486 M. PoggendorfF on Galvanic Circuits composed of 
It can no longer, therefore, be a question whether there is a 
true spark on junction without metallic contact ; moreover, 
other good reasons render very improbable the existence of the 
high tension requisite in the still open simple circuit*. 
The electrolytic law is otherwise circumstanced. The cor- 
rectness of this important law, with w^hich Faraday has en- 
riched the science of electricity, can be subject to no doubt ; 
but many w^ell-founded objections maybe raised against its inter- 
pretation in favour of the chemical theory. The law consists 
in the fact that the quantities of the bodies decomposed in the 
single cells of the voltaic battery are in proportion to the che- 
mical equivalents. It proves that the passage of like quantities 
of electricity is necessary for the decomposition of equivalent 
masses, but nothing more. It takes no part in the question 
respecting the origin of galvanic electricity. It is equally 
correct, whether the voltaic current originate from the contact 
of the metals, or from the chemical action on the zinc, or from 
any other cause f. 
A proof in favour of the one or the other origin might 
perhaps be drawn from it, were it exclusively peculiar to the 
voltaic current, which would at the same time establish quite 
an essential distinction betw^een voltaic electricity and magnetic, 
thermal, frictional, and animal electricity. But if, on the other 
hand, it is no peculiarity of the voltaic electricity, if it is rather 
* [At the time when the sheets of the German original were sent to press, Prof. 
Poggendorffhad not seen the collective edition of the Experimental Researches, 
in the preface to which Mr. Faraday acknowledges himself to have been in 
error with respect to the production of the spark without contact. — W. F.] 
t The error with respect to using this law as an argument has originated 
from presupposing what first ought to have been proved by it, that the excita- 
tion of the electricity was effected by the solution of the zinc ; while in reality, 
this solution, when amalgamated zinc and dilute sulphuric acid are employed, 
is solely the effect, the product of the electric current, and, when common zinc 
is used, arises partly from this current and in part from a pure chemical process 
entirely foreign to the circuit. It has happened with this law as with the well- 
known fact that in general the easily oxidable metals are the more positive. 
A connexion between oxidability and positiveness is accordingly evident, but 
which of these is causal, this or that, remains totally undecided. That it is, 
nevertheless, still continued to be interpreted in favour of the chemical theory, is 
the less justifiable, as several cases are known (and may every moment be 
increased by new ones) where the negative metal, notwithstanding that it is 
actually much more powerfully acted upon by acids than the positive one, still 
remains negative towards this. We need only call to mind the old experiment 
of Berzelius {Gilb. Annalen, vol. xxxv. p. 27), which, it is true, De la Rive 
conceives he has refuted, but which has long since been satisfactorily confirmed 
by Ohm. Moreover, the fact observed by Ritter, Davy, and many others, and 
which I have recently confirmed, that amalgamated zinc, notwithstanding it is 
little or not at all attacked by dilute acids, is in these considerably positive 
towards the so easily soluble unamalgamated zinc, deserves to be rescued from 
oblivion. 
