MR. GROVE ON THE GAS VOLTAIC BATTERY. 
103 
it quite impossible), in experiments on a large scale, perfectly to exclude atmospheric 
air from the solution* * * § , voltaic action was produced in every case; and as with one 
exception (chlorine) oxygen was the most powerful electro-negative gas, the action 
of the atmospheric air entirely masked any effect which might have been produced 
by the other gases -f'. I shall, therefore, not go through these experiments in detail, 
but mention one or two only which appear interesting, for the reasons which I shall 
state. 
Experiment 16. — Chlorine and hydrogen gave very powerful effects, as was expected 
by Dr. Schcenbein^; water was decomposed between platinum electrodes by two 
cells. This is the most powerful gas battery §, but not very satisfactory, for the rea- 
sons above stated, experiment 13. 
Experiment 17. — Hydrogen and carbonic oxide were tried in order to ascertain 
their voltaic relations. Hydrogen was much more electro-positive than carbonic 
oxide, or rather formed, with the oxygen of the atmospheric air in solution, a combi- 
nation which overpowered the opposite tendency of the carbonic oxide and air. 
Experiment 18. — Chlorine and olefiant gas gave a very feeble effect upon iodide of 
potassium. After four hours the liquid in the olefiant gas tubes had not risen more 
in the closed circuit than in the detached pair ; the chlorine was nearly all absorbed 
in solution. 
Experiment 19. — Chlorine and carbonic oxide gave very notable effects ; ten cells 
decomposed water. From the extreme solubility of the former gas, the equivalent 
relationship could not be ascertained. 
It now occurred to me that as oxygen and hydrogen are evolved from water by 
electrolysis, and conversely form water by electro-synthesis, so some other gases 
which are evolved from certain electrolytes by voltaic action, might, when arranged 
as a gas battery with the electrolyte from which they are evolved, give rise to a cur- 
rent, although they would not do so when arranged in circuit with a different elec- 
trolyte. To test this view I tried, 
Experiment 20, — Oxygen and deutoxide of nitrogen in alternate tubes of the gas 
battery, with dilute nitric acid ; the effects were however precisely similar to experi- 
* Gases will creep by a species of endosmose through water. Some time ago I kept inverted over water 
for two months, a vessel divided by a diaphragm of porous ware, on one side of which was oxygen gas, on the 
other hydrogen ; the diaphragm was constantly wet from capillary attraction ; at the end of that period the 
water had risen considerably, and the gases on each side detonated. 
f See Postscript. 
+ See his letter, Philosophical Magazine, March 1843. 
§ Chlorine, in its voltaic relations, may be considered as the converse of zinc, both decomposing water, but 
the one liberating oxygen, the other hydrogen ; thus a tube of the gas battery charged with chlorine, and 
having acidulated water as an electrolyte, and zinc as a positive element, forms a combination of which one 
pair will decompose water. I have tried to render this combination practically useful, by charging the negative 
cell of a nitric acid battery with peroxide of manganese and muriatic acid, but the supply of chlorine thus ob- 
tained is insufficient for quantitative voltaic effects, though the intensity is great. 
