Mr. Grove on the Gas Voltaic Battery. 273 



manner to fig. 1. By immersing this apparatus in the water- 

 trough, each tube with the gas it contains may be detached and 

 examined separately, but its principal advantage is, that by 

 slightly greasing the stopper and collars it may be made per- 

 fectly air-tight, which, for reasons that will be apparent in the 

 course of this paper, is a most material point. This appa- 

 ratus, moreover, being entirely composed of glass and plati- 

 num, concentrated acid, alkaline or other corrosive solutions, 

 may be used as the electrolyte, without damaging the appa- 

 ratus or introducing foreign matter. 



In the experiments I am about to describe, the results were 

 generally tested by chemical action, as manifested by the elec- 

 trolysis, either of iodide of potassium or of water. I had at 

 my disposal a highly sensitive astatic galvanometer, but I found 

 such slight local actions disturb it, that a range of test expe- 

 riments was in each case necessary to eliminate the true bat- 

 tery action from the accidental currents; and with all the 

 pains that could be bestowed upon it, the results were less 

 definite and trustworthy than those obtained with the iodide. 



I may here state also, that, although with the battery de- 

 scribed in my original paper when charged with oxygen, hy- 

 drogen and dilute sulphuric acid, I could not succeed in per- 

 ceptibly decomposing water with less than twenty-six cells, 

 yet the new arrangements, from their superiority in size and 

 construction, were capable, when charged with the same gases 

 and electrolyte, of decomposing water with four cells ; and a 

 single cell would decompose iodide of potassium. 



Experiment 1. — Ten cells charged to a given mark on the 

 tube with dilute sulphuric acid, sp.gr. 1*9, oxygen and hy- 

 drogen, were arranged in circuit with an interposed voltame- 

 ter*, as in figs. 6 and 7, and allowed to remain so for thirty- 

 six hours. At the end of that time 2*1 cubic inches of mixed 

 gas were evolved in the voltameter ; the liquid had risen in 

 each of the hydrogen tubes of the battery to the extent of 1*5 

 cubic inch, and in the oxygen tubes 0*7 cubic inch, equalling 

 altogether 22 cubic inches; there was therefore O'l cubic 

 inch more of hydrogen absorbed in the battery tubes than was 

 evolved in the voltameter. 



* These experiments were made with the battery fig. 1, though for more 

 clearly showing the volumes of the gases the second form is represented in 

 figures 6 and 7. The voltameter employed on this occasion had electrodes 

 of fine piatinum wire a quarter of an inch long. From the nature of the 

 gas battery it is difficult to know the efficient surface of the plates. In or- 

 dinary batteries I have found, and stated some time ago, that for quanti- 

 tative effects, the electrodes should be of the same size as the battery 

 plates. 



Phil. Mag. S. 3. Vol. 24. No. 159. April 1844. T 



