3331.     TAYLOR, G. B., AND STARKWEATHER, H. W.  Reduction of Metal Oxides by Hydrogen.  Jour. Am. Chem. Soc., vol. 52, 1930, pp. 2314-2325; Chem. Abs., vol. 24, 1930, p. 3944.

        Method is described for studying the rate of reduction of metal oxides at temperatures below 500° in which the volume of H₂ consumed is measured.  The oxides of Ni, Cu, Fe, and Zn were studied by this method.  Fe₂O₃ gels are reduced to ferroso-ferric oxide at 350° and to metallic Fe at 450°.  Ignited Fe₂O₃ is not appreciably reduced at 350° but goes to metal at 450°.  Foreign metal interfaces with Fe₂O₃ accelerate the reduction of Fe.  Al₂O₃ and Cr₂O₃ greatly retard the reduction of ferroso-ferric oxide.  Fe₂O₃ gels show the glow phenomenon in H₂ at fairly low temperatures but not in air or vacuum.  The thermodynamics of ZnO reduction in the presence of Cu are worked out, giving an explanation of the formation of a-brass.

        TAYLOR, H. G.  See abs. 3305a.