In this paper is described the atom arangement of the supercooled structures of β-phase, named β₁ β' and γ'. and the relationship among these metastable phases. The β-phase crystallizes in a body centered cubic lattice, disordered; β₁ a body centered cubic, ordered; and γ' a hexagonal close-packed. β' can transform to γ' by mechanical deformation and comes near to γ' with the addition of Mn. It is reasonable that the crystal structure of β' does not strikingly differ from that of γ', so the author supports the opinion that β' crystal is destorted a bit from γ'. With addition of Mn β is supercooled easily to the room temperature. This β₁ transforms to γ' by mechanical deformation.

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With molton aluminium, the diffusion of aluminium on carbon steel and special steel at various temperatures between 670° and 800° for 1_??_10 minutes was investigated. From the surface layer of the diffused specimens, the measurement of the depth of penetration, microscopic examination as well as hardness test were carried out. The obtained results are summarized as follow: The diffusion of aluminium on carbon steel differs according to the dipping temperatures and times.
The rate of diffusion increases as the temperature but it is remarkably retard_??_d according to the increase of carbon contents of the specimens. The relation between the contents of nickel and chrom which effects diffusion, is not obvious. In general, the diffusion of aluminium is markedly retarded by the increase in large amounts of nickel content and ison the contrary, accelerated by the addition of large amounts of chrom content.

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The promoting effects of the third elements have been studied by many authors, and it was accepted that Si and Al are the most effective. But since it is not yet clear, which is the more effective, the promoting effect of them-was determined under same conditions up to the concentration Ca. 3%. As a consequence, it is acknowledged that Al is more effective than Si in all concentrations and that there are linear relations in log t and Si or Al-%. (t:time of graphitisation (in minutes)

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The relation between the finishing grade of the metal surface and its friction was studied. The results obtained are:
(1) By Aluminum, copper and silver the surface friction decreases by increase of surface smoothness; the s_??_-called bearing materials as Al-Sn alloy, Cu-Pb alloy and cast iron do not take, a high finishing than the grade of the shaft.
(2) The friction curve of the silver surface is reverse to the curve of cast iron, (Fig. 1).
(3) Vertical sliding to the finishing direction is more comfortable than the parallel sliding in all metals and alloys.
(4) The surface preparation of copper, aluminium, silver and iron is not effec_??_ive, but is important on the ductile materials as bearing alloys.

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The results of wear test on some kinds of carbon steels and cast iron in combination with carbon steels and cast iron prove that the wear loss is proportional to the hardness variation of the rubbing surface. The hardness of rubbed surface is measured by the microscopic Vickers hardmeter on 100 gram load. The surface hardness of steel increases on the low carbon side and decreases on the high carbon side. This phenomenon resembles the oxide film hardness reported in the 2 nd report. The oxide film generally protects abrasion but free oxide flakes or grains accelerate wear and soft material that produces hard oxides can easily wear out harder steel. As a consequence of the inordinate hardness increase on the rubbing surface of carbon steel In certain conditions, it is supposed that there are not only simple plastic deformation and oxidation but also quenching by radical heating and cooling.

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There are many friction parts in a searing machine for household use and the wear by friction influences the action, sound and vibration of it. The influences of the kind, microstructure, case hardening and surface roughness of metals upon the wear of friction parts were tested; the results are briefly summarised as follows:
(1) No great difference was noticed between the pearitic cast iron and ferritic cast iron in the amount of wear in wet friction.
(2) In the cases of water quenching after the heating by high frequency current and hard chromium plating, the deformations are less than by water quenching after carburization.
(3) The wear resistance properties of the oilless bearing metal by powder métallurgy are similar to that of cast iron but much better than that of brass and Cu-Al alloy casting.
(4) The fine finishing of surface of friction parts is required to diminish the wear, particularly that of the beginning of friction.

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Researches were made on the corrosion of Ni, Cu, Cu-Ni, Zn and Ag-plating, solder and phosphate-coat with the solutions of distilled water, NaCl Bordeux mixture, formaldehyd DDT, formic acid and sod. arsenite.
Found to be resistant are, Zn-plating and phosphate coat in distilled water; Zn-plating in NaCl solution; Zn-plating and Cu-Ni-plating in Bordeux mixture; and Zn-plating and Cu-Ni-plating are resisting in formaldehyde solution. They do not all rust in the DDT solution, and sod. arsenite solution, but do in the phosphat-coat solution. In the formic acid solution, all are soluble.

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In the present paper, the results of tin corrosion in phosphoric acid, acetic acid, sodium hycaroxide, and some neutral salt solutions are described.

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A suitable condition for the blue coloration of ammonia in alkalish solution with phenol and hypochlorite was studied by using Pulfrich's photometer. Applying this coloration, a colorimetric determination of nitrogen in iron and steels has been studied after iron and other metals were separated by using sodium hydroxide, and accurate results for several kinds of steels were obtained. The time required for this analysis is about 26-52 minutes.

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The blue color of ammonia in alkalish solution with phenol and hypochlorite gives the maximum coloration in the concentration of 0.3 N sodium hydroxide solution. This color reaction was applied to the, determination of nitrogen in iron and steels, and accurate results were obtained.

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