On the Constant $A$ in Richardson's Equation

According to Herzfeld, the "chemical constant" of the electron gas is different in the high temperature region, where all actual measurements are carried out, from its value at very low temperatures. Hence the value of the constant $A$ in Richardson's equation must be different at high temperatures from the well-known low temperature value of 120 amp./${\mathrm{cm}}^2$ °${\mathrm{K}}^2$. The present paper gives a calculation of the high temperature value in terms of thermodynamic quantities and a numerical estimation of these.