With the recent progress in industry, the materials are often imposed to high temperature and severe stress. In designing machine parts which are used under such conditions, the creep strength has been used as one of the significant characteristics of the material. As the majority of machine parts is however subjected to dynamic loading, it is desirable to have some experimental data of the strength of materials under such conditions.
In this paper, a newly designed fatigue testing machine, which is available for the combined stresses of static tension and alternating bending, is introduced. It is especially suited for testing turbine blades in actual service. Some experimental results are shown.

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The double notch in this test consists of primary and secondary notches. The secondary notch is situated at the root of the primary notch. Fatigue tests were made on specimens having such double notches. From the results of experiments, the following conclusions are obtained.
The notch factor of a double notch β_{K1, 2} is equal to the product of β_K1 and β_K2, where β_K1 and β_K2 are the notch factors corresponding to the primary and secondary notches respectively. But when the sharpness of the two notches becomes close to each other, β_{K1, 2} becomes less than the product of β_K1 and β_K2. Thus designers should pay attention to the fact that the fatigue strength of the materials with double notches becomes essentially lower than that which would be expected from each notch.

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By the fatigue tests of bicycle spokes subjected to repeated tensile loads, the following results are obtained:
1. Since the fatigue fracture of bicycle spokes begins with a crack at the root of the head, the shape and condition under which this part contacts with the spoke hole in the wheel hub seriously affect the fatigue strength.
2. The surface of the fracture on the head of spokes in this test shows the same appearance as that which actually occurs, but is quite different from the one obtained by static tensile test. The reason is that the fracture in the latter test occurred by shear stress.
3. The fatigue limit of sample spokes (240kg being the static tensile strength) was 85kg, and corrosion with acids, sea water etc. decrease the fatigue strength.

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Formerly some informations were given by the present authors concerning with an electric hygrometer devised originally by them. The apparatus is applicable and effective to measure the permeability of moisture of various kinds of materials in sheet form.
As the anti-moisture properties are very important for packing materials the electric hygrometer was applied for the purpose of measuring moisture permeability of those materials this time. The method of the measurement enables us to observe moisture penetration moment by moment and to judge the degree of the moisture permeability of a specimen within one hour, i.e., the timeamount to only one 70th of that required in ordinary weighing method.

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The mean Vickers hardness number H_m of thinly plated metals can be experimentally expressed by the following relation:
where, H_p, H_b: V.H.N of plated and base metal respectively.
δ: thickness of plated layer.
T: apparent depth of indentation.
K: constant decided by plated and base metal.
The true hardness number of a plated metal can be conveniently extrapolated by this expression with the measured values H_ms.

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The fluidities of clay suspensions for various grog contents were measured by Green's viscometer. Using these clay suspensions, solid casting was performed; casting ability, drying shrinkage and firing properties were observed.
From these observations, we tried to determine the relation between the fluidity and the casting characteristics of slips.

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