Mallet, Comptes rendus, 1867, 64,' p. 226; 1868, 66, p. 349); by the electrolysis of solutions of sodium hydroxide, using nickel electrodes; by heating calcium plumbate (obtained from litharge and calcium carbonate) in a current of carbon dioxide (G.
The Kassner process for the manufacture of oxygen depends upon the formation of calcium plumbate, Ca2Pb04, by heating a mixture of lime and litharge in a current of air, decomposing this substance into calcium carbonate and lead dioxide by heating in a current of carbon dioxide, and then decomposing these compounds with the evolution of carbon dioxide and oxygen by raising the temperature.