

J. II. Pratt — Capit 



'lary i 



Electr 



ometer. 



1 







Table II.— March 22, 



1887. 







E. M.F. 



Deflect. 



E. M. F. 



Deflect. 





E. M.F. 



Deflect. 



•01 Dan. 







•40 Dan. 









1-41 Dan. 



1 -o mm 



•02 



•Jmm 



•60 



• "[mm 





1-42 



2-0 mm 



•04 







•80 









1-50 



3.0mm 



•08 







•90 









1-60 



n -Qmrn 



•10 



•2 



1-00 









1-80 



13-0 mm 



•20 







1-40 



• 5mm 









147 



The deflections obtained for the E. M. F. 0'02 D., and 01 D. 

 0'6 D. are evidently accidental. Neglecting these, it is evident 

 that no appreciable current passes through the electrometer 

 until the potential of its surface reaches 1*4 Daniell. This, it 

 will be remembered, is not the highest point of the curve show- 

 ing the deflection of the mercury in the electrometer. That point 

 is reached when the potential of the mercury surface is 0'9 

 Daniell. The point at which conduction begins is about the 

 point at which electrolysis begins. The collection of gas bub- 

 bles (before mentioned), when potentials of something over one 

 volt were used, indicate that electrolysis actually does take 

 place. The results of this investigation will prove that con- 

 duction through the electrometer begins about the same time. 



to 

























fn 

























ft 







rv 















& 























m 















ff 



s 



1 



2 7 



13 



4 1 



t 







































(ft 



rme I 

















































































n 







On April 1, 1887, a series of measurements was taken to de- 

 termine the exact point at which conduction begins. In this 

 series, before each observation, the sulphuric acid was run 



