ANNOTATIONS AND ADDITIONS. 77 



directions of mountains and of rivers. The knowledge and use of 

 the " South pointing" of the magnetic needle twelve centuries before 

 our era, has given to the orographic and hydrographic descriptions 

 of countries by the Chinese, a great superiority over the descriptions 

 of the same kind which Greek or Roman writers have bequeathed 

 to us, and which are besides extremely few. The acute and saga- 

 cious Strabo was alike imperfectly acquainted with the direction of 

 the Pyrenees, and with those of the Alps and of the Apennines. 

 (Compare Strabo, lib. ii. pp. 71 and 128; lib. iii. p. 137; lib. iv. p. 

 199 and 202; lib. v. p. 211, Casaub.) 



To the lowlands belong almost the whole of Northern Asia to the 

 north-west of the volcanic chain of the Thian-schan; the Steppes to 

 the north of the Altai and of the Sayan chain ; the countries which 

 extend from the mountains of Bolor, or Bulyt-Tagh, (" cloud moun- 

 tains" in the Uigurian dialect,) which follow a north and south 

 direction, and from the upper Oxus, (whose sources were found by 

 the Buddhistic pilgrims Hiuen-thsang and Song-yun in 518 and 

 629, by Marco Polo in 1277, and by Lieutenant Wood in 1838, in 

 the Pamer Lake, Sir-i-kol, Lake Victoria,) towards the Caspian; 

 and from Tenghir or the Balkhash Lake through the Kirghis 

 Steppe, towards the sea of Aral and the southern extremity of the 

 Ural mountains. As compared with high plains of 6000 to 10,000 

 feet above the level of the sea, it may be well permitted to use the 

 expressions of "lowlands" for flats of little more than 200 to 1200 

 feet of elevation. The lowest of the last two numbers corresponds 

 nearly to the altitude of the town of Mannheim, and the highest 

 to that of Geneva and Tubingen. If the word plateau, so often 

 misemployed in modern works on geography, is to have its use ex- 

 tended to elevations which hardly present any sensible difference in 

 climate and vegetation, the indefiniteness of the expressions " high- 

 lands and lowlands," which are only relative terms, will deprive 

 physical geography of the means of expressing the idea of the con- 

 nection between elevation and climate, between the profile or relief 

 of the ground and the decrease of temperature. When I found 

 myself in Chinese Bzungarei, between the boundary of Siberia and 

 Lake Dsaisang, at an equal distance from the Icy Sea and from the 

 mouth of the Ganges, I might well, consider myself in Central Asia. 



