230 JONES AND SCHUMB. 



electrodes were placed in each cell, thus permitting a test of the 

 reversibility of the electrodes, with results even more satisfactory 

 than in the case of the thallium electrodes. The difference between 

 any pair of electrodes in the same solution in no case exceeded a few 

 hundredths of a millivolt. The measurements were made against a 

 tenth normal calomel electrode instead of a normal electrode, because 

 it was believed that computation of the liquid junction correction 

 would be more reliable than if normal calomel electrodes were used. 

 The following tables show the experimental results: 



TABLE XI. 

 E. M. F. of CeU: Pt, h (soUd), 0.1 NKI, 0.1 NKCl, HgaClj, Hg. 



Observed E. M. F. 



TABLE XII. 



E. M. F. of Cell: Pt, h (solid), 0.05 N KI, 0.1 N KCl, HgsCk, Hg. 



Observed E. M. F. 

 25°C. 0°C. 



Pt Elec. No. 1 Pt Elec. No. 2 Pt Elec. No. 1 Pt Elec. No. 2 



TABLE XIII. 

 E. M. F. of Cell: Pt, I2 (soUd), 0.02 N KI, 0.1 N KCl, HgaCk, Hg. 



Observed E. M. F. 



Mean: -0.3200 Mean: -0.3114 



