356 Prof. A. Schuster and Mr. A. W. Oossley. [Jan. 21, 



In the last three experiments, which gave comparatively large 

 differences, the solutions used were kept separate between the expe- 

 riments, and this leads us to think that we had previously committed 

 an error in mixing our solutions, which, as has already been stated, 

 must gradually have become free of air. Experiment 29 shows, how- 

 ever, too great a difference ; some of the silver in the bowl kept in air 

 may have been lost in the washing. 



It seems remarkable that the electro- chemical equivalent of silver 

 as deduced from the electrolysis in vacuo is almost identical with that 

 obtained in Lord Eayleigh and Mrs. Sidgwick's deposits from hot 

 solutions. 



One point as yet remains to be discussed. It was reasonable to 

 assume that the increased deposit in vacuo was due to the removal of 

 the oxygen out of the solution. In order to obtain more definite 

 information, we took some deposits in an atmosphere of oxygen. In 

 the first experiment the two bell-jars were exhausted, and one of 

 them filled' with oxygen, which was allowed to stand for three hours 

 over the solution before electrolysis. 



The result was as follows : 



Deposit in air (small bowl) 1 '8618 



oxygen 1 "8618 



(large bowl) I '8624 



There is here no difference except that due to the size of the bowl. 

 As it seemed doubtful whether the oxygen had in the course of three 

 hours been absorbed to its full extent by the solution, three more 

 experiments were made and conducted as follows 



One small basin was kept in air as before ; the other was kept 

 in vacuo, while the large basin was filled with a solution which after 

 boiling had a stream of oxygen passed through until it was con- 

 sidered that the liquid was saturated with the gas. The solution 

 thus prepared was kept in an atmosphere of oxygen. The com- 

 parison between the deposits in air and vacuo have already been 

 given (Experiments 29, 30, 31, Table VII). 



The weight of the deposits in air and in oxygen was as follows : 



Small bowl Large bowl Percentage 



in air. in oxygen. difference. 



1-8495 1-8488 0*04 



1 -8990 1 -8983 "04 



1 '8989 1 -8981 '04 



We attribute the consistency of these results partly, at any rate, to 

 the fact that the solutions used in the three bowls were kept 

 separate 



