166 Prof. Schoenbein's Discussion ofM. Fechner's 



place, we must infer that both currents in question are ge- 

 nerally equal to one another. The equality of the currents 

 resulting from our two systems of cells is, no doubt, in some 

 way or other connected with the fact, that two piles containing 

 the same number of equal pairs, but being charged with dif- 

 ferent exciting fluids, exhibit in general no difference of ten- 

 sion at their insulated poles. As De la Rive has already dis- 

 cussed that point in his memoir entitled " Recherches stir la 

 Cause de I'Electrzciie volta'ique,^^ I do not think it necessary 

 to enlarge upon it any further. 



It appears to me that the preceding remarks are sufficient to 

 demonstrate that the current equilibrium which results from 

 the peculiar arrangement which has been mentioned of two 

 compound circles (only differing from each other with regard 

 to their respective exciting fluids) is by no means contradictory 

 to the principles of the chemical theory, no more than, for 

 instance, the fact is, that a pile consisting of ten voltaic pairs, 

 half of them put into water cells, the other half into acid 

 ones, and arranged in the usual way, produces a current much 

 weaker than that which is obtained from five pairs alone 

 placed within the acid fluid. For the same reasons which 

 make Fechner consider the equilibrium in the first case as an 

 evidence against the correctness of the chemical theory, he 

 must draw similar conclusions from the results of the second 

 case; for he may ask, why should the voltaic effect of ten 

 pairs be smaller than that produced by only five pairs ? as 

 there can be no doubt that the extent of the chemical action 

 of the whole arrangement is greater than that of only a part 

 of it. After what has already been said about the subject, it 

 would be quite superfluous to answer such a question. 



As to the differences of currents mentioned in the beginning 

 of this paper, those differences being sometimes in favour of 

 the water system, sometimes of that of the acid system, I am 

 inclined to think them connected with certain changes which 

 the pairs functioning in the pile undergo with regard to their 

 conducting powei , though I am not able as yet to assign the 

 ultimate cause of the modifications in question. There can, 

 however, hardly be entertained a doubt about the occurrence 

 of such changes ; and to prove the correctness of the assertion, 

 I have only to mention iron, which being in its peculiar con- 

 dition, proves to be a very bad current-conductor, compared 

 to what it is in this respect when in its ordinary state. 



Dr. Faraday, in his comments upon my first letter addressed 

 to him, (L. & E. Phil. Mag., vol. ix. p. 60.) says that the voltaic 

 relation of inactive iron to platina afforded a decisive proof, 

 that contact of itself, independent of chemical action, is inca- 



