Four Years ago, one of the present authors described the climatic divisons of Japan in this journal⁽¹⁾. In determining these divisions, temperature and precipitation were considered independantly of each other. In the course of his studies he observed a marked difference in climate between Kyusyu and the Ryukyu Islands.
Last Spring, the same writer travelled through the last-named islands in order to make detailed observation with these ploblems, the results of which may be summarized as follows:
At Yaku Sima (130° 30'E. 30°20'N.), which lies south of Kyusyu beyond Van Diemen's Strait, a mild climate persists throughout the year. The laterite like soil that lies upon the marine terrace is an indication of the high temperature and great humidity that prevail in the island. The very conspicuous vertical zoning of the climate is clearly recognized in this island; and while in the highest zone subalpine characters predQminate, moderate conditions prevail thrughout the coastal lowlands.
In the Satu-nan Islands the annual march of temperature is very gentle; the maximum being in August. This August-maximum is not restricted to these islands, but is experienced in all the Japanese islands, big and small, although July-maximum is what generally obtains in almost all the other temperate regions of the world. Hence, we cannot very well regard this peculiar condition as being primarily due to the oceanicity of the climate. According to the writer's opinion, it is due to the fact that the July-temperature is lowered by the great amount ob rainfall during the “Bai-u” (a rainy season that lasts front early June until about mid-July). Dr. Okada has also pointed out the remarkable influence exercised by the Bai-u in preventing the rise of July temperature⁽²⁾.
The seasonal variation in the amount of rainfall in these islands is largely influenced by this rainy season and by typhoons, which account for the July and Sepienber maximum, respectively. The annual total rainfall ranges from 2000 to 3000mm, which is no heavier than the rainfall of Southern Kyusyu, Sikoku and the Kii Penninsula, This can be explained by the low position of the observatories in these islands. At the Kosugitani lumbering camp, located on the northeastern slope of Yaku Sima (altitude 750m), the annual precipitation reaches 8080. 8mm (1929-1930). Such a heavy rainfall has rarely been observed in other parts of Japan.
The climatic boundary between Kyusyu and the Ryukyu Islands is considered to lie along the Collet Strait, Van Diemen's Strait is also an important boundary, although of secondary significance.

View full abstract

On the eastern coasts of both Kusaie and of Ponape are preserved the megalithic structures for which these places are noted. The megalithic structures in these two places resemble each other in various ways; the artifacts from them being very similar. The inevitable conclusion is that they are the work of people of the same culture. Stone structures are found all over Polynesia, especially in the central and northern parts of the group. They mark the centre of the social actvity of the islanders and also the sacred precincts.
The ruins found in Kusaie and Ponape resemble the Polynesian stone structures, suggesting some cultural kinship. Many cultural elements of the Eastern Caroline islanders resemble those of the Polynesians, and the megalithic structures are probably examples of it. It is to be noted., however, that, the stone ruins of the eastern Carolines .are either situated near the sea or rise from it. In these respects they differ from the Polynesian. Some artifacts discovered there are not of Polynesian type. These are significant facts in the problems concerning the relations of the two types.

View full abstract