348.    BRETEAU.  Hydrogention in Gaseous System Catalysis in Organic Chemistry.  P. Sabatier, D. Van Nostrand Co., New York, 1922, p. 186.

                 CO can be reduced in the cold, or better at 400°, to CH₄ in the presence of Pd sponge.

                 BREWER, R. E.  See abs. 920, 929.