The vast mountain mass extending from Asia Minor to the Pacific tlso harms Asia by almost completely separating the north from the ,outh. Mountainous projections in Persia and Indo-China divide the ,outhern section into three isolated regions centering in Mesopotamia, he Indo-Gangetic plain, and the plains of China. Today no railroad rosses the mountains from north to south, or penetrates from one of he three southern regions to the other. The only place where a rail oad can easily cross from north to south is eastern Persia and western Ithanistan. This route where railroads from India and Asiatic tussia now almost meet corresponds quite closely with the gap in the :uropean mountains along the Rhone Valley. But in Asia nearly wo thousand miles of desert separate the productive regions of the 'aucasus and the Indus delta, while the European railway everywhere ins through a land of dense population and wonderful possibilities. reat cities like Lyons and Marseilles in Europe correspond to little ud towns like Mery and Herat in Asia.
Railway connection between the east and the west of Asia is almost limited as between the north and south. Only in the far northeast ;es the. Siberian railway cross the northern wing of the great central ountains. There, too, vast barren tracts must be traversed. For a ousand miles between the fairly prosperous Irkutsk region and the rtile part of Manchuria, the Trans-Baikal region is so cold that there almost no population. Chita, with its 80,000 people and its log huts, icupies a position on this line comparable to that of stately Vienna .rich guards the passage of the mountains on a similar line in Europe. The plains of Asia, although of vast size, are for the most part much }is desirable than those of Europe. In the huge Siberian plain the Ob, Yenesei, and Lena river systems would provide fine inland water ways, were it not that their northward direction largely destroys their value, while the low temperature greatly restricts the population. Th@ southern plains in Arabia and India' are much handicapped by being either too dry or too warm.
The other main features of the relief of Asia are the plains of th1 eastern coast from Manchuria to Indo-China, and the mountainoul island fringe from Sakhalin and Japan to Sumatra and Ceylon. Th4 plains, though fertile, are small compared with those of Europe, th® United States and South America, and the islands are extremely rugged' In general the relief of Asia hampers human progress because it dividel the continent into a number of diverse sections instead of drawing large part toward a center as in Europe, and because the most favorab relief is located where the climate is unfavorable.
The Great Climatic Extremes of size, shape, positioni and relief of Asia all combine to produce climatic extremes and con trasts. Fully half of the continent has a winter climate colder that
that of anything except the mere northern fringe of the inhabited partg of North America. This is a serious deterrent not only to agricultum, but to human health and efficiency. The summers, however, even in this northern half are warm. Near the Arctic Circle the maximum tem perature is sometimes F. In Yakutsk, in latitude N., the July average is F., or as high as on the northwestern coast of Spain, farther south. The period of active plant growth, however, lasts on* three months instead of eight. Farther south, the summer temperatu* is usually extreme. At Tashkend, for example, in the latitude of Neg. York, it averages over 80° in July, and remains above 74° for thme months. Aside from limited areas at high levels in relatively low lati tudes, almost all parts of Asia suffer at some season from prolonged and harmful extremes of cold or heat.
Northern Asia gets some rain from local showers in summer and some from cyclonic storms. North of latitude the coolness of the summers causes a small rainfall to suffice for forests and agriculture. Asia, however, has relatively few cyclonic storms like those of thee United States and Europe. In fact, Japan is the only Asiatic region that can compare with Europe in number of storms and hence in the stimu-1 lating quality of its changes of temperature, humidity, and sunshine+ In the latitudes which in Europe are most favorable, that is, from about, to the summers are so warm and dry that the region east the Ural river and north of the Sea of Aral and Lake Balkash forms steppe or grassland, good for horses, sheep, and camels, but generally too dry for crops.
Farther south a vast desert belt, 50 per cent larger than Europe, extends from Aden in Arabia and Aleppo in Syria almost to Peking in China and Harbin in Manchuria. Certain areas like Russian Turkestan have well watered and fertile valleys that support a fairly dense popu lation, hut they form a small percentage of the whole. This desert belt, extending across Asia from the Red Sea almost to the Pacific Ocean, intensifies the effect of the mountains in separating northern and southern Asia. It limits the natural resources by discouraging vegetation; moreover, the extreme dryness, the monotony from day to day, and the enforced nomadic life of many of the people retard the development of even the scanty resources that are available. The distress and wars arising from periodic dryness within this belt are generally supposed to be among the chief reasons why the people of central Asia have migrated outward so often.