126 Report on the Progress of the Magnetic Survey. [No. 2. 



Shyok and in the valleys of their larger tributaries, but at greater 

 heights southerly winds prevail as a general rule up to the water- 

 shed of the Kuenluen. 



These southerly winds are compensated by northerly winds which 

 have been observed in Turkistan by my brothers, at the same time 

 that I constantly experienced southerly winds on the east of the 

 Kuenluen mountains. 



4. The quantity of rain and snow that falls in the western parts 

 of the Kuenluen, in the environs of the Mustak Pass, &c, is con- 

 siderably more than in the eastern parts of the chain about Karako- 

 rum ; in consequence the snow line near Mustak (17,900 ft.) is much 

 lower than on the Karakorurn mountains (18,600 ft.) determined by 

 my brothers ; in consequence also, a great number of large glaciers 

 occur in the western Kuenluen, whilst in the very rainless Kara- 

 korum group glaciers of a similar size do not exist. 



The greater amount of rain and snow which falls in the western 

 Kuenluen seems especially to be due to the wide opening which 

 exists along the southern parts of the valley of the Indus. 



Through this opening the moist winds from the plains of India 

 can penetrate more freely to the high ranges of Mustak than to the 

 Karakorum mountains, where they have to cross the high Himala- 

 yan ranges. 



The total amount of rain and snow on the western Kuenluen 

 ranges, may be estimated to be about 10 inches a-year ; by far the 

 greater part of which is snow-fall in winter. There is very little 

 rain in summer. The total amount of rain and snow in the valleys 

 of the Indus and Shyok is less than in the Kuenluen. 



5. Owing especially to the absence of summer rains, and to the 

 dryness of the heated atmosphere produced by the insolated rocky 

 slopes of the valleys, no natural forest of any kind exists in the 

 valleys of western Thibet, though they are only elevated 7,000 to 

 8,000 Eng. feet above the sea. 



At an elevation of 12,000 to 15,000 Eng. feet a rich shrub vegeta- 

 tion of a large species of juniper, of willows and birches is general- 

 ly met with ; below 12,000 feet this shrub vegetation becomes much 

 thinner and disappears almost entirely, owing to the greater heat 

 and dryness. 



