Abstract
The Seebeck coefficients of thermocells of the type
were measured at temperatures near 1000°C. In these cells 
represents any of several oxygen‐inert gas or hydrogen‐water‐inert gas mixtures. It was found that the change in Seebeck coefficient corresponding to a change in the partial molar entropy of oxygen in the gas at the electrodes agreed closely with the values predicted from irreversible thermodynamic theory. Two principal assumptions were made in applying the theory to these cells: (i) that the transported entropy of the oxygen ions in the electrolyte was constant for the different gas mixtures used, and (ii) that gas‐solid reactions were at equilibrium at each electrode. The temperature dependence of the Seebeck voltage was found to be small.