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



this work later and to seek for an explanation of its discrepancy, 

 and in the meantime to ascertain the effects of lower currents upon 

 both potassium ferrocyanide and potassium ferricyanide. 



A thermopile was used as the source of the current in all the 

 subsequent work. A water rheostat was constructed from a battery 

 jar about twelve inches high by 9" by 6" cross section, containing 

 a dilute solution of sodium chloride in which were immersed two 

 lead plates six inches square. The resistance was regulated by 

 raising or lowering the plates in the solution. The voltmeter, 

 graduated to one thirtieth of a volt, and the milliammeter were con- 

 tinually in the circuit. 



Potassium ferrocyanide was acted upon by a current of 0.4 volt. 

 This gave a current unappreciable on the milliammeter. It acted 

 for an hour and a quarter. There was no decomposition observed 

 in the outer cell. Titration of the contents of the inner cell with 

 N/io hydrochloric acid showed the presence of 0.0039 gram of 

 potassium. The anode increased in weight by 0.0052 gram. This 

 is in about equivalent quantities. (The theoretical equivalent of 

 potassium would be 0.00382 gram.) By using a current of 0.13- 

 0.16 volt, there was no evidence of decomposition, either in increase 

 in the weight of the anode or evidence of potassium hydroxide in 

 either cell, with phenolphthalein as indicator. Even 0.02 volt in 

 one hour had not effected any change, but with 0.23 volt, the anode, 

 after an hour's action of the current, had increased 0.0004 gram, 

 and a faint pink color was observed when phenolphthalein was 

 added to the solution in the inner cell. This was dispelled by a 

 fraction of a drop of N/io hydrochloric acid. With a current of 

 0.266 volt, the anode after the same period of time had increased 

 0.0014 gram. When 0.3 volt was employed 0.0022 gram of 

 Fe(CN)6 had separated on the anode and 0.00039 gram of potassium 

 was found in the solution. A current of 0.4 volt showed 0.005 

 gram of Fe(CN)6 and 0.00107 gram of potassium, while 0.5 volt 

 gave 0.0064 Fe(CN)6 and 0.0041 gram of potassium. 



The following table shows the effect of increase in the current: 



