The Thermionic Emission of Platinum

The thermionic emission from round filaments and flat strips of platinum was measured giving a value for the work function of 5.32 volts and 32 amperes/${\mathrm{cm}}^2$ ${\mathrm{deg}}^2$ for the constant $A$. Highest possible vacuum conditions and heat treatment near 2000°K were found necessary for obtaining reliable results. The lack of such extreme heat treatment probably accounts for the abnormally high values of the constant $A$ formerly found. Special theoretical explanations for platinum appear no longer necessary.