548 M. PoggendorfF on Galvanic Circuits composed of 
bottom of a cylinder which contained the platina and nitric 
acid^ and was surrounded by a wider one which received the 
zinc and sulphuric acid. 
To be perfectly certain that the mixed acids did not develope 
greater electromotive force than the separated, I caused them 
to oppose one another by substituting in the apparatus just 
described an acid mixture for the iodide of potassium. The 
experiment was in other respects similar to the previous one, 
only that the acids had a somewhat different degree of concen- 
tration. Both diluted acids consisted of 1 part by weight of 
concentrated acid, and 3 parts by weight of water, and equal 
parts by weight of them were mixed on the one side of the 
circuit with each other, and separated on the other side by 
bladder. The experiment was made both with amalgamated 
and non-amalgamated zinc, and previously heated platina. 
In both cases the result was, that the separated acids not only 
excite an etectromotive force quite as great as- the mixed, but 
have indeed a slight superiority over these ! The latter fact is 
the more remarkable, as the zinc plate (even amalgamated), im- 
mersed in the sulphuric acid containing nitric acid, is evidently 
more strongly attacked than that in the pure acid, and yet, after 
washing both in water, is in this fluid negative towards the 
latter plate. 
I consider these facts, indeed, as more demonstrative than 
those already mentioned at p. 541, with the hydrochloric acid ; 
nay, as so decisive, that I regard the proofs against the tenabi- 
lity of the argument, derived from Faraday^s experiment, in fa- 
vour of the chemical theory of galvanism, as perfectly destroyed 
by them*. 
However I cannot refrain from drawing attention to the cir- 
I 
* The above fact is certainly decisive against the Faradayan theory, which 
merely admits the chemical attack on metals as the cause of the voltaic electricity. 
On the other hand, according to the theory of Becquerel or De la Rive, one 
might deduce this near equality in the action of the separated and mixed acid 
from an accidental compensation with the current originating from the contact 
of both acids. Now fluids excite, it is true, an electric current by their reci- 
procal contact, as was first actually proved by Fechner (Poggendortf’s Annalen, 
xlviii. pp. 1, and 225.). A portion of the action may therefore in effect have 
originated from this cause ; but since the currents, which truly originate from 
the reciprocal contact of the fluids, are always weak only, it is not probable 
that this portion was considerable, and exercised any great influence on the 
main result. As already mentioned, the separated acids have the superiority 
over the mixed when the platina is inserted in the nitric acid ; the reverse 
happens when the %inc is immersed in the nitric acid. But in both cases the 
superiority is only slight. This appears to me to prove, that the current from 
the fluids which in both cases must possess opposite direction, has no consider- 
able part in the main action. 
