34 Mr.Grove on the Subject of Mr.Daniell’s last Communication. 
on this point, it is too frivolous. New batteries, or new phi- 
losophical experiments of any sort may differ in every parti- 
cular from old ones and yet be valueless, while on the other 
hand a very slight alteration may constitute an important dis- 
covery. Mr. Daniell’s battery varied only in one element from 
those previously known. 
I have already published my opinions on the principles of 
the voltaic battery and need not repeat them, but as it is ne- 
cessary to be explicit, I will refer to one other point wherein I 
differed, and stil! differ, from Professor Daniell. In the above- 
mentioned lecture at the London Institution I drew a broad 
line (not an imaginary line, but a broad line with chalk on 
a black board) between metallic solutions and highly oxy- 
genated acids, such as the nitric, chloric, &c.; I still hold to 
this distinction. Now Professor Daniell, in his long paper re~ 
cently published containing many experiments on my battery, 
interspersed with simple equations, arrives in the last page at 
the following conclusion :—* If chloride of platinum were not 
too expensive to allow ofits being employed as the exterior 
part of the electrolyte in contact with a platinum conducting 
plate, e', or the contrary electromotive force would be wholly 
annihilated, as nothing but platinum would be thrown down 
upon the platinum, and it would constitute the most perfect 
possible arrangement, but would not much, if anything, exceed 
the efficiency of nitric acid.”—Phil. Trans., 1842, p. 287. 
This is no verbal statement, but a paper, I presume, delibe- 
rately prepared, communicated to the Royal Society, and pub- 
lished in its Transactions. Now I deliberately assert that the 
above arrangement is not the most perfect possible, nor nearly 
so; that it is very inferior to the nitric acid; that the princi- 
ples of the voltaic battery, as I conceive them, led me to this 
conclusion, and that experiment confirmed it. I find, more- 
over, that I am not solitary in this opinion. I am glad that 
Mr. Daniell and myself here differ, not merely upon princi- 
ples or their application, but upon facts, of the correctness of 
which any experimentalist can satisfy himself. I will venture 
to suggest to any one who may like to try the experiment, 
that care should be taken not to have any nitric acid mixed 
with the chloride of platinum, as if so, from its great supe- 
riority as an electrolyte (having five equivalents of an electro- 
negative element), the nitric acid will be deoxidated and the 
platinum vot thrown down *. 
* Note, Dec. 19.—My attention has just been called to a report of my 
lecture, Phil. Mag. 8. 3, vol. xviii. p. 234. This confirms what I have said 
above, and proves that the lecture was simply an historical review of the 
voltaic piles used in practice and an explanation of them all on the chemical 
theory. 
