Widely distributed in nature. American natural gas is about 85% methane. The earth's atm contains 0.00022% by vol. Major constituent of the atm of the outer planets (Jupiter, Saturn, Uranus, Neptune), exact figures in Landolt-Brnstein vol. III (Springer, 6th ed., 1952) p 59; G. P. Kuiper, The Atmospheres of the Earth and the Planets (University of Chicago Press, 1949). Pure carbon combines directly with pure hydrogen at temperatures above 1100° forming methane. Above 1500° amount of methane formed increases with temperature: Pring, J. Chem. Soc. 97, 498 (1910). Can be prepd from sodium acetate and sodium hydroxide, or from aluminum carbide and water: Matthews, J. Am. Chem. Soc. 21, 647 (1899); Carroll, J. Phys. Chem. 22, 148 (1918). Prepd commercially from natural gas or by fermentation of cellulose and sewage sludge: Cost, US 2583090 (1952 to Elliott Co.); Le Paige, de Dommartin, FR 994032 (1951), C.A. 51, 10836i (1957); Oswald, Golueke, Mech. Eng. 86, 40 (1964).