salt basin and are there absorbed. Only the largest, whose number the Chinese estimate at sixty, unite with the Tarim, a river 1,150 miles long, and therefore in length between the Rhine and Danube, but far surpassing both in the massiveness of surrounding mountains, just as it exceeds the Danube in the extent of its basin. Its tributaries form along the foot of the mountains a number of fruitful oases, and these by means of artificial irrigation have been converted into flourishing, cultivated states, and have played an important part in the history of these regions.”[122] Col. Prejevalsky’s explorations in this totally unknown country have brought out a multitude of facts pregnant with interest both for historical and geographical study. Among the most important results of his discoveries is the location of Lob more than a degree to the south of its position on Chinese maps, and a consequent bend of the Tarim from its due eastern course before it reaches its outlet. This lake, consisting of two sheets of water, the Kara-buran and Kara-kurchin (or Chon-kul), lies on the edge of the desert, in an uninhabited region, and surrounded by great swamps, which extend also northwest along the Tarim to its junction with the Kaidu. It is shallow, overgrown with weeds, and is for the most part a morass, the water being fresh, despite the salt marshes in the vicinity. The people living near it speak a language most like that of Khoten; they are Moslems. Lake Lob is elliptical, 90 to 100 versts long and 20 wide, 2,200 feet above the sea. Enormous flocks of birds come from Khoten on the south-west, as they go north, and make Lob-nor their stopping-place. The desert in this region is poor and desolate in the extreme. Its southern side is formed by the Altyn-tag range, a spur of the Kwănlun Mountains that rises about 14,000 feet in a sheer wall. Wild camels are found in its ravines, whose sight, hearing, and smell are marvellously acute. No other river basins of any size are found within the Circuit, except a large tributary called the Kaidu, which, draining a parallel valley north of Lob-nor, two hundred miles long, runs into a lake nearly as large, called Bostang-nor, from which an outlet on the south continues it into the Tarim, about eighty miles from its mouth. The tributaries of this river are represented as much more serviceable for agricultural purposes than the main trunk is for navigation. The plain through which the Tarim flows is about two hundred miles broad and not far from nine hundred miles long, most of it unfit for cultivation or pasturage. The desert extends considerably west of the two lakes. The climate of this region is exceedingly dry, and its barrenness is owing, apparently, more to the want of moisture than to the nature of the soil. The western parts are colder than those toward Kansuh, the river being passable on ice at Yarkand, in lat. 38°, for three months, while frost is hardly known at Hami, in lat. 43°.