Kurazo Fukagawa. Rigakuhakushi. -Known papera relating to the investigation of oxidation phenomenon for metals at high temperatures throughly studied are very large in their number. But they are only results that concerned the change of weight with time by the oxidation and these results are not sufficient to deduce the course of oxidation of metals. More-over, in the limit of my inquiring, paprs precisely discussed on the theoretical side of this subject have rarely been contributed. The known equation that expresses the oxidation velocity of metals obtained theoreti-cally and now geuerally used is as follew: where R is a some constant, in the weight of oxide-film, t the time, and this equation is taken as can hold in the whole range of oxidation. However, in my consideration, it may only hold in a very narrow range of the early period of oxidation and not in a whole range of oxidation as usually taken. Then I have theoretically considered this problem and arrived at a some conclusions, that is the oxidation of metals may be divided into the three stages, and the above expression may be considered as only applicable to the second stage in the course of oxidation of metals. The first step is the oxidation of metals in no presence of oxide-film on their surface. The third stage is its oxidation after some measurable oxide-film produced on the metal-surfaces. The uthor have theoretically derived the expression of the oxidation velocity of metal for this third stage. Practically the oxidation of this stage may be considered as important factor, if we are required to compare the non-oxidisability among many metals. The experimental teat for correctness of the expression derived by the anthor is now requisited. The author now confines himself on the investigalion of this point so that defers to future for its contribution.

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Hideo Nishimura,
-The constitution of the alloys of Al, Fe and Si from O to 30% of Si and from O to 30% of Fe has been investigated by the methods of thermal and micrographic analysis. Seven sectional diagrams whose iron contents are respectively 1.3%, 2%, 4%, 10%, 15%, 20%, 25% and 32% of Iron have been studied and from these sections an equilibrium diagram of this system in that domain has been determined. In this diagram there exist five primary crystallization surfaces of (Al), FeAl₃, FeAl₃.FeSi₂, and x (an unknown phase), the binary complex lines,
Liquid (Al)+FeAl₃
Liquid (Al)+FeAl₃.FeSi₂
Liquid+FeAl₃ FeAl₃.FeSi₂
Liquid FeAl₃.FeSi₂+Si
and three invariant points,
Liquid+FeAl₃ FeAl₃.FeSi₂+(Al) at 615°C
Liquid (Al)+Si at 578°C
Liquid+X FeAl₃ +FeAl₃.FeSi₂
Microscopically the ternary compound which has been called X, has been proved to be FeAl₃.FeSi₂.

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