188.    ---------------. [BÉNARD, J.] [Variation of the Composition of Ferrous Oxide.]  Bull. soc. chim. France, 1949, D, pp. 109-116; Chem. Abs., vol. 43, 1949, p. 6901.

                  Composition of FeO corresponds exactly to the theoretical for FeO (77.7% Fe) above 750°.  Fe3O4 attains 75.9% Fe at 1.100° and does not change with increase in temperature.  At 580°, an equilibrium exists between the 3 phases FeO.  Fe, and Fe3O4 corresponding to 76.9% Fe.  The apparatus is described together with experimental technique.  Reviews literature.

                   ---------------.  See abs. 478, 1279, 2275.