268 EXPERIMENTAL INVESTIGATIONS. 



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 

 phenomena. When not otherwise mentioned, the electrolyte 

 will be considered as dilute sulphuric acid, sp. gr. r2. 



. Experiment 8. A battery charged with oxygen and pro- 

 toxide 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 

 examining 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 O'2 cubic inch ; in the detached pair it 

 had risen to the same amount. Not the slightest voltaic effect 

 was now produced by the terminal wires. 



Experiment 10. Oxygen and olefiant gas decomposed the 

 iodide, but rather feebly ; 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 detached pair, in tubes of 

 Oxygen . . . 0*02 cubic inch. 

 Olefiant gas . . O'3 



Rise of liquid apparently due to voltaic action, 

 In oxygen tubes . 0^03 cubic inch. 

 In olefiant gas tubes . O'l 



