OF CENTRAL AND EASTERN ASIA. 191 



fact, that it is represented as traversed by chains of mountains, 

 a feature which the latter region does not present. This is a 

 very important difficulty, and will require some considera- 

 tion. 



It is not easy for us to ascertain the degree of correctness 

 with which Ptolemy has described Great Thibet, from our be- 

 ing ourselves almost totally ignorant of that region. We can 

 only form a favourable presumption, from the accuracy with 

 which he has delineated those conterminous regions, with 

 which we are better acquainted *. But it is certain, that on ap- 

 proaching the confines of Serica, that twilight of knowledge 

 must have begun, which always precedes its total extinction. 

 A peculiar source of obscurity there arose. It was the deci- 

 ded policy of that country, as it has always been of modern 

 China, to shut the empire, with the most jealous care, against 

 the entrance of foreigners. Commerce was permitted only at 

 one single point, and it was carried on with the least possible 

 communication ; nay, according to an often repeated assertion, 

 without the parties even seeing each other. It was impossible, 

 therefore, that the ancient writers could possess authentic de- 

 tails relative to the interior of Serica. But an infirmity beset 

 Ptolemy, which continued always to prevail among geogra- 

 phers, till the great reform effected by D'Anville. It was 

 conceived discreditable, that any district within the limits of 



the 



* I shall mention, however, the following names, in which the resemblance is 

 somewhat rude ; but allowance must be made for the passage through Grecian 

 organs ; and the positions correspond very precisely. Chauranei (juxta Emodos 

 Montes), Mount Chumularee. Achassa, — Lassa. Chatcc (Khalai, Gr.) Khata, 

 on the Upper Barraimpooter. (See M. Vansittarts Account of Assam. Asi- 

 at. Research, vol. vii. Damna, — Daum. Otlorocoras, — Uttarcul or Ootrecole. 

 This last must be understood in connection with the observations which follow- 

 in the text. 



