127. BARKER, M. E., Catalysts Suitable for Various Purposes. United States Patent 1,936,563. Nov. 21, 1933. Chem. Abs., vol. 28, 1934, p. 867.

An alloy containing Cu, Fe, and Mn is treated with an acid such as HCL, and the substances formed by reaction of the acid on the surface of the alloy are calcined to produce mixed oxides.