GAS BATTERY. 273 



the theory of the gas battery would indicate. Thus, in the 

 present experiment, the appearance of iodine indicated oxygen 

 to have the same voltaic relation to nitrogen as it has to 

 hydrogen. This temporary effect, therefore, appears to me 

 analogous to that action called by Continental experimentalists 

 polarisation, an apparent tendency to action, i.e. an arrange- 

 ment of molecules preliminary to electrolysis, but incapable 

 of producing a continuous current. In this and many other 

 experiments with the gas battery I have observed this effect, 

 but have never been able to produce any chemical change or 

 electro-synthetic absorption of nitrogen. 



Experiment 22. As oxalic acid when electrolysed evolves 

 at the anode a mixture of oxygen and carbonic acid, and at 

 the cathode hydrogen and carbonic oxide, for the reasons 

 above stated I charged a gas battery with carbonic acid and 

 carbonic oxide in the alternate tubes, and with oxalic acid as 

 an electrolyte ; a slight effect was produced, the carbonic 

 oxide being to the carbonic acid as hydrogen to oxygen ; but 

 the current was evidently due to the atmospheric air in solution 

 combining with the carbonic oxide ; this I proved by some 

 of the test experiments before-mentioned, which I need not 

 recapitulate. 



Experiment 23. Hydrogen, nitrogen, and sulphate of am- 

 monia. This combination also gave effects with which the 

 nitrogen appeared to have nothing to do, this gas being per- 

 fectly unaffected. I tried other experiments on this point, but 

 they all led to the same conclusion, viz. that my idea of real- 

 ising a voltaic action by conversion of the ordinary effects 

 of electrolysis was erroneous. It may be that the above 

 gaseous products of electrolysis are secondary, and that water 

 is the only electrolyte in these cases ; but for this, as for many 

 other theoretical questions, there are so many arguments pro 

 and con, that it is not worth while to dilate on them unless 

 they can be shown to lead, or to be likely to lead, to some 

 new valuable facts or natural relations. 



Reviewing the above experiments, it appears that chlorine 

 and oxygen, on the one hand, and hydrogen and carbonic 

 oxide, on the other, are the only gases which were decidedly 

 capable of electro-synthetically combining so as to produce a 



T 



