370 G. Th. Fecliner's Justification of the 



power of opposing the transfer of electricity. (Compare with 

 No. 3.) I cannot find the least proof in this experiment. From 

 the same point of view we must also consider the experiment 

 published byDe la Rive in these Annalen^lxoi. xl. p. 368. If 

 I say that iron also undergoes a change of the same kind in 

 caustic potash, that it becomes considerably more negative by 

 its action than before, all that is there stated appears to me 

 explained, although the change of the iron itself may still 

 need an explanation not less when regarded according to the 

 chemical theory than to the theory of contact. Among other 

 circumstances, we find a proof of this change, that iron con- 

 nected with copper in caustic potash to form a circuit, at first 

 gives the normal divergence of the multiplier, which diver- 

 gence makes the iron appear positive, but shortly after it 

 changes. That, however, iron gives no current with platinum 

 in caustic potash 1 did not find to be the case. On apply- 

 ing a very delicate multiplier the current was strong enough 

 to place the double needle almost perpendicular to the 

 coils. 



3. The following experiments belong to those which at first 

 sight appear most strikingly to favour the chemical theory, 

 and to which its supporters attach especial importance. Zinc 

 with copper gives in distilled water, as also in concentrated 

 sulphuric acid, closed, only weak electric currents ; in diluted 

 sulphuric acid, a mixture of both fluids, very powerful ones. 

 Since it is not probable that the proper conducting power of 

 the fluids is changed by their mixture, there remains nothing 

 more than to attribute the increased current to the increased 

 chemical action which takes place on diluting the sulphuric 

 acid, which produces the increased development of electricity. 

 Similar to this is the Ibllowing experiment: platinum with 

 gold gives in pure nitric acid, as also in pure muriatic acid, 

 a weak and transient, according to De la Rive's statement, an 

 imperceptible current, but in aqua regia an apparently strong 

 one. Many similar examples are mentioned which all belong 

 to the same class. However, supposing that the mixture of 

 the fluids does not change their conducting power *, it is still 

 questionable whether the increased effect in all these cases 

 produced by increased chemical action does not depend merely 

 on this, that the opposition to the transfer decreases with die 

 increase of chemical action. In fact I have shown in my gal- 

 vanic measurements that this opposition is smaller in power- 



[* It appears to us, on the contrary, that the chemical action which 

 ensues on the mixture of the nitric and muriatic acids, hy which they are 

 both, in part, decomposed, must effect a corresponding change in their 

 conducting power. — Edit.] 



