It is well known that a gravitational wave caused by a tidal change propagates upstream with a velocity of √gH (H: depth). According to a field observation conducted by the author on the Teshio River, the surface level of water at the distance of 5 km from the mouth changes periodically with the same phase of the tidal change. This can be explained by a fact that the distance of 5 km is too short for the wave to travel from the mouth to the station with a velocity of √gH. Velocity of surface flow, however, is observed to change with a phase difference of about 3 hours at the upper station and at a station near the mouth. This phenomenon can be analyzed by a theory of internal wave. Except the period of flood, the Teshio River has a stratified layer of fresh water and salt water which is called as a salt-wedge. An internal wave is generated at the interface by any disturbance as wind, atmospheric depression, tidal change, etc., and is propagated with a velocity of about √ (1-γ)gH₁+U₁ (γ: density-ratio of fresh water to salt water, U₁: vertically mean velocity of a surface-flow, H1: thickness of a fresh layer). Then, by computing a travelling time of the internal wave, the phase-difference of the surface-velocity between the two stations can be estimated as about 3 hours.

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1. Among the drift bottles released in the North Pacific Ocean since 1932 18 bottles were cast ashore on the western coast of North America and 4 bottles were found on the sea near the continent.
The percentage of the number of the bottles found to those released in 1958 and 1959 was 2%.
2. Among the drift bottles released in the area C 4 bottles were found and 2 were picked up near the Hawaii island. On the other hand it is reported by HOLLISTER (1958) that among the bottles released near the fixed point “PAPA” 816 bottles were found, but was only one cast on the Hawaii island.
3. The surface velocity of the subpolar current between 150° N and 150° W is about 4 nautical miles a day, while the mean velocity of drift of 17 bottles found on the western coast of North America reaches about 4.7 nautical miles a day and is larger by 20% than the surface velocity of the subpolar current. The difference depends chiefly on the drift effect of wind and the indirect one-drift current by wind.
4. The bottles released in the coastal region of the Oyashio, in the offshore region of it, in the mixing region between the Oyashio and Kuroshio, and in the Kuroshio region were found on the northern coast of Japan proper, on the coasts of Alaska and Canada, on the coast of U. S. A. from 40° to 50° N, and on the sea south of 40° N, respectively.
This shows that the water masses in which the bottles were released decide their destinations.
5. Among the bottles released in Japan Sea most parts were found on the coast of the Japan Islands 2 bottles were cast on the coasts of Alaska and Washington State, U. S. A., and on the Pacific (25° N, 175° W).
6. From the above mentioned it is imaginable that the northern limit of the surface water of the Oyashio flowing southwards in spring and summer is near the strait of Kita-urupu.

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In case of disposing radioactive wastes into the sea the container has to reach the deep-sea floor safely and exactly and to remain in safe conditions without being destroyed for an extremely long time. In order to attain this purpose the container must remain at a depth of 2, 000 m, and accordingly it must withstand the hydraulic pressure and other oceanic conditions at this depth. For the purpose of acquiring basic data for determining the standard of economical and safe container we have carried out the investigations on form, strength, corrosion resistance, etc. of the container.
Above all things a cylindrical container made of concrete and covered with thin metal plates may be considered to be suitable as economical and practical one for disposing radioactive wastes. Consequently in the present studies we constructed containers of cylindrical form like an oil drum, which have three different sizes and are made of mortar; we carried out collapse tests. Among the results of the tests the value of wall thickness / mean radius (t/r) against collapse pressure of these three kinds of containers are similar to each other. The value of t/r of the cylindrical con tainer corresponding to the critical collapse pressure of 200 kg/cm² is 0.25. This shows that the cylindrical part of container will be able to be designed dependent only upon the value of t/r, if the size of the cylinder be not so extremely different from that of the body to be tested. From. the results of similar experiments on the end-plate of the container it became clear that the container will be able to withstand the hydraulic pressure of 200 kg/cm², if the end-plate thickness/ inner diameter of the cylinder (t/d) be 0.26.
Various kinds of metallic material may be considered to be suitable as metal used in the cover of the container, however, the steel plates of drums are not only economical in case of using large numbers at a time, but also now used as containers for disposing radioactive wastes.
We constructed the apparatus capable of reproducing oceanic conditions such as temperature of sea water, dissolved oxygen and current velocity within the laboratory and using this apparatus we carried out the corrosion test of the steel plates of drum in an artificial sea water. From the test we obtained the result that the weight loss by corrosion during 168 days was about 15× 10^-3 g/cm² in conditions, where the temperature of the artificial sea water was 2°C, the dissolved oxygen was 2.65 ml/l and the current velocity was 1.5 cm/sec.
It is found that not only the dissolved oxygen is a primary factor of the corrosion of steel plate in the artificial sea water, but also the current velocity will play an important role in the corrosion, even if it be very slow.

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As the Niigata Harbor basin facing to the Japan Sea is situated on the estuary of the River Shinano, the entrance is buried by sands from the upstream of the river and from the seaside. To determine which directions the sands mainly come from, the glass sands (a mean size of 0.1mm) containing ⁶⁰Co were released on the estuary bottoms twice in 1961.
At the first survey, in August a total activity of 140 mc was released at five points selected in this area, and the movement of labelled sands was followed by a GM-counter until the end of October of the same year. The surveys showed that the sands moved relatively slowly in the summer season, some of the labelled sands was found up to 100 m from the injection point within the three months at the most dispersed area.
At the second time, in November, a total activity of 500 mc of ⁶⁰Co was released in the similar manner, but at three points, instead of the previous five. The subsequent movement of sands was measured in April of the following year, because we intended to know the movement of sands by storms during the winter. As a result of this survey, it was found that the activity due to nuclear detonations in the autumn of the previous year prevented the accurate measurement by this counter. Because of this activity, we had to perform nuclide analysis of samples of sands taken from the bottom using a pulse height analyser. By this analysis we confirmed that the main constituent (emitting gamma rays) was ⁹⁵Zr-⁹⁵Nb, followed by ¹⁰³Ru and ¹⁴² Ce-¹⁴² Pr.
After above survey, we investigated the movement of littoral sands under sea water using ⁴⁶Sc- glass as tracer at the west coast of Niigata for two months from April to May 1962. This coast is one of the most well known place in Japan for the retrogression of the coast line. We carried out this survey to determine the main direction of transport of the sand material in the sea area within 500 m from the coast line and intended to get the datum for a measure of protection.
By this survey, the trajectories of radioactive sands could be exactly determined. Then, the relation between the trajectory and oceanographical data (wave, current, etc.) was studied. The results of this study suggested that the sands in this area were as a whole transported westward along the coast line through the year.

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When we consider the albedo of the sea surface, the upward light in the sea water, or the emergent light vertically upward from the sea is to be considered in relation to the incident light into the sea. This consideration may also be indispensable not only for the theoretical discussions on the water colour and the transparency, but also for the practical problem such as the application to fishing conditions.
The ratio of the emergent light to the incident light has been investigated theoretically and experimentally by several authors (TAKENOUCHI, VERCELLI). These results showed that this ratio takes different values of a few to several percents. This may be considered due to be dependent on many factors as follows: the sun's altitude, the meteorological conditions such as the cloudiness, the fog and the turbidity of the atmosphere, and also oceanographical conditions such as the state of the sea surface, the turbidity of the sea water, and the stratification of layers in the sea, and so on. Of course, the wave length of the short wave radiation is to be considered, and thus, the problem is too complicated to be solved in a simple manner. However, the purpose of this paper is to give some approaches to the solution of this problem.
The emergent light from the sea is to be considered when we deal with the albedo of radiation over the sea surface. On the basis of some observations conducted by the author, this problem was studied with the theoretical consideration in this paper. The result shows that the ratio of the upward light to the downward light is about 2% in the oceanic water, while it takes much larger values, ranging between 2%-10% in the coastal water, and this may be supposed to be due to the quality of the suspended matter in the sea water.

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A new species of Euphausiacea, Thysanoëssa inspinata, from the North Pacific is described. Thysanoëssa inspinata has been included in the part of the spineless form of Thysanoessa longipes, but it is divided from T. longipes in following points.
1) Thysanoëssa inspinata has the lateral denticle in the far posterior position in the lower margin of the carapace.
2) The terminal process and proximal process of the male copulatory organ are nearly the same size and shorter in T. inspinata
. 3) A specimen of Thysanoëssa longipes lacking abdominal spines which is considered to be the real spineless form is found, which has the different taxonomical character from Thysanoëssa inspinata. Other taxonomical points and ecological features of Thysanoëssa inspinata are also discussed.

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