1178 



10 percent of the ceils readied the constant valne of 50 millivolt 

 at 25° (CoHKN and Heldkrman's /-cells); 



70 percent of the cells leached the constant valne of 48 millivolt 

 at 25° (CoHKN and Hi'U.derman's |^-cells); 



20 percent of the cells reached the constant value of 47 millivolt 

 at 25° (CoHKN and HKi,DEKi\iAN's «-cells;. 



4. In determining the e. in. f. of these cells between 0° and 40° 

 as a function of temperature, Getman found for the 



«-cells : 



E^ = 0.04742—0.000200 (^-25) . . . . (/i) 



This is the same equation as has been given by Cohen and Helderman '). 

 Kor the ^-cells he found : 



A> = 0.04862—0.000201 (^-25) .... (5) 



These cells have not been investigated in this direction by Cohen 

 and Helderman. 



Finally Getman deduces for the y-cells : 



E., = 0.05047—0.0002437 (^-25) . . . . (C) 



which is the same formula as that found by Hulett. 



5. Concerning the behaviour of the cells above 40° Getman says : 

 "On raising the temperature of the cells above 40°, the temperature 

 coefficients weie found to undergo a reversal of sign. The values 

 of the e. m. f. given by the different cells when maintained for a 

 short time at a temperature above 40° were found to be quite 

 divergent. On prolonged standing at this temperature, however, 

 the divergence in e. m. f. was fonnd to disappear and final equil- 

 ibrium values agreeing within the limits of experimental error were 

 obtained. It was found that stabilization between 40° and 80° could 

 be brought about more quickly by maintaining the cells at a temp- 

 erature of 95° for several days. From the data obtained with five 

 cells which had been stabilized in this manner, an interpolation 

 formula ') 



E = 0.04280 + 0.000170 (t— 25) ....(/)) 



was derived by the method of least squares. On applying; this 

 formula to the data obtained with other cells, satisfactory agreement, 

 between the observed and calculated values of e.m.f. was secured". 



1) These proc. 17, 1050 (1915). 



2) Journal Amer. Ghem. Soc 39, note on page 1811 (1917). 



