Mr. Grove on the Gas Voltaic Battery. 349 



detached and unconnected pair, the effects due to solution, 

 local currents, or other causes could be abstracted from those 

 due to circulating voltaic action. 



I shall arrange the following experiments in the order in 

 which I instituted them, making such comments as may be 

 necessary to explain my own deductions from the resulting 

 phaenomena. When not otherwise mentioned, the electrolyte 

 will be considered as dilute sulphuric acid, sp. gr. 1*2. 



Experiment 8. — A battery charged with oxygen and prot- 

 oxide of nitrogen produced no effect upon iodide of potassium. 

 Examined next day the liquid had not risen in the oxygen 

 tubes ; in the protoxide tubes it had risen to an average of 0*3 

 cubic inch, both in the battery and detached pair. 



Experiment 9. — Oxygen and deutoxide of nitrogen pro- 

 duced a slight effect upon the iodide; the effect subsided after 

 the circuit had been complete for a few minutes. On exami- 

 ning the battery after the circuit had been closed for twenty- 

 four hours, the liquid in the oxygen tubes had not risen ; in 

 the tubes containing deutoxide of nitrogen, the liquid had 

 risen somewhat unequally in the different tubes to an amount 

 averaging 0*2 cubic inch; in the detached pair it had risen to 

 the same amount ; not the slightest voltaic effect was now pro- 

 duced by the terminal wires. 



Experiment 10. — Oxygen and olefiant gas decomposed the 

 iodide, but rather feebly j after the circuit had been closed for 

 twenty-four hours there was still a decomposition, which con- 

 tinued, but the action was extremely feeble. Two cells were 

 allowed to remain arranged in closed circuit for fifteen days, 

 a third being placed by the side, but with the terminals un- 

 connected ; at the expiration of this time the rise of liquid in 

 the tubes was as follows : — 



Rise of liquid in cells of closed 



circuit, in tubes of 

 Oxygen . 0*05 cubic inch. 

 Olefiant gas 0*4 



Rise of liquid in cells of de- 

 tached pair, in tubes of 

 Oxygen . # 02 cubic inch. 

 Olefiant gas 0*3 



Rise of liquid apparently due to voltaic action, 

 In oxygen tubes . . . 0*03 cubic inch. 

 In olefiant gas tubes . 0*1 •«« 



These quantities are too small to enable any satisfactory in- 

 ference to be deduced as to the equivalents of these gases which 

 contributed to electrolysis; the more so as the rise of liquid 

 was not quite uniform, and the action due to solution was so 

 much greater than that due to electrolysis. 



I do not feel entitled to draw any other conclusion from 

 this experiment than that there was a very feeble voltaic cur- 



