Mineral graphite occurs in the following shapes (Dana's book): (1) Six-sided tabular or Slaty. (2) Foliated, Scaly, Laminae. (3) Columnar. (4) Radiated. (5) Granular. (6) Earthy. (7) Globular (rare). (8) Vein (rare). In cast iron the sections of (5), lump graphite, and of (2), flake graphite, are most predominantly observable.
  I think the graphites of various shaps grew all from nuclear small lump ones up. Six-sided columnar crystals will result under the conditions of free growth. But as there exists incessant relative motion between graphites and molten metal the glaphites, which are very weak at high temperatures, will break by slipping along the basal plane and the edges will be smoothed. Round slaty graphites are thus to be formed. Theae slaty crystals, however, become all curved because graphite is very flexible and non-elastic at high temperatures (Dana's book). The sections of these curved slaty crystals are shown as flake graphites under the microscope.
  The crystals which do not slip grow into columnar or granular shape up, which sections are shown as lump graphites.
  These lump graphites (extremely flexible and non-elastic at high temperatures) have tendency to become globular due to their own surface tension. In ordinary case, however, surface tension is not sufficiently large to make globular graphites. When Mg- or Ce- treated molten cast iron solidifies the disolved Mg or Ce becomes super-saturated and separates as vapour out, and the vapour is instantly adsorbed by growing graphites. The surface tension of the graphites is assumed to increase by the adsorption making the crystals globular.
  Only minute addition of Mg or Ce may be sufficient for the vapour-adsorption modifying the surface tention. Low content of Sand P are desirable for the cast iron as these elements lessen the quantity of adsorption. The fact that the Mg- treated molten iron which will become globular on inoculation using Fe-Si becomes flake graphite cast iron on inoculation using graphite powder may be explaind by previous adsorption of Ce or Mg vapour by added graphite powder. Mg and Ce are first dissolved in molten metal and separate later on solidifing out. All observed facts can be explained by this theory.

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  Investigated the size of clay particles of Kasuya (Fukuoka Prefecture) and Goto (Nagasaki Prefecture). The testing method applied the falling time of the particles by Stoke's law, which calculated from the fallng velocity of the fine clay particles and obtained 1∼200 micron size in clay particles.
  It filled up to the constant hight with the constant volume of clay water in vessel, and agitated it, then outflawed by syphon in every desired time. And then investigated the separated particle size by microscopic examination in the purpose of inspecting of it which separated particles by Stoke's law, with the scale of micrometer, whether shows the same result or not.

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  By lack of good quality pig iron or coke, many defects are introduced by the molten cupola cast iron. In order to prevent these defects, the hot blast cupola is adopted. One of the profits of this cupola is to be able to decrease the sulphur content in cast iron.
  Results of the hot blast operation are reported, and cause of the sulphur-decreasing are discassed, and we concluded as follows :
  1. Decreasing of sulphur by low coke ratio.
  2. Oxidation of the molten metal decreased by the reducing atmosphere in the furnace.
  3. FeO in the slag decreased by (1), (2) and desulphurization of slag increased.
  4. Desulphurization of slag increased by the high temperature in the furnace.
  5. CO per cent. increased in the furnace, and Mn loss decreased, and consequently desulphurization reaction accelerated.

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