Professor Grove on a Gaseous Voltaic Battery. 419 



in one direction throughout the circuit, and the oxygen in the 

 reverse. It was found that 26 pairs were the smallest num- 

 ber which would decompose water, but that four pairs would 

 decompose iodide of potassium. 



5th. A gold leaf electroscope was notably affected. 

 6th. The battery was charged with distilled water; the elec- 

 troscope was affected, and iodide of potassium decomposed. 



7th. Although the phenomena were too marked to render 

 it in the least probable that accidental circumstances could 

 have produced the current, still counter experiments were care- 

 fully gone through ; thus the gases were repeatedly changed, 

 oxygen being placed in the tubes which had contained hydro- 

 gen, and vice versa. The effects were equally powerful, and 

 the direction of the current was reversed. 



8th. All the tubes were charged with atmospheric air; no 

 effect was produced. 



9th. The battery was charged with carbonic acid and nitro- 

 gen in the alternate tubes ; not the slightest effect observable. 



10th. It was charged with oxygen and nitrogen; not any 

 effect. 



11th. With hydrogen and nitrogen, slight effects. The 

 difference between this and the last experiment at first struck 

 me as extraoi'dinary, but upon consideration was easily ex- 

 plicable. The liquid being exposed to the air would neces- 

 sarily absorb some oxygen, and this with hydrogen would give 

 rise to a current. This was proved by the liquid rising in the 

 hydrogen tubes, but not in those containing nitrogen ; and, 

 as a further proof, one set of tubes was charged with hydro- 

 gen, and the alternate set with acidulated water without gas ; 

 a slight current was perceptible : with oxygen and the liquid 

 in alternate tubes there were no effects produced. 



12th. As the oxygen and hydrogen were procured in the 

 first instance by electrolysis, and as Dr. Schcenbein in his 

 careful experiments on polarized electrodes supposed the pe- 

 culiar substance which he has named Ozone to be a principal 

 agent, I caused the tubes to be charged with oxygen evolved 

 from chlorate of potash and oxide of manganese, and hydro- 

 gen from zinc and sulphuric acid ; the effects were the same. 



The tubes were not all of equal size, nor were they gra- 

 duated ; the exact proportional diminution of gas in each tube 

 could not be ascertained with perfect accuracy ; both gases did 

 diminish, and the hydrogen so much more rapidly than the oxy- 

 gen, that my assistant, who was unacquainted with the rationale 

 of the battery, observed that the hydrogen was absorbed twice 

 as fast as the oxygen. Mr. Gassiot is now preparing a gra- 

 duated battery of this sort, by which the point will be accurately 



2F2 



