382 Messrs. Wright and Thompson on the Determination of 



During 1st 1 

 minute, j 



-23 



-11 



4-2-7 



4-3-4 



During 8th 1 



minute, i j 



-1-6 



- -4 



+ 1-4 



4-2-2 



During 15th 1 

 minute. 



-1-3 



- -1 



4- '7 



4-l'2 



Average of 

 all obser- 



\ 



-1-6 



— '5 



+ 1-5 



4-2-1 



vations. 



J 













General average 



.... -+4. 





The mean of this and the preceding experiment gives —'2d, 

 an amount evidently quite negligible in comparison with the 

 fluctuations in the value of the net B.M.F. in operation in 

 the several series of observations ; and hence indicating that 

 the E.M.F. of a cell set up with zinc- and copper-sulphate solu- 

 tions of the same strength, amalgamated zinc and electro-copper, 

 is really independent of the solution-strength within the limits 

 of observational error. 



Using the same solutions in the same way the following 

 values were obtained, showing that the E.M.F. really does 

 rise perceptibly with the solution-strength when amalgamated 

 copper is substituted for electro-copper, or when electro-zinc 

 is substituted for amalgamated zinc : — 



Amalgamated Zinc and Amalgamated Copper. 



During 1st "1 - 



minute. 

 During 8th 1 _.,- 



minute. J 

 During 15th 1 _.g 



minute. J 



+ 15-3 



4- 7-7 

 4- 5-2 



+91 



+ 1-3 







+ 130 

 + 5-7 



+ 3-8 



Average of I 

 all obser- L —'7 

 vations. J 



4- 9-0 



4-2-7 



+ 6-5 



General average = 4-4*4. 





Electro-zinc and Electro-copper. 



During 1st 

 minute. 



During 8th 



minute. 



During 15th 



minute. 



} +0-9 

 } +1-8 



+6-3 

 +4-0 

 +2-9 



+8-2 

 +5-7 

 +3-4 



+7-2 

 +4-4 

 +3-5 



Average of 

 all obser- 

 vations. 



} + , 



+4-2 



+5-6 



+4-8 



General average = 4-3*7. 



