and the Weston formal Cell. 



2^ 



Table V. 



Giving the observed E.M.F.'s at 0° C. of cells containing 

 14 per cent, amalgams, one of which was chilled and 

 the other slowly cooled. 



The E.M.F.'s = 1-01840 v. 4- values given in Table. 





14 per cent, slowly 

 cooled. 



14 per cent, 

 chilled. 



1st day 



+000038 v. 

 40 

 40 

 40 

 40 

 41 

 41 

 41 



4-0-0060(5 v. 

 656 

 686 

 691 

 693 

 696 

 695 

 694 



2nd , 



4th „ 



5th , 



6th „ 



10th , 



15th , 



21st 





The results show in a decisive manner that differences of 

 very considerable amounts may arise owing to differences in 

 the rates of cooling of the amalgams. The 14 per cent, 

 slowly cooled amalgam cell had an E.M.F. only 5 parts in 

 100,000 greater than that of a cell containing a 5 per cent, 

 amalgam, whereas the 14 per cent, chilled amalgam had an 

 E.M.F. which is considerably greater than that of any cell 

 with 14 per cent, amalgam which is reported on in Table IV. 



It was thought possible that the chilled and slowly cooled 

 amalgams might differ owing to local differences in con- 

 centration other than that mentioned on p. 260. When a 

 14 per cent, amalgam — or one of higher concentration — 

 is completely melted and slowly cooled in a water bath, the 

 soUd crystals which first separate out arc lighter than the 

 mother liquor, and rise to the upper portion of the amalgam. 

 Hence, after the amalgam has cooled, it is probable that the 

 concentration of the cadmium in the upper portion is greater 

 than in the lower portion. When a 10 per cent, amalgam 

 was melted in a long glass tube and cooled slowly, this 

 difference was detected by inspection, the lower half of the 

 amalgam having an appearance approaching that of liquid 

 mercury, while the upper portion had a frosted appearance. 

 To test whether there was any marked difference in the 

 electromotive properties of the two ends a platinum wire w r as 

 sealed through the middle portion of a closed glass tube, 



