The third great division of the colonial part of the Chinese empire, that of TIBET, is less known than Ílí, though its area is hardly less extensive. It constitutes the most southern of the three great table lands of Central Asia, and is surrounded with high mountains which separate it from all the contiguous regions. The word Tibet or Tubet is unknown among the inhabitants as the name of their country; it is a corruption by the Mongols of _Tu po_,[133] the country of the Tu, a race which overran it in the sixth century; Turner gives another name, _Pue-koa-chim_, signifying the ‘snowy country of the north,’ doubtless a local or ancient term. The general appellation by the people is _Pot_ or _Bod_, or _Bod yul_--“the land of Bod.”[134] It is roughly bounded northeast by Koko-nor; east by Sz’chuen and Yunnan; south by Assam, Butan, Nípal, and Gurhwal; west by Cashmere; and north by the unknown ranges of the Kwănlun Mountains. The southern frontier curves considerably in its course, but is not less than 1,500 miles from the western extremity of Nípal to the province of Yunnan; the northern border is about 1,300 miles; the western frontiers cannot be accurately defined, and depend more upon the possession of the passes through which trade is carried on than any political separation. Beltistan, Little Tibet, and Ladak, although included in its limits on Chinese maps, have too little subjection or connection with the court of Peking, to be reckoned among its dependencies. ~NATURAL FEATURES OF TIBET.~