344 KOLLOCK AND SMITH— RESULTS IN ELECTROLYSIS. [October 4 



ferricyanide would form three molecules of ferrocyanide with the 

 splitting off of one radical, thus : 



4K3Fe(CN)e = K,3Fe,(CN)34 

 3K,Fe(CN)e = K,,Fe3(CN),3 



Fe(CN)e 

 This would therefore give 



4K3Fe(CN)6 : Fe(CN)6 • * 0-1323 gram : 0.0213 gram. 



By constant and careful observation of the voltmeter, it was 

 thought the end of this reaction could be detected. 



In the first experiment with this end in view, a current of 0.4 

 volt and o.ooi ampere was passed through the solution of potassium 

 ferricyanide. There was a constant tendency of the voltage to rise. 

 But by throwing in resistance this was maintained at 0.4 volt, the 

 current falling to 0.0002 ampere. In about thirty minutes the volt- 

 age was observed to fall slightly. The current was then interrupted. 

 The anode had increased 0.0217 gram and there was no potassium 

 hydroxide detected in either cell. Subsequent experiments, carry- 

 ing out the same plan, gave 0.021 1, 0.0214, 0.0209, 0.0213 gram 

 increase in weight of the anode. The operations required constant 

 and careful attention, inasmuch as the point at which the change 

 takes place is momentary. The speed of the anode in all cases was 

 about seventy-four revolutions per minute. The time required for 

 the reaction varies slightly with the conditions, as may be observed 

 from the following table : 



