the warm ocean current that strikes Japan from the south, and precipitates it over almost the whole of Korea; so that there is a distinct "rainy season" during most of the months of July and August. This rainy season also has played an important part in determining Korean history. Unfortunately for navigation, the western side of the peninsula, where most of the good harbours are found, is visited by very high tides, and the rapid currents which sweep among the islands make this the most dangerous portion of the Yellow Sea. On the eastern coast a cold current flows down from the north, and makes both summer and winter cooler than on the western side.
Though the surface of Korea is essentially mountainous, it resembles Japan very little, for the peninsula lies outside the line of volcanoes which are so characteristic of the island empire. Many of the Korean mountains are evidently extinct volcanoes, especially White Head Mountain, in whose extinct crater now lies a lake. Nor does Korea suffer at all from earthquakes. The only remnants of volcanic action that survive are the occasional hot springs. The peninsula is built for the most part on a granite foundation, and the bare hill-tops, which appear everywhere, and are such an unwelcome contrast to the foliage-smothered hills of Japan, are due to the disintegration of the granite and the erosion of the water during the rainy season. But there is much besides granite in Korea. There are large sections where slate prevails, and it is in these sections that the coal deposits are found, both anthracite and bituminous. It is affirmed by the Korean people that gold is found in every one of the three hundred and sixty-five prefectures of the country. This doubtless is an exaggeration, but it is near enough the truth to indicate that Korea is essentially a granite formation, for gold is found, of course, only in connection with such formation. Remarkably beautiful sandstones, marbles and other building stones are met with among the mountains; and one town in the south is celebrated for its production of rock crystal, which is used extensively in making spectacle lenses.
