AbstractThee.m. f.'s of the cells,Cd/CdSO4· 8/3 H2O(satd.)/Cd‐Hg(2‐phase), andCd‐Hg(2‐phase)/CdSO4· 8/3 H2O(satd.)/Ag2SO4(s)‐Ag,were observed at 25°, 30°, 40°, 50° and 60°C.The saturated cadmium amalgam electrode has been employed in evaluating the standard potential of the silver‐silver sulfate electrode, the activity‐product constants of Ag2SO4, and thermodynamic data for the reactionsCd + Ag2SO4= 2Ag + Cd+++ SO4−and2Hg + Ag2SO4= Hg2SO4+ 2Agin the temperature range of interest. The molar heat and free energy change for the formation of Ag2SO4at 25