By Isao Ishibe and Noboru Hirano.
The reducing velacities of the Johore hematite ore were tested by the various gas mixtures of CO, CO₂ and N₂. The reoucing gas, in which the sum of the partial preasures of CO and CO₂ was kept. at O.4 or O.6 atm. press., and the ratios of CO₂/CO were varied from zero to 2.5, Was passed through the sample in the rate of 100c per min. The temperature of the experiments were 700, 800, 90O and 1, 000°C The CO₂ in the exhausted gas passed through the sample was analysed every ten minutes, and thus the amount of oxygen from the iron ore was calculated from the diffbrehce between the volume of CO₂ cantained in the exhaused gas and the same in the reducing gas.
From the results of the above expedments we concluded as follows:
(1) The more the ratio of CO₂ to CO in the reducing gas increases, the more the reducing velocity of the ore deoreases, and at the lower temperature, a small variation. of that ratio effects more greately on the redncing velocity than at, the higher temperature. In general, when the value of C0₂/CO in the reducing gas approaches the value of CO₂/CO at the equilibrium condition of the reaction FeO+CO Fe+CO₂, the reducing velocities become very slow.
(2) Being referred our experimental results to the reports of W.A. Schlesinger, who had measured the temperatures and the ratios of CO₂ to CO in the furnace gases at the various heights in an iron blast furnace, the reducing velocities of an iron ore in the various heights of the stack of the aforesaid blast furnace were surveyed. Taking the tempetures, the partial pressures of CO+CO₂ and the ratics of CO₂ to CO equal to those measured by W.A. Schlesinger, we find from our experimental curves that the time taken for the reduction of the Johore are at 700°C is about 33 times of that at 1000°C in our experiment in which we passed 100cc. of the reducing gas per min, throngh 1g. of the sample of 1mm. size.

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The toughness of steel is usvally measured by impact test, and the work done in breaking the specimen of a definite form is expressed as impact value. However, thanks to the effort made by several investigators since 1926, the work done may, in addition, be shown as force-deformation diagram, if necessary. According to this diagram, it may be inferred that, even with two specimens of the same impact Value, one may have a comparatively great maximum force with a correspondingly little ultimate deformation, and the other, vice versa. Such an analytical consideration of the impact value is very important in the choice of materials. From this point of view, the forcedeformation curves of several alloy steels in differently heat-treated conditions were obtained in the present investigation.
The chief conclusions arrived at are as follows.: 1) Great impact values were generally combined with great ultimate deformations, but, for a definite impact value, there were considerable differences in the value of ultimate deformation. 2) While the impact value was comparatively little, the maximum force increased generally with it, but when the impact value became greater, the magimum force decreased with it. Similar to the previous case, for a definite impact vaule, the maximum force greatly differed. 3) The steel marked No. 6 in this note, when hardened and tempered properly, gave a very different form of the forcedeformation curve from those of the other steels of almost the same impact value, its maximum force being especially great. 4) No general relation was found between the maximum force and the Brinell hardness-number, but with those specimens of the same impact value greater than about 10kg-m as mersured in this test, these two quantities appeared to vary jointly in the same sense.

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The writer determined the heat of formation of Fe₄N by means of calorimeter. Then he calculated the molecular heat of Fe₂N and Fe₄N by appilylng the Neumann and Kopp's law and obtained the equilibrium epuations of the eystem: Fe, Fe₄N, NH₃, H₂ and Fe₂N, Fe₄N, NH₃, H₂ from the observed heat of formation of Fe₄N by the use of the Nernst's heat theorem. These equations agree satisfactorily with the equilibrium data obtained at high temperatures. Next he prepared various iron nitrides, the composition of which was accurately determined by the X ray photogram. He studied the electrochemical properties of the iron nitrides and made clear the passive state of them. He also tested the reversible property of the iron nitridecell.

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Kohei Taniguchi By the investigation of the characteristics of ateel mill chilled rolls for the object of improving their propertie, all the results of experiments tried until present on common cast irons are shown to be unsuitable for chilled rolls owing to the remarbkable difference in their properties. So the author deveced a prorer apparatus for this object to study this problem by reasonable method, and gained the following results.
(1) Influences of fifteen elements, namely, C, Al, Si, P, Ti, Co, Ni, Cu, S, V, Cr, Mn, Mo, Sn, W, are investigated in very wide rangest upon the surface hardness and the depth of chill which are so important for all chilled rolls, and are found to be most effective to add nickel with a little amount of chromet to gain hard rolls among those elements.
(2) In copsequence of the above resulte, various effects of nickwl and ohrome, and also combind effects of both elements were again further studied respectively, not only on surface problems but also on many physical and mechanieal properties of the inner grey part of the roll, and at last a very hard and strollg alloy chilled roll was invented, whose chemical composition lies between Ni 3.3, Cr 1.2%-Ni 4.3, Cr 1.6% and has its surface hardness oyer 90 in sclercope number, keeping always a constant chill depth equal to ordinary chilled rolls.
(3) Furthermore a plenty of this kind of heavy rolls has been practically cast in our foundry since that time, and used as tin plate finishing rolls (weight of one roll is 3, 800kg) or thin sheet finishing rolls(weght of one roll is 5, 717kg)act, for these several years gaining a splendid reaulta beyond expeutation.

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Hiroshi Sogo. The present writer carried out several researches on the subject from the accuracy and easiness of the practical veiw pts, and succeeded to get the reliable results to be shown in the following summary:
(1) In case of carbon and special steels, the oxidation method by nitric and hydrochloric acid is the most reliable process to get the accurate results while the evolution method is used to show very of ten too low results by the incomplete solubility.
(2) In case of pig irons, the evolution method is only useful to estimate small Part of sulphur in it and most part of sulphur is remained in the evolution flask. The application of the oxidation method by nitric and hydrochloric acid nearly always gives low results, and in such a case conaiderable amount of sulphur is found unestimated in the remaining residue with silica and graphite.
Then in this method the residue must be re-examined for sulphur, although the treatment is very tedious and liable to do failure.
Therefore in this work, the present writer tried and succeded to determine the total sulphur in pig iron by fusion method with the mixture of sodium peroxide and sodium carbonate (1:1).
And he has found this method is the most reliable and universally applicable one for determination of sulphur in pig iron
Now then the writer is wanted to add the experimental results with three different methods to emphasize his researches which were applied to the Swedish pig irons.

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