312 Mr Shaw, On experiments with mercury electrodes. [Dec. 8, 



mean position by means of magnets. The effects due to the 

 raising and sinking of the piston diminished with the increasing 

 E. M. F. until with an E. m. F. of "2 Daniell they were no longer 

 appreciable. But raising the whole funnel T produced small 

 throws of the galvanometer until the E. M. F. was "35 Daniell, 

 when the only remaining effects were slight changes in the per- 

 manent current. 



It would thus appear that the result described by Varley was 

 obtained in this case for an e.M.f. of about "35 Daniell cell. 



Proceeding to confirm this result I repeated the experiments 

 with fresh mercury and fluid, and without first depositing hydrogen 

 on the movable mercury electrode. The result of the observations 

 will be seen from the following table : 



At this point some of the fluid was taken out and found on 

 testing with H^S to contain mercury. The disturbance in the 

 fluid produced a large effect upon the current flowing through it, 

 and it was accordingly allowed to remain over night in order to 

 regain its previous state. On the following day observation gave 

 for E.M.F. -1 Daniell a throw of +2" in pushing down, but none 

 on raising the piston. After this the whole funnel T was raised 

 and lowered, the observations gave — 



On the following morning the current having passed all night 

 •21 I +15" I 



