238 Baron Humboldt on the Mountain-Chains and 



of mountains, than the table-lands between the first, second, and 

 third systems of mountains. Consequently, Tibet and Kachi 

 cannot properly be compared, in respect to their geognostic 

 construction, with the elevated longitudinal valleys*, situated 

 between the chain of the eastern and western Andes, for ex- 

 ample, with the table-land which encloses the lake of Titicaca, 

 a correct observer of which (Mr Pentland) found that its ele- 

 vation above the sea was 1986 toises (13,033 feet). Neverthe- 

 less, it must not be represented that the height of the table-land 

 between the Kwan-lun and the Himalaya, as well as in all the 

 rest of Central Asia, is equal throughout. The mildness of the 

 winters, and the cultivation of the vine -f-, in the gardens of 

 H'lassa, in the parallel of 29° 40'', — facts ascertained by the ac- 

 counts published by M. Klaproth and the Archimandrite 

 Hyacinth, — proclaim the existence of deep valleys and circular 

 hollows. Two considerable rivers, the Indus and the Zzambo 

 (Sampoo I), denote a depression in the table-land of Tibet, to 

 the north-west and south-east, the axis of which is .found nearly 

 in the meridian of the gigantic Javahir, the two sacred lakes of 

 Manassoravara and Ravana Hrada, and Mount Cailasa, or 



* In the Andes, I found that the mean height of the longitudinal val- 

 ley between the Eastern and Western Cordilleras, from the cluster of moun- 

 tains of Los Robles, near Popayan, to that of Pasco, as well as those in 2° 

 20' N. Lat. to 10° 30' g. Lat., was about 1500 toises (9843 feet). The table, 

 land, or rather longitudinal valley of Tiahuanaco, along the Lake of Titicaca, 

 the primitive seat of Peruvian civilization, is more elevated than the Peak 

 of TeneriiFe. However, according to my experience, it cannot be asserted 

 generally that the absolute height to which the bottom of the longitudinal val- 

 leys appears to have been raised by subterranean force, augments with the 

 absolute height of the neighbouring chains. In like manner, the elevation 

 of isolated chains above the valleys is very various, showing that at the 

 foot of the chain the raised plain is elevated at the same time, or has pre- 

 served its ancient level. 



-|- The cultivation of plants, whose vegetable life is almost limited to 

 the duration of summer, and which, despoiled of leaves, remain benumbed du- 

 ring winter, may be accounted for by the influence which vast table-lands 

 exert upon the radiation of heat ; but it is not the same with the less 

 rigour of winters, when we refer to elevations of 1800 to 2000 toises 

 (11,812 to 13,125 feet) at six degrees to the north of the equinoctial zone. 



+ The researches of M. Klaproth have proved tliat this river, which is 

 entirely sej)arated from the system of the Brahmaputra, is identical with 

 the Irrawaddy of the Burmese empire. 



