GAS BATTERY. 277 



interchange is, however, removed when the gases are in a state 

 of such intimate admixture that it is not requisite to convey 

 the action through a chain of particles ; in the gas battery 

 this chain is supplied by the intervening electrolyte, and thus 

 the same action which is local in the experiments of Dobereiner 

 is circulating in the gas battery. The latter bears the same 

 relation to the former as the action of the ordinary voltaic 

 battery does to the normal phenomena of chemical affinity. 

 This relation is confirmed by the facts detailed in the paper 

 of Dr. Henry, as the gases which he there found would com- 

 bine by the presence of spongy platinum are precisely those 

 which will combine in the gas battery ; thus oxygen and 

 hydrogen combine rapidly, oxygen and carbonic oxide much 

 more slowly, and oxygen and olefiant gas very feebly, so much 

 so, as, in Henry's experiments, to require heat to induce com- 

 bination. Of course chlorine and hydrogen, which will unite 

 without platinum, will, a fortiori, unite with the aid of plati- 

 num, or they may in the gas battery occasion secondary 

 action ; the oxygen evolved by the decomposition of water by 

 the chlorine combining with the free hydrogen in the tube. 

 As oxygen and ammonia will, when at a slightly elevated 

 temperature, combine by the influence of spongy platinum, 

 forming water and leaving nitrogen, I now, in order farther to 

 test this relation, tried 



Experiment 26. Ten cells of the gas battery were charged 

 with oxygen and solution of ammonia, with a little sulphate 

 of ammonia added to improve its conducting power. This 

 arrangement produced a moderate effect upon the iodide, which 

 was continuous ; the liquid rose slowly but uniformly in the 

 oxygen tubes ; a gas was evolved in the alternate tubes, 

 which proved to be pure nitrogen. After three weeks closed 

 circuit, the gases, collected, measured, and averaged, gave for 

 each tube 



Nitrogen evolved . . . . = 0*07 cubic inch. 

 Oxygen absorbed . . . = O' 1 2 cubic inch. 



Experiment 27. To examine whether the mere alkaline 

 character of ammonia had anything to do with the effect, ten 

 cells were charged with oxygen and solution of caustic potash, 

 but produced no effect 



