, and the fact, that the quantity of 

 the latter produced by an hydro-electric arrangement is deter- 



