Page:Popular Science Monthly Volume 21.djvu/542

 the rocky walls bearing in their clefts the eternal ice which glitters and sparkles in the clear sunlight like a gigantic diamond. Similar in structure, but made more imposing by the fact that the steep precipices are planted directly on the untilled plain of the Tarim basin, without any notable intermediate slopes, rises the extreme chain of the Kuenlun system as the northern boundary of the Thibetan highland. The western boundary is formed by the chain of the Karakorum, with its Triassic and Carboniferous formations, and the furrowed Pamir plain; and the eastern boundary by the curved declivities of the Himalaya system itself, descending with a somewhat more gentle slope toward China. Penetrated by numerous streams which, as a whole, maintain a north and south course, the intervening mountain-regions present formidable impediments to communication. The traveler is overlooked from all directions by icy mountain-peaks that rise to an average height of at least twenty thousand feet. The high table-land itself presents a sad aspect. The enormous height and the climatal conditions dependent upon it restrict vegetation within a narrow limit. No trees are found there, or cultivated fields, no flowers or fruits; and the green spots on which the stunted lavender maintains a precarious existence may be counted among the broad basins filled with gravel and pebbles. The winds bring no moisture. The sparse snow-falls of the year are not enough to impart productivity to the earth, and the plateau is nearly destitute of animal and plant life.

The Thibetan settlements are almost entirely situated in the valleys of the larger rivers, which the relatively lower situation, the higher degree of moisture in the atmosphere, and the possibility of irrigation enable the inhabitants to bring to a measure of tillability. A certain degree of fertility of the soil of the capital can not be denied. Two principal rivers have their sources at a nodal point in the Himalayas, whence they cross the more southern country and India from left to right. They are the Indus in the west and the Sampo in the east. The course of the Indus is well known and marked, but all that has been ascertained of the Sampo is that it maintains a nearly easterly course to southeast of Lassa, after which it is still in doubt whether it becomes the Brahmapootra or the Irrawaddy.

The climate is very severe. The temperature in winter often falls to from 13° to 22° below zero; all the rivers and lakes are covered with ice as early as November, and even in April the sun has not acquired vivifying force enough to melt their crystal surfaces.

No European is allowed to pass over the southern boundary of this country. The East Indian Government has made several attempts to gather information about it, but has been baffled. Colonel Montgomery, a few years ago, conceived the idea of instructing young Indian Buddhists in geography, and sending them to Thibet in the guise of natives. Carrying only indispensable instruments with them, they have been exploring the plateau since 1865, and have till recently