GAS BATTERY, 271 



with more caution, in a state passing from gaseous to liquid, 

 I tried 



Experiment 15. One set of tubes charged with gaseous 

 chlorine, and the alternate tubes with solutions of bromine 

 and iodine. The chlorine was negative to both, i.e. was to 

 these as oxygen to hydrogen. 



I now tried hydrogen with several gases ; but as it was 

 next to impossible (I found 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.-)- I shall, therefore, not go through these experi- 

 ments 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 power- 

 ful 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 reasons above stated (Experiment 13). 



Chlorine, in its voltaic relations, may be considered as the 

 converse of zinc, both decomposing water, but the one libe- 

 rating 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 diaphragm battery with per- 

 oxide of manganese and muriatic acid, but the supply of 

 chlorine thus obtained is insufficient for quantitative voltaic 

 effects, though the intensity is great. 



Experiment 17. Hydrogen and carbonic oxide were tried 



* 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, Phil. Mag., March 1843. 



