The magnetostriction of iron-aluminium alloys has been measured by an apparatus designed by the present investigators in various longitudinal fields of less than 1200 Oersteds. The positive magnetostriction of iron gradually increases by the addition of aluminium, while the negative one decreases. All the alloys containing more than 5.90 percent of aluminium have only a positive magnetostriotion, and especially in the case of alloys containing more than 8.80 percent aluminium the magnetostriotion always increases with the magnetizing field or the intensity of magnetization; showing no maximum. The magnetostrictoin at a constant field of 1100 Oersteds shows a negative value, in the range of less than 5.3 percent aluminium content, while a positive value in the aluminium content above this percentage. And in the range of the aluminium content 11.5_??_13.2 percent the magnetostriction is very high; its highest value being 40×10^-6 of 13.14 percent aluminium alloy. These alloys may be excellent magnetostriction materials for a supersonic oscillator and have been called “Alfer” by the present investigators.

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In the same method of investigation that was applied on Zn by the senior writer, the study on Cu was commenced, and this is the first report. The characteristic feature of this method, differing from those which are generally applied by many Workers, exists in not accepting the assumption of the free electron in metals as the basis of the investigation. So, as the first step, the energy level of the valency electron in Cu was determined from the analysis of the X-ray spectral lines, to whose emissions-the valency electron probably associates. As these lines, the followings; Lβ'λ 12.989 Å, β''' 12.911 (shorter than Lβ1, L_II-M_IV, 13.026) and Lα'' 13.233, α'''' 13.176 (shorter than Lα₁₂, L_III-M_IVV, 13.301); were selected from those measured by Gwinner, Z. S. f. Phys., 108 (1938), 528, while the lines, Lβ'', 12.957, α' 13.277 and α''' 13.261, excluded, though they satisfy the condition for the wave-length above mentioned; and the reason for this will be described in a later paper. Accordingly, the line above selected are taken as due to the transitions, L_I-E_I, L_II-E₃ and L_III-E₂, L_III-E₄, respectively, and combined with Kα₂, K-L_II and Kα₁, K-L_III, respectively, obtaining the va'u s, K-E₁=661.417, 661.598, K-E₃=661.841 and K-E₄=661.896 Ryd. Thus the distances of the energy levels of the valency electron in Cu froni, K-level, are determined.

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The meta-stable lines in Fe-C diagram which are important for the theory of heat treatment of steels have been computed from free energies of ferrite, austenite, and cementite. The results obtained are given in Tables 1, 2, 3 and Fig. 2. The characteristics of the lines are as follows:-
(i) CSB line (γ-side line of A₃) has the characteristics not so much different from those supposed hitherto.
(ii) On GPA line (α-side line of A₃), the Concentration does not vary with the decrease of temperature below 6000. This suggests that the line may have no direct relation to Ar'' line.
(iii) GC line on which the free energies for α and γ are equal, is nearly parallel to Ar'' line.
(iv) LSM line (γ_??_α Fe₃C) is nearly parallel to Ar' line.

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Age-Hardening Processes can be divided, into two types: nonprecipitation and precipitation. In the former type, no precipitation, except Guinier-Preston Aggregates, may be observed until the hardness attains its maximum, while in the latter, precipitations may be detected from the early stages of the hardening pro_??_esses. Aging of the Al-Cu, Cu-Be systeme etc. in the lower temperature belong to the former and that of the Ag-Cu, Fe-Mo, systerne etc. belong to the latter. While the hardness-time curves of the Al-Cu alloy at the temperature between 0 and 70°C can be treated simply as hyperbolas with sufficient accuracy, that of precipitation type cannot be treated so. Let us define the degree of hardening as p=(H-H₀)/(H_s-H₀), where H_s, is the saturated hardness, H₀ is the as-quenched hardness and H is the bardness at the time t, measured with Vickers or Brinell Hardness number. Then, the linear relation between 1/(1-p) and t can be realized in the case of the Al-Cu alloy at the temperature noted above and the velcsity constant of age-hardening K can be obtained from the inclivation of this line. Therefore, the activation energy of the age-hardening can be calculated from the linear relation between log K and 1/T, where T is the absolute temperature. In general, Austin-Rickett's formula (in the case of the decomposition of Austenite in steel) 1/(1-p)=Ktⁿ+1 can be applied to both types of age-hardening, where n is nearly unity in the case of Al-Cu alloy, and is larger than unity in the case of the precipitation-type. We could deduce the Austin-Rickett's formula, in the case of age-hardening, from a few simple assumptions. We have found that the activation energy E of the age-hardening of Al-Cu alloy decreases as the concentration of Cu in the alloy decreases. The double peaks in the hardening curvei of Al-Cu alloy at high temperatures can be accounted for as follows; the first peak corresponds to the saturated hardeness of non-precipitation-hardening and the second corresponds to the maximum hardness as the result of the three-dementional growth of the aggregates.

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The standard electrode potentials of Magnesium and Manganese have been realculated by use of new thermodynamical data. The values obtained were 2.44 and 1.05 volts, respectively.

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The effects of the ignition temperature and the hydration temperature upon the hydration. velocity of the chemical pure lime were investigated by the dynamic method. From the results obtained, it was reccognized expectedly that the hydration velocity increases as the ignition temperature decreases. However, the hydration velocity decreases as the hydration temperature increases in spite of the opposite direction of relation anticipated from the general theory of the reaction velocity.

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On the adsorption equilibrium of water vapon by the chemical pure Ca(OH)₂, some isothermal and isobaric lines were determined by means of the statical method, and the following relations were obtained. The adsorbed amounts of H₂O by Ca(OH)₂, at 50°C and 100°C have Jaen found to be more than the values at 150°C and 200°C. From this observed relation between the adsorbed amounts and the adsorption temperature, it is concluded that the hydration velocity of lime must be increased as the hydration temperature decreases.

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The anthers gained the curves recorded by Sato's self-recording dilatometer on the hypereutectoid steel. (Its composition is 1.18% C, 0.23% Si, 0.28% Mn, 0.017% P, 0.023% S) The specimen was quenched in oil from 800°, after cooled slowly from 950° (lamellar pearlite specimen), it was quenched in oil from 950° (martensite specimen) or anneald (globular pearlite specimen). The Ar''-point of the former two change little by the holding time on the, quenching temperature. The Ar''- point of the latter one changes from 350° to 200° by the holding time, and end point of Ar''-transformation exists upon the room temperature. The Ar''-point rises according as the annealing time.

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The yield microstructure, bardness, true and apparent density, reaction time and the chemical composition of the metallic mass obtained were examined. The larger the amount of B₂O₃ in the charge mixture is, the higher the appropriate temperature giving the maximum yield as metallic mass rises, causing the yield as boron to be large, although the over-heating of the mixture lowers the yield both as metallic mass and as boron. If the amount of B₂O₃ in the charge mixture is constant, the higher the heating temperature is, the faster the reaction occures, and both density and hardness as well as the content of B, Si and Fe in the product increase, while the content of Al in the product and its porosity decrease.

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The authors carried out: a series of experiments on the temper-brittleness of silicon-manganese-chromium steel used in the construction of machinery. This investigation is concerned the effect of carbon on the temper-brittleness of two silicon-manganese-chromium steel. As the result of this investigation it was ascertained that the “First Temper-Brittleness” producing at tempering range of 453_??_525° is observed at above 0.25_??_0.30% carbon content, while the “Second Temper-Brittleness” occuring above 525° increases with carbon content.

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The au_??_hors investigated. the eifect of silicon 0.3_??_1.1 on the teaaper-britteness of silicon-manganese-chlomium steel the resalt of this investigation, there is ascertained that the rite of temper-brittleness is effected by the cooling velocity. and temperature of tempering. It becomes large with silicon content. The tempering temperature shoxing maximum rate of temper-brittleness due to air and furnace cooling is 600° and 650° respactively. In the case of the silicon-manganese-chlomiun steel containing 1% Cr and Mn, the elmnent Si promotes the “First and the Second Telpper-Britt'eness”.

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In this intestigation only the reaction between tin and nitric acid was tested. We examined the following phenomerd:
(i) Relation between the concentration of nitric acid and, corrodibility of tin during 1 hr. at room temperature.
(ii) The effect of stirring on the corrodibility of tin in 64.5% of and in 10% of nitric acid.
(iii) The effect of temperature up to 83° from room temperature on the corrosion of tie in 64.5% of and in 10% of nitric acid.
(iv) The effect of addition of NaCl or of MgSO₄ on the corrosion of tin in 10% of nitric acid.
(v) The effect of addition of organic substances such as dextrin and urea on the corrosion of tin in 10% of and in 30% of nitric acid.
(vi) Corrosion velocity of tin in 10% of and in 64.5% of nitric acid.
(vii) The passivity cf α-tin and β-tin in concentrated nitric acid at room ard at low tecurerature.

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