Micrographic Examination of Cast-Iron in the " Graphitized" Condition. O. KR6HNKE. (Metallurgie, vii, 674.)--A peculiar decomposition of cast-iron tubes converts them into a soft dull gray or dark brown mass, somewhat similar to graphite, while they retain their external shape. There are various methods of causing this change, and the converted material has a specific gravity of approximately 2, and can be cut with a knife. Tubes of various compositions have been buried in the earth and then, at different degrees of conversion, examined micrographically. One specimen with a normal composition: total carbon 3.81 per cent., graphite 2.96, sulphur 0.097 , manganese 0.55, silicon 2.33 , phosphorus 1.85o, iron 91.82 per cent., was converted to this composition--total C, 9.85 per cent., graphite 8.83, S o.518, Mn I.IO, Si 4.25, P 3.60, Fe 68.6 per cent. Apparently the changes are: (I) Pearlite disappears, but only the ferrite is dissolved from it; (2) the graphite remains, but is converted into a peculiar grayish-white or white modification according to the extent of the conversion (Graphitierung) ; (3) cementite and the phosphide eutectic remain unchanged. White iron containing no graphite, and wrought iron tubes, do not appear to undergo the change. It seems, therefore, that the destruction of the tubes is caused by electrolytic action set up between the graphite and the other constituents of gray iron.