According to many reports published on the impact strength of rocks, the Page impact test is usually adopted, while the impact flexure test is seldom used.
The authors have designed a Charpy-type flexure testing machine with a small impact energy, 0.02kg·m, in order to make it possible to test such a brittle material as rock, and have carried out the tests with this machine on sandstone, marble and granite.
The results obtained show that this method affords a possible means of determining the impact strength of rocks.

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This paper deals with the experimental research on the effects of change of wire drawing condition on hardness distribution over the section of drawn wire.
Using a Micro-Vickers hardness tester, we tried to investigate the hardness distribution over the cross section of three kinds of carbon steel wires and a brass wire, drawn under several kinds of drawing conditions, as well as the gradual change of hardness over the longitudinal section of carbon steel wires under plastic deformation with half drawn specimen.
As the results we have make it clear that the wire with uniform deformation as possible will be obtained by following methods of drawing:
(1) with the die of larger radius of curvature of drawing surface than with the die of smaller radius,
(2) under high reduction of diameter than low reduction.

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For the purpose of direct indication or recording of humidity, it is reasonable and convenient to use the selenium hygrosensitive elements, formerly developed by the present authers, Saito and Serizawa, inserted in A. C. circuits. In this case, requirements on the characteristics of the elements must be somewhat different from those used in D. C. circuits.
In this paper, manufacturing methods and properties of such purposive hygrometer elements are reported in the first place. Then two different types of electrical instruments directly indicating humidity are introduced. One is A. C. resistancemeter type and the other is automatic balancing A. C. bridge type. They are selectively applicable for the purpose of humidity measurement.

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On the observation of fatigued tirecord under a microscope, it was observed that the ruptured fibers applied by the T-type fatigue tester splited longitudinally in several cracks. This phenomena resembles to that of cords fatigued in the tire and proves that the T-type fatigue tester is more proper as a fatigue tester of tire cord.
The mechanism of the flexing fatigue is seemed to be different from that of the stretching fatigue. Therefore, cord must be made from raw yarn having suitable properties according the practical use.
It is desirable to increase the value A and K, obtaining by the characteristic fatigue test. A has meaning of tensile strength, but K has direct relation with H which means the innate elastic properties of yarn. It was found the following relationships: H∞1/K_s and H∞K_f, where K_f and K_s are the value of K respectively in the case of flexing- and stretching-fatigue. The value of A is opposit to that of H; the increases of the value of A (∞K_s) is favor on stretching fatigue. On the contrary, the increase of A (∞1/K_f) and is not favor on flexing fatigue. But by relaxation after stretching in the process of spinning viscose rayon, it can be able to increase the value of K_f, without decreasing the value of A.
Because the values of A of “BX” and “Supra” are great but the values of K_f are small, there fibers are not suitable for tire cord. “Super Cordura” may be said new type of high tenacity rayon having great A and K_f.

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Tensile creep tests were carried out on polymethyl methacrylate, by use of the authors' creep testing machine for plastic materials.
Results obtained are represented as strain (ε)/time (t) curves or the so-called creep curves, with an experimental formula, i. e.,
ε=ε₀+Atⁿ where A and n are respectively the material constant dependent of the test temperature and the applied stress.
Some rheological considerations are taken on the result and the influence of test conditions upon creep properties of the test specimen are also discussed.

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We made the tension tests about the specimens of annealed mild steel with various circumferential notches, and made σ-q diagrams about each specimen, where σ indicates the tensile stress and q indicates the area contraction corresponding to every stage of loads during the tension tests. And so we required the relation between the sharpness of the notch and tensile strength σ_B, breaking stress on final area σ_T or area contraction ψ.
Summary of the results is as follows:
(1) Tensile strength σ_B increases when the notch becomes sharper, and approaches to cirtain maximum value.
(2) Area contraction ψ decreases when the notch becomes sharper, and approaches to cirtain minimum value.
(3) The ture breaking stress on final area σ_T increases at first but thereafter it decreases when the notch becomes sharper. For this reason we explained using the stress distribution in the section of the necked portion when the specimen breaks.

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