courses, which only contain water after heavy rains, and even then for not more than a few hours. Along these water courses the inhabitants dig wells to supply themselves with water. No running streams are met with the whole way from the River Tola to the borders of China Proper, i.e. for about 600 miles; the rains in summer forming temporary lakes in the loamy hollows which soon dry up during the severe heat.
The soil of the Gobi Proper is composed of coarse reddish gravel and small pebbles interspersed with different stones such as occasional agates. Drifts of yellow shifting sand also occur, although of a less formidable character than those in the southern part of the desert.
Vegetation finds no sustenance here, and the Gobi produces even grass but scantily. Completely barren spots are certainly rare along the Kalgan road, but such grass as grows is less than a foot high, and hardly conceals the reddish-grey surface; only in those places where the gravel is replaced by clay, or in the hollows where the summer moisture is longer retained, a kind of grass called by the Mongols Dirisun {Lasiagrostis splendens), grows in clumps four to five feet high, and as tough as wire. Here and there too some solitary little flower finds an asylum, or if the soil is saline the budarhana (Kalidium gracile), the favourite food of camels, may be seen. Everywhere else the wild onion, scrub wormwood, and a few other kinds of Compositæ and Gramineæ, are the prevailing vegetation of the desert. Of trees and
