13'Jf Professor Schoeuhe'm^s/uriher Experiments 



Sixth Fact, — If the four electrodes of two piles (each con- 

 sisting of about half a dozen of pairs of zinc and copper) be 

 introduced into two vessels containing common nitric acid, in 

 such a manner that the positive electrode of one pile and the 

 negative one of the other dip into the same vessel, and the 

 oxidized end of an iron wire be plunged into any of the ves- 

 sels, and its ordinary end afterwards into the other one, the 

 latter becomes inactive, just in the same way as if the two vessels 

 were connected by a copper wire. But to obtain this result 

 it is requisite to bend up the second, that is to say, the or- 

 dinary end, thus ~Xy previously to immersion. 



Now, why does F in the first case not become inactive by the 

 current produced by its being plunged into B? It seems to 

 be an indispensable condition for calHng forth the inactive state 

 in iron, that at the moment of its being immersed into the acid, 

 a current of a certain energy should be passing through it. The 

 current produced by the part of the metal immersed, is of 

 sufficient strength w^hen both ends of the iron wire plunge 

 into the acid contained in only one (small) vessel ; but when 

 this same current has to pass through the acid of two vessels, 

 and besides to enter and issue into and from the connecting 

 platina wire, its strength is diminished below the degree ne- 

 cessary for producing the effect in question. But if this way 

 of accounting for the fact be correct, it may be asked, how it 

 comes, that with a connecting wire whose ends are attacked 

 by the acid of the vessels, different results are obtained? It 

 is obvious, that in the second case, two currents moving in 

 opposite directions and originating in C and D are established, 

 as soon as the iron wire E F has connected the vessels A and 

 B. Besides these currents, a third one is produced by the 

 immersion of F in B. But this current having to move the 

 same way which the current in the first case must pass, why 

 is its effect different from what that of the latter is ? Now 

 it seems to me, that if two currents of opposite directions cir- 

 culate through our circuit of the second case, they remove in 

 some way or other the obstacles which the third current 

 (in itself of weak power) would have to overcome, if it were 

 moving alone through the circuit; or in other words, if two 

 opposite currents cross the nitric acid, its conducting power 

 for a third current is increased. In the third case, there are 

 likewise two opposite currents established, as soon as F dips 

 into B; one produced by C, the other by E ; and there is again 

 a current excited by F, which must be considered as the cause 

 of the peculiar state of this end. It is only to be wondered at 

 why D, when having been made inactive by immersion in 

 strong nitric acid, or by the help of platina, is not rendered 



