42 Journal of the Asiatic Society of Bengal. [February, 1910. 



bubbling of gases though still noticeable, was considerably re- 

 duced, especially that from the cathode. 



The acid character of the impure stuff, as guessed by the 



rystals it had yielded 



was 



evolved at the time of electrolysis. Both the solutions were, at 

 this stage, tested for acid. The impure stuff was found to be 

 strongly acid on chemical examination, the pure stuff only gave 

 a slight acid reaction. 



In order to examine whether the acid character of the 

 solutions was the cause of the effervescence at the time of 

 electrolysis and of the low values of the e.c.e., both the 

 solutions were treated with precipitated Nickel Carbonate and 



filtered . 



Experiments were now repeated with these neutralized 

 solutions with a view to see if the absence of acid would also 



marked 



of 



gaseous evolutions at the electrodes, as well as by a larger 

 amount of deposit on the cathode, giving thereby a higher value 

 of the e.c.e. 



Results. 



The evolution of gases was found to be considerably reduced 

 in the impure solution at the first electrolysis after treatment 

 with Nickel Carbonate. Only very minute bubbles appeared 

 at the cathode; at the anode the evolution of gas was still 

 fairly large though much reduced. In the pure solution no 

 difference was perceptible. 



The impure stuff gave a value more than double its value 

 before neutralization, better even than the one given by the 

 pure stuff. The value, however, fell steadliy on repeated 

 electrolysis, being successively 



Before treatment :— -000127 



•0002770— 1st electrolysis. 

 After treatment :— \ 0002406— 2nd electrolysis. 



•0001666— 3rd electrolysis. 



The pure stuff did not show any improvement at all. On 

 the contrary the values were not quite so good as before, and 

 the fall in successive experiments was even more marked and 

 accompanied by a distinctly brisker evolution of gases. 



Before treatment : — 0002590 



After treatment :— X 999?? 5 ? — lst electrolysis. 



0001507— 2nd electrolysis. 



The condition as regards time, current and temperature 

 were almost the same throughout this series, yet the variations 

 in the value of the e.c.e. are extremelvlar^e. 



