696 Limits of Perpetual Snow in the Himalayas. [July, 



or 18,500 feet on the north face of the same hill. These latter esti- 

 mates are Lieut. Strachey's, and they are, I think correct, while the 

 southern height of 20,000 feet is an approximation only. 



I have taken the height of the Manasarawar lake, viz. 15,000 feet, 

 in making this sketch, but even Humboldt's mean elevation of Tibet, 

 viz. 11,500 feet (Cosmos, I. 330,) will not affect the argument, that the 

 distance between the planes of the mountain bases and of the snow 

 limits goes on decreasing as the former ascend. 



Quantity of snow falling in Tibet, and the permanency or renewal 

 of snow generally. — With regard to the quantity of snow which falls 

 to the northward of the main peaks of the Himalayas, I may refer to 

 my statement at p. 238, of the 148th No. of the Journal, where I say 

 that it did not appear to exceed two feet and a half in depth, where 

 not drifted. This refers to the tract around the junction of the Sutlej 

 and Spiti rivers. In addition to the details there given, I may also 

 mention that the larger streams began (in 1842) to swell after the 

 middle of February. This was due, I would say, to the radiation from 

 the mountain masses causing the lower surface of the snow to melt — 

 the recently accumulated snow itself forming a protection against the 

 chilling winds, and so allowing the earth to part with its heat. At this 

 period the temperature of ordinary springs was about 42°, while the 

 air at sunrise was sometimes below zero, and the mercury would not 

 rise above 60°, when exposed to the sun's rays in the early part of the 

 afternoon. I state these particulars partly in support of what I con- 

 sider to be Capt. Hutton's meaning with regard to snow not being per- 

 petual — an opinion to which Lieut. Strachey somewhat slightingly 

 alludes.* Both observers are right, because the one simply means that 

 the snow is ever being simultaneously destroyed and renewed, and the 

 other that hills of a certain elevation always exhibit a covering of snow. 



The Tibet of the Himalayas not a plain or table-land. — Lieut. 

 Strachey, and indeed most people, talk of the " plains" or table-land" 

 of Tibet, but I doubt whether between Imaus and Emodus, or any 

 where in the valleys, or basins of the Indus and Brahmaputra to the 

 north of the Himalayas, there are any plains. The range separating 

 the upper courses of the Indus and Sutlej is indeed inferior in height 

 to that which gives rise to the Ganges and Jumna, but it is still a lofty 

 * Journ. As. Soc. of Bengal, April 1849, p. 302, note. 



