and the Weston Xormal Cell. 267 



outer shell o£ the amalgam is of lower cadmium concentration 

 than the mean concentration. With continued diffusion the 

 outer skin of the amalgam will become richer in cadmium, 

 and thus the E.M.F. o£ the cell will increase. Such increases 

 are recorded in Table VI., and have been previously observed 

 by Jaeger 2 and by Bijl 6 . 



If, after a cell has been hermetically sealed, a previously 

 slowly cooled amalgam (forming the negative element of the 

 cell) is raised above its first transition temperature, but not 

 above the second, subsequent chilling of the amalgam does 

 not, in general, result in an increased E.M.F., but a lowering- 

 may result. A cell containing a 14 per cent, amalgam was 

 raised to 50° and then chilled with ice-water ; its E.M.F. 

 was thus lowered from 102260 v. to 1 02220 v. This 

 lowering- was no doubt due to the outer shell of the amalgam 

 becoming even less concentrated in cadmium than before. 

 However, in such experiments it was repeatedly observed 

 that the rate of increase of E.M.F. of the cell with time 

 was accelerated by such treatment. 



After remaining in ice for 30 days, the cells with the 

 chilled and slowly cooled amalgams (Table VI.), and others 

 containing from 2 to 10 per cent, cadmium amalgams, were 

 gradually increased in temperature, and the E.M.F/s 

 observed at intervals of 5° up to b'5°. The temperatures 5° 

 and 10° were maintained very nearly constant for about 

 1 hour, and all other temperatures were kept constant for at 

 least 1 hours. The results are given in the following 

 Table (p. 268). 



After the cells hail been raised in temperature to 65° ( !., 

 they were again immersed in ice. and after 14 hours a 

 comparison of their E.M.F/s led to the results given in the 

 last column of Table VIII. (compare with Table III.). 



"With the exception of these final values at 0°,the E.M.F.s 

 &c, given in Table VIIT. have been plotted, and the resulting 

 curves appear in tig. 3 (PI. III.). The dotted portions of the 

 curves were not experimentally realized, as the cells were 

 unstable at temperatures very near to the first transition points 

 of the amalgam.-. 



A comparison of the effects of temperature changes on 

 chilled and slowly cooled amalgams is now of interest. The 

 whole of the slowly cooled amalgam cells tabulated in 

 Table VI. were raised in temperature from 0° to 05° C, 

 but it is not necessary to give all the results. The following 

 (Table IX.) is a typical case. Here, the three amalgams in 

 one vessel were 10 per cent., 17 per cent, chilled, and 



