166 | Onthe Theory of the Gaseous Voltaic Battery. 
combined with chemically pure water, and the circuit thus 
formed completed by platinum, produces a current which 
passes from the solution to the water, though no trace of free 
oxygen should happen to be contained in either fluid. By 
letting pass eitlier the latter gas or atmospheric air into the 
solution of hydrogen, I could not sensibly increase the cur- 
rent produced by the arrangement, from which negative re- 
sult I thought I was entitled to draw the conclusion, that the 
current being generated under those circumstances cannot be 
due to the combination of free hydrogen with isolated oxygen; 
an inference which may also be drawn from Mr. Grove’s ar- 
rangement itself, for the oxygen being contained in one tube 
cannot be supposed to combine with the hydrogen inclosed 
in another tube. 
An aqueous solution of oxygen being voltaically associated 
with pure water is not capable of exciting a sensible current 
if the circuit happens to be completed by means of platinum, 
a fact from which it seems likewise to follow that in Grove’s 
novel pile oxygen does not immediately contribute to the pro- 
duction of its current. 
But if the current of that arrangement be, nevertheless, 
augmented by having the alternate glass-tubes filled with 
oxygen, I am inclined to ascribe that effect to the depo- 
larizing action exerted by oxygen upon the negative platinum 
‘ electrodes which are inserted in the tubes containing that 
gaseous body. From obvious reasons that action must be 
greatly facilitated and accelerated by the well-known power 
of platinum to favour the chemical union of hydrogen with 
oxygen. 
It is, however, very likely that in the oxygen tubes, besides 
the depolarizing action, there is some other electromotive 
force called into play; but having treated of this subject in a 
paper (‘¢ On the electrolytical power of a simple pile”) which, 
I presume, was read before the British Association at Man- 
chester, and published in the last Number of De la Rive’s 
Archives, I will not enter into more details on that subject, 
but take the liberty of referring to the memoir itself. 
I remain, my dear Sir, 
Yours very truly, 
Basle, Dec. 28, 1842. ' C. F. Scua@nsein. 
P.S. Experimenters who are desirous of pursuing Mr. 
Grove’s late researches, will find the effects of the gaseous 
pile greatly enhanced by making use of chlorine gas instead 
of oxygen; at least the experiments I made on the voltaic 
properties of chlorine and bromine, some time ago, lead to 
such a conclusion. 
