As the appropriate level for the balloon bombs 10-12 km level has been selected, for the level is the barotropic surface with maximum westerly currents. During the winter 1944-1945, many balloons were sent to United States from Japan, for this period is characterized by heavy baroclinicy in the middle latitudes and hence the greatest strength of the westerlies is found in winter. Two or three days will be enough to send balloons through the upper troposphere, if the conditions are favourable.
The ratio of sulphate to chlorine is always constant (viz. 0.13648) in ordinary pelagic water. But the writer found in several bays (Heda Bay, Mera Bay, Arari Bay, Uchiura Bay, Nakagi Inlet, Nagatsuro Inlet etc.) in Izu Peninsula the fact that the ratio (SO4″ : Cl′) deviated from the standard value and showed anomalies, because sulphate being consumed owing to the activity of sulphate-reducing bacteria existed in the water. If ventilation of sea water were free, anomaly could never occur. The stagnation of a bay can happen on account of geomorphological cause, such as existence of a submarine threshold in front of a bay or enclosed topography underneath the surf ace water. If we should be able to gain certain relation between the anomaly and inorganic sulphur contained in bottom material, the study on sedimentary rock would be brought to light, so far as sedimentational environment (anaerobic condition) is concerned.
Fifty-two miles to the north-west of the port of Inchon lies the small island of So-nYonpyong-do. Evenly distributed on the summit of this island's hill is to be found an are deposit of the eutectic mixture of ilmenite and vanadium-bearing magnetite occurring in bedded form and as a product of magmatic differentiation in the spotted pyroxenite derived from gabbro. This are deposit has twenty meters in thickness and spreads over an area of twenty-six thousand square meters. The are reserve is estimated at 2, 300, 000 metric tons. The typical are runs 50% in iron, 20% in titanium dioxide and 0.24% in vanadium. This are deposit ranks highest as a titanium deposit in Korea. By either oil flotation or magnetic separation, the are could be separated into ilmenite containing 47% TiO2 and vanadium-bearing magnetite containing 65% Fe. Great hopes are placed on the development of this are body, as Japan is poor in titanium resources.