100 STEPPES AND DESEKTS. 



and in Kosmos, Engl. ed. vol. i. note 403 ; S. 483 of the 

 original.) 



A letter which I have just received from India from Dr. 

 Joseph Hooker, who is engaged in meteorological and 

 geological researches, as well as those connected with the 

 geography of plants, says : " Mr. E odgson, who we regard 

 here as the geographer best acquainted with the hypsometric 

 relations of the snow ranges, completely recognises the 

 correctness of your statement in the third part of the 

 Asie Centrale, respecting the reason of the inequality in the 

 height of the limit of perpetual snow on the northern and 

 southern declivities of the Himalaya. In the ' trans Sutlej 

 region' in 36 lat. we often saw the snow limit only com- 

 mence at an altitude of 20000 English feet, while in the 

 passes south of the Brahmaputra, between Assam and Bur- 

 man, in 27 lat., where the most southern Asiatic snowy 

 mountains are situated, the limit of perpetual snow sinks 

 to 15000 English feet/" I believe we ought to distinguish 

 between the extreme and the mean heights, but in both we 

 see manifested in the clearest manner the formerly contested 

 differences between the Thibetian and the Indian declivities. 



My statements respecting the mean 

 height of the Snow-line in the Hima- 

 laya. (Asie Centrale, torn. iii. p. 326.) 



Paris feet. Eng. feet. 

 Northern declivity 15600 ... 16626 



Extremes according to Dr. Joseph 

 Hooker's letter. 



Paris feet. Eng.feet. 

 Northern declivity 18764 . . . 20000 



Southern ' 12180... 12981 i Southern " 14073... 15000 



Difference 3420 3645 Difference 4691 5000 



The local differences vary still more, as may be seen from 



