We made studies on the method for determining the total water content, hygroscopic and combined, of the mineral substances. The analytical train consists of a purifying and drying train, a combustion tube-mounted in a high-temperature furnace and an absorption train. As oxygen is liberated and oxidizes ferro alloy and metal in samples by decomposition of the water contained in them due to the high temperature, the real water content can not be determined. Therefore, oxygen as the sweeping medium which passes successively through the train, was selected in order to avoid any such reaction occurring within the train. On this method the blank test was the most important and was investigated to establish satisfactory results for determining the total water content in the mineral substances. The results presented also confirm the reproducibility of the method described herein.

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The results of the combined alternating bending and torsional fatigue tests on the specimens without notches were reported by the auther previously. In this paper the similar experiments made on the specimens with V-shaped circular notches are reported. Summary of the results are as follows:
(1) The ratio of the torsional fatigue limit to the bending fatigue limit increases with notches, and the increasing rate is larger in high carbon steel than in low carbon steel, but it is very small in cast iron.
(2) Excepting the case of mild steel, the fatigue strength of notched specimens under combined alternating bending and torsion can be represented by Equation (2) in this report. In mild steel the fatigue strength is lower than by Equation (2).
(3) Fatigue fractures of notched specimens are somewhat analogous to those of smooth specimens in the previous report.

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On the stress determination of machine parts, it is necessary for us to know not only tensile stress but also compressive stress. Of the tensile stress determination by brittle coating we have reported in the previous paper. For measuring compressive stress, we utilized the phenomenon that the coating on the surface of machine parts under load relaxes within an hour. That is, the machine parts are loaded in compression and during this condition is maintained the relaxation proceeds in the coating. After the duration of about 50 minutes the coating becomes free from stress. On leaving the load, the machine parts tend to revert to the initial condition and then the tensile stress occurs in the coating. Thus minute cracks break out in the coating as in the case of direct method (tensile stress determination). The mode of qualitative as wel las quantitative analysis of compressive stress is analogous to that in the case of tension. A few of examples experimented are shown.

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The clay body processed as usual was pugged with a laboratory pug mill. The pugged mass was then subjected to uniform pressure in a cylinder filled with oil by compressing the latter with a piston whose displacement being measured by a dial gauge. From the pressure-displacement curve thus obtained the quantity of air contained within the mass was estimated.
From the results it was concluded that
(1) the quantity of air occluded decreases in proportion to the degree of evacuation.
(2) the evacuation is effective in inverse proportion to the thickness of clay-slab supplied to the vacuum chamber of the mill.
(3) the time necessary for the evacuation is the scores of seconds, generally less than 30 seconds.
It was observed that the operation of vacuum pug mill under comparatively higher pressure rather leads to the increase of the quantity of air. This tendency was found to be true, for example, to the pressure as low as 500mmHg. Hence for the effective de-airing the evacuation lower than 500mmHg would be necessary.

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