Attempt to determine the mean height of Continents. 333 

 20 toises ; while the Himalaya and the Houen-lun, which is 

 a prolongation of the Hindoo-Kho, with the plateaux of Thibet, 

 which connect the Himalaya with the Kouen-lun, will only pro- 

 duce an effect of 56 toises. In the examination of the consi- 

 derable relief between the plains of the Indus and the de- 

 pressed plateau of Tarini, which, on leaving Kaschgar, in- 

 clines to the east towards Lake Lop, it is necessary to exa- 

 mine with more care the point near the meridian of Kaylasa, 

 and the two sacred lakes of Manasa and Ravana-Brada, on 

 leaving which the Himalaya no longer runs from east to west 

 parallel with the Kouen-lun, but takes the direction from 

 south-eastto north- west, and reunites at the projecting ridges of 

 Tsun-ling. The altitudes of the numerous passes of Bamian, 

 as far as the meridian of Tschamalari (24,400 feet), by which 

 Turner reached the Thibetian plateau of H'Lassa, are likewise 

 known for an extent of 21^ of longitude. The greater part 

 of them present a very uniform height of 14,000 English feet, 

 or 2200 toises, a height which is not of rare occurrence in the 

 passes of the chain of the Andes. The great route which M. 

 de Humboldt followed from Quito, on his Avay to Cuen^a, 

 was, for example, at Assuay (Ladera de Cadlud), and without 

 snow, of the height of 2428 toises, that is to say, 1400 feet 

 higher than this pass of the Himalaya. The passes, as has 

 been stated, give the mean height of mountains. 



In a memoir on the relations between elevated summits or 

 culminating points, and the height of mountain chains, M. 

 de Humboldt has demonstrated that the chain of the Pyre- 

 nees, calculated from twenty-three passes, was 50 toises high- 

 er than the mean chain of the Alps, although the culminating^ 

 points of the Pyrenees and the Alps were in the proportion o'f 

 1 to 1 ^15. As the insulated passes of the Himalaya, for ex- 

 ample, the Niti-Gate, by which we penetrate into the plain 

 of the Cashmere goats, rise to the height of 2629 toises, ?.I. 

 de Humboldt has not admitted for the height of the Himalayan 

 chain 14,000 English feet, but he proposes to fix it, altliough 

 perhaps the elevation may be still too considerable, at 15,500 

 feet, or 2432 toises. The plateau of the three Thibcts of 

 Iscardo, Ladak, and ITLassa, is a prominence between two 

 chains which unite with each other (the Himalaya and the 



