Layered volcanic ash soil is distributed over Otoshibe region in Hokkaido. The authors have studied into soil water movement in the grazing land of orchard grass and clover at Otoshibe. The test field lies on gentle slope (3°30') surrounded by small streams on both sides. The soil profile consists of three layers comprising SL (0-16 cm), S (16-50 cm) and CL (50-75 cm) strata. The top layer, the color of which is 75 YR 2/3, contains plagioclase, hypersthene, glass, and much humus. The next and 3 rd layers are 10 YR 6/6 and 10 YR 8/2, in color respectively and both layers contains plagioclase, hypersthene, and hornblende but no humus. The fourth layer, the color of which is 2.5 Y1/10, contains again much humus and glass. Permeability values of these strata are 4.6×10^-3 cm/ s, 1.2×10^-1 cm/s and 5.0×10^-3 cm/ s, respectively, and water retention abilities at pF 2.0 are 65%, 24% and 91%, by saturation percentage. Values of porosity are 61%, 61% and 78%, and values of bulk density are 1.04, 1.05 and 0. 54, respectively.
An infiltration test was carried on 8 kinds of test columns which were made of two or three layers of disturbed or undisturbed soil sampled at Otoshibe. Another infiltration test on a ploughed or nonploughed field was also carried out in this investigation.
The results obtained are as follows.(1) In the top layer, water content reaches 40-50% when much water infiltrates from the soil surface. This value of water content exceeds the minimum value of water holding capacity of this soil.(2) In the sand layer, there remains 20-25mm of water 24 hours after 100 mm of water infiltrated from the soil surface. After the lapse of 24 hours, water was kept discharged from the bottom of each column. Some water which gets to the sand layer flows through the kuroboku layer while some water flows horizontally along the surface of the kuroboku layer through the sand layer. Consequently the part having the minimum water holding capacity gets longer.

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In this paper, soil water movement in layered soilcaused by evaporation from the surface is reported. Three kinds of test columns (the top layer soil only; the top layer soil and sand; the top layer soil, sand and the kuroboku) were placed in chambers which were kept at 20°C, 65% RH or 27°C-32°C, RH free. And the weight of the test columns soil moisture distribution were measured with the lapse of time.
The results obtained are as follows.(1) Specific cumulative evaporation rate curve remains the same without regard to the presence of sublayers.(2) In the initial stage of drying, the average water content of the top layer remains the same without regard to the presence of sublayers, but in the falling rate stage the average water content of the top layer in the test columns having sublayers is larger than that in the columns with no sublayers.(3) Water movement from sand to the top layer begins when the average water content is reduced to 30% and its rate isabout 1/3 of evaporation rate.(4) Soil water in the sand layer moves downward when the average water content of the surface layer is larger than 30%, and moves upward when smaller than 30%.(5) The value of 30% equals the value of the lst critical average moisture content.

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Precipitation is scarce so much enough, it rains at long intervals and it seldom rains heavily during the growing season at OTOSHIBE region. It has been revealed from soil moisture distribution in situ measured by the soil sampling method that (1) the rateof evapo-transpiration is about 2.8mm/ day over the whole moisture range, (2) the field capacity in the top layer is about 50%, (3) the volume of water moved upward from the sand layer to the top layer is about 1/ 3 of evapo-transpiration, (4) this upward movement begins when the average water content in the top layer soil reaches 40%, and (5) water content in sand never decreases to 10% and less.
It is concluded from these characteristics of precipitationand soil water movement that (1) effective rainfall (699mm) is larger than evapo-transpiration (546mm) during the growing season, but in May and June, evapo-transpiration (156mm) exceeds effective rainfall (130mm), and that (2) in April soil moisture depression caused by the use of water is usually supplied by rainfall, but in May and June water content in the soil keeps decreasing and soil moisture moves upward. This soil moisture depression is usually supplied by rainfall in July and August.

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Pumice differs from common soil due to the peculiarity of its pores. The authors studied the properties of pumice with respect to water and obtained following results:
(1) The permeability of pumice layer is smaller than other mineral layers of the same particle size.
(2) Although the water holding capacity of pumice is rather high, the water in the active, semi-active and secondary active pores will change to water which is only present in the crevices between the particles, when small particles of pumice, crystal minerals or rock fragments are mixed in the crevices or pores of pumice particles. It can be inferred from this that the pF-moisture ratio curve of sample of the pumice layer becomes more similar to that of minerals having no pores than that of pure pumice particles.
(3) It is not possilbe to draw out the water present in pumice pore by only the conventional centrifugal method but this type of water can be easily discharged by centrifuge when the pumice particles are turned over after conventional treatment.
(4) When pF-moisture ratio curves of pumice according to particle size are drawn, different curves are obtaineb. If the difference between the moisture ratios at pF 1. 4 and that of pF 3.9 is taken as available water, this becomes the minimum at particle size of 0. 84-0. 42 mm and the quantity becomes larger than this when the particle size is larger or smaller than this.

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As is well known, deflection caused by transverse loading of a plate with an arbitrary external form and a circular hole involves considerably complex problems of boundary values. It is very difficult to obtain exact solutions to these problems, and the author proposes an approximate solution by referring to the Collocation method and a general solution of a differential equation of plates in polar co-ordinate system.
In this paper, arbitrary constants in a general solution of a bi-harmonic differential equation of a plate are determined by exact boundary conditions on the edge of a circular hole and approximate boundary conditions which require exact boundary conditions only at the finite number of points selected on the external edge of the plate. Numerical examples for this analysis method are given, and stresses on the edge of a circular hole in a rectangular plate are calculated and compared with experimental values measured by means of a wire resistance strain gage.

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In my preceding report, a basic equation for calculating contact pressure between a beam and a foundation and vertical, horizontal and shearing stresses in a foundation was derived from a general differential equation of the elastic curve and Boussinesq's stress distribution and strain theory.
In the present paper is given the coefficient of contract pressure in the equation for calculating contact pressure for various cases of loading. If a load is a combination of loads, it is only required to add the values of the coefficient of contact pressure for the respective loads algebraically because the principle of superposition holds in these cases.

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In this paper an analytic method of the freshenning process at continued fresh water lakes is proposed. Each lake has a standard shape, large volume, higher elevation of sill of the outlet gate than the elevation of deepest part of the lake bottom and salt water in lower and, fresh water in upper layer. The hydraulic stability of two layers is very great in ordinary water discharge condition. The method which is deduced in the text was applied to the analysis of freshenning and the terminal salinity of the lake Shiwjiko-Nakaumi. The accunacy of the theory was checked also by experimensal results of hydraulic models for freshenning processes of the lake Shinjiko-Nakaumi.
The actual mechanism of the freshenning processes is very complex, but in this text it has been treated as a macro-phenomenon.

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