805.    EISENHUT, O., AND KAUPP, E.  [Radiographic Investigation of the System, Iron-Nitrogen.]  Ztschr. Elektrochem., vol. 36, 1930, pp. 392-404; Chem. Abs., vol. 24, 1930, p. 4207.

     Phase boundaries, solubility lines, eutectoid lines, and temperatures of Fe-N are definitely fixed by radiograms.  The results agree well with data from magnetic analysis.  The existence of 4 phases, a, γ, γ and e is established.  There is continuous absorption of N₂ during regular changes of the crystal-lattice constants.  Nitrogen martensite is formed.  Bibliography included.