317,015. Soc. L'Air Liquide, Soc. Anon. pour l'Etude et l'Exploitation des ProcÚdÚs G. Claude, and Soc. Chimique de la Grande Paroisse Azote et Produits Chimiques. Aug. 8, 1928, [Convention date]. Separating gases by liquefaction.-Sulphurous impurities are removed from water gas by addition of coke oven gas containing ethylene and methane and cooling to liquefy the ethylene and if desired the methane in the mixture; the unliquefied portion is washed by the liquid and the impurities removed, and the gases are further cooled and rectified to obtain carbon monoxide and a mixture of hydrogen and nitrogen, which may be employed in the synthesis of alcohols and ammonia respectively.