The time-strength of steel and cast iron under repeated tension was reported previously by the authers. In the present paper the similar experiments made on the specimens with U-shaped annular notches are reported. Summary of the results is as follows:
(1) The S-N diagram of a steel for the specimens with or without notches, if both axes are shown in logarithmic scale, consists of three straight lines, i. e., a horizontal line which represents the endurance limit, another horizontal line which represents the tensile strength, and a sloped straight line, the extent of which at N=1 is equal to the true breaking strength.
(2) The S-N curves of a steel for the specimens with and without notches intersect at N=10³-10⁵, and so the time-strength of a steel for the specimens with notches at N less than the value at the intersecting point, is larger than the time-strength for without notches.

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Permanent deformation of steel under slowly repeated load of comparatively great magnitude was measured and ε-N or γ-N diagrams and σ-ε or τ-γ diagrams were made where ε and γ denote the strain under tension and torsion respectively, N the number of cycles of repeated load, and σ and τ the axial and the shearing stress separately. Creep tests under normal temperature were also made to compare with the results of present tests under repeated load.
Summary of the results is as follows:
(1) Under repeated load, permanent deformation takes place when stress over yield point was repeated.
(2) Permanent deformations under repeated load and static load were compared; the latter is the larger than the former, but after a definite time the former becomes larger than the latter.

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Writers pointed out that, in the long time creep test of Hevea gum stock, the large part of the creep strain remained when the stress has been removed, and this permanent set arised only by the pure viscous characteristic or such a material. In order to find the value of η which is a coefficient of the pure viscous term, we must carry out the creep experiment and do successively the creep recovery experiment. The writers added the pure viscous term to the fundamental formula proposed in the previous paper, and derived the equations of the first creep strain, the first creep recovery strain, the second creep strain and the second creep recovery strain. Based upon the theoretical discussion, we caluculated the characteristic values of the Hevea gum stocks from the experimentally observed quantities at the temperature 20°C., 60°C. and 80°C., and discussed the relations of these values.

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The degree of graphitization of artificial graphites was estimated by the anodic swelling in electrolysis of sulphuric acid and Brodie's wet-oxidation. Moreover, the mechanism of the corrosion of graphite was discussed.
The results obtained are as follows;
1. Swelling test:
Swelled graphite by anodic treatment with sulphuric acid evolved oxygen when it was digested in alkaline solution, and the volume of oxygen suggested the degree of graphitization.
2. Wet-oxidation test:
Generally, lower graphitized carbon (amorphous carbon) consumed more than higer one (graphite).
In artificial graphite, however, contrary to our expectations, higher graphitized graphite consumed more than lower one.
The above facts availed for the estimation of the degree of graphitization.

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It was shown that corrosion resistibility of portland cement to mineral acids, under ground water and sugar solution, was increased and its alkali aggregate reaction was inhibitted both by the admixture of Beppu earth.
In this case, the decrease of free lime in hydrates of silica cement was quantitatively confirmed by lime absorbing test, thermal analysis, and X-ray spectrograph.

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The sample of papers containing 20-30mg. of water was weighed into a 300ml. flask containing 30ml, dry methanol. After agitation for 30min. at room temperature, the moisture was titrated with Karl Fischer reagent.
Based on data obtained, the moisture in papers appears to be completely extracted with methanol in 30min. agitation. Comparative data were obtained employing the weight loss method at 102°C.
Results obtained on several papers are summarized in Table 1. From these data it is seen that the moisture values by Karl Fischer method are somewhat higher than those by weight loss method.

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