The possible thermal processes near the earth's crust are studied with special regard to a process presented by Prof. Matuzawa in his recent paper titled “Feldtheorie der Erdbeben.”, in which a solid-liquid transformation plays an important part. Before the discussion of this particular process, the present writer gives the necessary condition for the stationary conversion of thermal energy into mechanical energy inside a system of material through which a stationary heat flow exists. It is shown that this condition is satisfied near the crust in two and only two cases, of which in the first a mass flow exists in the system, and in the second the relation α=β+1 exists between the number α of phases and the number β of components of the system. The first case corresponds to the convection theories of the cause of earthquake and the second corresponds to the phase transformation theories, to which Prof. Matsuzawa's theory belongs. The necessary heat supply for a great earthquake was shown quantitatively in his paper. It is emphasized that such an amount of heat energy can only be supplied by the convection current under the crust. And the writer obtains by the aid of experimental and theoretical laws of heat transfer through a free convection the relation between the scale of convection and the viscosity of material under the crust required for the effective operation of Matuzawa's process. If such a convection has a scale of 100km, the viscosity of material must be 10¹⁷ poise, its maximum current velocity is estimated to be 50m/year and it exerts a tangential stress of the order of 10⁷ dyne/cm² along the lower surface of the crust.
Those results that the subcrustal current which is believed to account for the mountain formation may accompany Matuzawa's process, that Matuzawa's process which amply explains the cause of a great earthquake needs the heat energy supplied by the subcrustal current which also exerts a considerable stress, and that the possible stationary conversion of the thermal energy into mechanical energy must by confined to the above two cases, may lead us to the conclusion that those two processes combined play a very important part in the physical phenomena near the earth's crust.

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We determined singular points on the four Riemann planes in our previous paper as the first stage for solving our subject. In this paper, assuming a dilatational point source, we get displacements at various epicentral distances.
The main results obtained in this paper compared with the results in semi-infinite solid obtained by T. Sakai are as follows:
(1) The waves, which are propagated along the interface, are P-wave in solid, Rayleigh wave whose velocity is slightly smaller than that of sound in water and compressional wave in water and S-wave in solid.
(2) P-wave is almost similar to the same wave in the case of semi-infinite solid but from the point of view of the form of the equation S-wave in the case of semi-infinite solid corresponds to compressional wave in water rather than S-wave in our case.
(3) At a large epicentral distance on the boundary, the maximum values of the vertical components of displacements are generally smaller than those of the horizontal except S-wave.

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A new device for obtaining precise revolutions is described. Basic principles of the device are as follows. One of the higher harmonics having the desired frequency contained in the square wave given by electrical contacts of a chronometer is picked up by a “mechanical tuned filter” of high resolving power and this filterd wave is supplied to a phonic motor or synchronous motor. The revolution of the motor thus obtained is as precise in rate as the standard chronometer. In the previous experiments, 1c./s. square wave was divided into 20c./s. square wave by the similar method and a precise revolution of the phonic motor was obtained. In the present experiments, 20c./s. square wave was divided further by a similar filter into 60c./s. A. C. of which the accuracy of the frequency is as high as that of the standard chronometer. Some new device for measuring a period of gravity pendulums etc. on this principle is briefly mentioned.

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