58 YIETTS OF NATURE. 



between the boundaries of Siberia and Lake Saysan (Dsai- 

 sang), at an equal distance from the Icy Sea and the mouth of 

 the Ganges, I might assuredly consider myself to be in Central 

 Asia. The barometer, however, soon showed me that the 

 elevation of the plains watered by the Upper Irtysch between 

 Ustkamenogorsk and the Chinese Dzungarian post of Choni- 

 mailachu (the sheep- bleating) was scarcely as much as from 

 850 to 1170 feet. Pansners earlier barometric determinations 

 of height, which were first made known after my expedition, 

 have been confirmed by my own observations. Both afford a 

 refutation of the hypotheses of Chappe D'Auteroche (based on 

 calculations of the fall of rivers) regarding the elevated position 

 of the shores of the Irtysch, in Southern Siberia. Even 

 further eastward, the Lake of Baikal is only 1420 feet above 

 the level of the sea. 



In order to associate the idea of the relation between low- 

 lands and highlands, and of the successive gradations in the 

 elevation of the soil, with actual data based on accurate mea- 

 surements, I subjoin a table, in which the heights of the ele- 

 vated plains of Europe, Africa, and America are given in an 

 ascending scale. With these numbers we may then further 

 compare all that has as yet been made known regarding the 

 mean height of the Asiatic plains, or true lowlands. 



Plateau of Auvergne 

 „ of Bavaria . 

 „ of Castille . 

 „ of Mysore . 

 „ of Caracas . 

 „ of Popayan . 



of the vicinity of the Lake of Tzana, 

 in Abyssinia .... 

 „ of the Orange River (in South Africa") 

 „ of Axum (in Abyssinia) 

 „ of Mexico ..... 

 „ of Quito ..... 

 ., of the Province de los Pastos . 

 „ of the vicinity of the Lake of Titicaca 



» 



No portion of the so-called Desert of Gobi, which con- 

 sists in part of fine pasture lands, has been so thoroughly 

 investigated in relation to its differences of elevations as the 

 zone which extends over an area of nearly 600 miles, be- 



