The measurements of the transmission of light through the following three different kinds of artificial fog and smoke were made in the visible range of 4300 Å to 7500 Å and in the infra-red range of 7500 Å to 9500 Å. The same apparatus as in the previous experiments was used. The measurements were done by using a glass-spectrograph and a wooden cloud chamber which is 400cm long, 30cm wide. and 30cm high, The three kinds of the fog and smoke are: (1) Fog condensed from the aqueous vapour of low pressure was introduced into the cloud chamber. (2) Fog was made directly from water by using a sprayer. (3) Smoke of tobacco was introduced into the chamber. As to the artificial fog produced from the aqueous vapour of low pressure, a maximum of transmission coefficient was found at about 4700 Å and a minimum around 5050 Å. As the wave-length increased, the transmission coefficient also seemed to increase, but some decrease was found at 8100 Å to 9500 Å. As to the fog produced with a sprayer, a maximum was also found at 4700 Å and its value decreased gradually as the wave-length increased. A small increase was found at 7500 Å to 8100 Å, but a gradual decrease was again noticed at 8100 Å to 9500 Å. As to the smoke, a maximum of transmission coefficient was found at about 4800 Å and a minimum at about 5200 Å. From this minimum point, the coefficient increased gradually as the wave-length increased through 6500, 7500, 8100, to 9500 Å. The sizes of the fog and smoke particles used in this experiment were measured, except that of the aqueous vapour. From the results obtained by the previous experiments, it was found that Rayleigh's formula of scattering is not satisfied, and it might be pointed out that King's formula is not applicable to the scattering of light by water particles produced with sprayers.
In order to avoid the defect of Colding's empirical formula for calculating the elevation of the sea level caused by winds, H. Arakawa and M. Yoshitake discussed the effect of the stationary wind upon the sea level based on an interesting concept. In the present paper, the same method was adopted by the author. Thus, it was shown that the slope of the sea level close to the coast becomes remarkably steep, and that the relation between the elevation of the sea level and the fetch depends upon the topographical features of the sea-bottom. For example, in case of a uniform depth, the elevation is proportional to the fetch itself, while in case of a parabolic depth curve, the elevation is proportional to the square root of the fetch. Moreover, it was shown that if the depth is shallower, the wind-gradient is larger, and if the slope of the sea-bottom is smaller, the elevation becomes higher. Even when the wind does not blow in the neighbourhood of the coast, it can be proved that a considerable amount of upheaval occurs along the shore as long as the wind blows off the shore. In this region of calm, the upheaval caused by the wind off the shore is uniform if the wind is stationary, and not uniform if the wind is not stationary. In case of non-stationary wind, we can discuss the elevation by the so-called Mass Transport Theory. According to it, we can get the solution for the elevation comparatively easily, even if we can not solve the motion of the sea water explicitly, since we have only to consider the equation of elevation. In this paper, we have discussed the case of the wind velocity increasing exponentially with the time. The equation to be solved is (41), and the boundary conditions are (43), (44) and (45), of which two are independent. Generally speaking, the sea level in a canal is not reverse-symmetric to the central line of the canal. The sufficient condition of reverse-symmetry is that the distribution of wind velocity is symmetric to the central line with constant wind direction. When the gradient of the wind velocity is positive, the elevation on the lee side is larger than the depression on the windward side, and vice versa. However, owing to the rotation of the earth, the elevation on the lee side is not always positive. A discussion was also made on the effect of the fetch, depth, wind-gradient and latitude of the place on the elevation of the surfaces of a canal and a semi-infinite ocean. We obtained the solution for the case of the line of discontinuity of wind lying on the sea, and it was concluded that the slope of the sea level also becomes discontinuous along the line of the discontinuity of wind.
We observe two jet streams in the upper westerlies during the Baiu season, which are situated along the 140°E meridian at 35°N and 60°N, respectively. These two jet streams join in a gingle stream over the Bering Sea. The southern branch of the jet stream is always observed over Japan during the Baiu season. When cut-off low appears near Japan in the end of the Baiu, the southern branch of the jet stream disappears suddenly. In the higher latitudes, however, the jet stream stays at the some latitude. When the jet stream over Japan disappears, the field of the confluence of jet streams will also give way, and then the Baiu will be over. That is to say, the cut-off low disturbs greatly the upper westerlies near. Japan, and accelerates the northward advancement of the warm air. Then the summer comes to Japan. According to the conclusion derived from the above discussion, we know that the transition of season (from the Baiu to summer) will be very sudden.
§ 1 General equations of motion parallel and normal to the characteristic lines. § 2 The tangential and normal equations of motion in the system of natural coordinates. § 3 Equations of motion parallel and normal to the isobars.