230 



made. Two of the legs were filled with mercury and the third was fiiied 

 with cadmium amalgam. Connection was made to the amalgam terminal 

 and to one of the mercury terminals and current passed until the cells 

 were polarized. Measurements were made by means of the potentiometer, 

 and it was found that the E. M. F. between the unpolarized mercury ter- 

 minal and the cadmium terminal was normal, while the polarized mercury 

 terminal gave a very small value, showing the polarization to be at the 

 mercury terminal. Measurements were made between polarized cells and 

 unpolarized cells by connecting the two cells together by means of a 

 siphon filled with cadmium sulphate solution. In every case it was found 

 that the polarized mercury terminal gave low values, while the polarized 

 cadmium terminal gave normal values when connected to unpolarized mer- 

 cury terminals, never deviating more than could be explained by concen- 

 tration and temperature effects. 



A cell (5) was short circuited for some days and part of the mercury 

 was removed with a pipette, washed and filtered through a pinhole and 

 made the mercury terminal of a new cell (6) from which the mercurous 

 sulphate was omitted. The E. M. F. was measured from time to time 

 and the recovery noted. The following table gives the results. 









E. M. F. 





(5) 



(6) 



March 

 March 



9, 

 10, 

 10, 

 12, 

 13, 

 14 

 15 

 14 



8 

 26 

 24 



5:15 p. m 



9:00 a. m , 



0.1308 



.1320 



.1363 



.1488 



.1675 



1.0222 



1.0242 



1.0146 



1.0177 



1.0189 



1.0150 



0.1290 

 .1307 





3:45 p. m 



.1310 



March 



9:20 a. m 



.1339 







.1322 







.1317 







.1335 







.0691 







.0533 







.0637 







.0462 









The above table shows that cell (5), which contained mercurous sul- 

 phate, recovered its E. M. F. in a few days, while (6) remained polarized 

 for six months. The results show the E. M. F. in March to be greater 

 than the later values. This may be due to the cadmium sulphate solution 

 not being concentrated in the early observations or to some constant error 

 of the potentiometer. The table shows that the polarization is due to 



