Zn(CH4)2 + H2O = 2CH4 + ZnO; 2CH3MgI + H2O = 2CH4 + MgI2 + MgO.
In the laboratory it is usually prepared by J. B. A. Dumas' method (_Ann._, 1840, 33, p. 181), which consists in heating anhydrous sodium acetate with soda lime, CH3CO2Na + NaOH = Na2CO3 + CH4. The product obtained by this method is not pure, containing generally more or less ethylene and hydrogen.
Methane is a colourless gas of specific gravity 0.559 (air = 1). It may be condensed to a colourless liquid at -155° to -160° C. under atmospheric pressure (S. Wroblewsky, _Comptes rendus_, 1884, 99, p. 136). It boils at -162° C. and freezes at -186° C. Its critical temperature is -99.5° C. (J. Dewar). The gas is almost insoluble in water, but is slightly soluble in alcohol. It decomposes into its constituents when passed through a red-hot tube, small quantities of other hydrocarbons (ethane, ethylene, acetylene, benzene, &c.) being formed at the same time. It burns with a pale flame, and when mixed with air or oxygen forms a highly explosive mixture. W. A. Bone (_Jour. Chem. Soc._, 1902, 81, p. 535; 1903, 83, p. 1074) has shown that in the oxidation of methane by oxygen at 450-500° C. formaldehyde (or possibly methyl alcohol) is formed as an intermediate product, and is ultimately oxidized to carbon dioxide. Methane is an exceedingly stable gas, being unaffected by the action of chromic acid, nitric acid, or a mixture of nitric and sulphuric acids. Chlorine and bromine, however, react with methane, gradually replacing hydrogen and forming chlor- and brom-substitution products.
MARSHMAN, JOSHUA (1768-1837), English Baptist missionary and orientalist, was born on the 20th of April 1768, at Westbury Leigh, in Wiltshire. He followed the occupation of a weaver until 1794, but having meanwhile devoted himself to study he removed to Broadmead, Bristol, to take charge of a small school. In 1799 he was sent by the Baptist Missionary Society to join their mission at Serampur. Here, in addition to his more special duties, he studied Bengali and Sanskrit, and afterwards Chinese. He translated the Bible into various dialects, and, aided by his son, established newspapers and founded Serampur College. He received the degree of D.D. from Brown University, U.S.A., in 1810. He died at Serampur on the 5th of December 1837. His son, John Clark Marshman (1704-1877), was official Bengali translator; he published a _Guide to the Civil Law_ which, before the work of Macaulay, was the civil code of India, and wrote a _History of India_ (1842).