Mr. H. T. Colebrooke's Remarks on the Setlej River. 379 



mountaineers of the Himalaya, who feel it not less sensibly than strangers, 

 ascribe the sensation to presumed exhalations of a supposed poisonous vege- 

 tation at that vast height. At a less elevation no such effects are perceived. 

 Inhabited places were visited by Messrs. Gerard, at the heigiit of more than 

 13,000 feet above the sea ; and cultivated fields were seen at 13,600 feet, 

 and cattle pasturing at a still greater altitude. 



The diary of this journey supplies ample confirmation of a position ad- 

 vanced by me some years since, in reply to some hasty inductions, grounded 

 on imperfect experiments and insufficient observations, as to the limit of 

 perpetual congelation. It was not to be supposed that the same mean tem- 

 perature, or the same maximum of it, would occur under a given geogra- 

 phical line, at equal elevations, whether of a solitary mountain or an extensive 

 cluster; whether of an isolated peak, or a sequestered glen. On the con- 

 trary, it seemed obvious that reverberation of heat must produce like effects 

 of concentrated warmth, at the level of the sea, and on the table land of 

 mountains. Accordingly, it does appear, that in the exterior chain of the 

 Himalaya, where heat is reflected to it but from one side, ithe warmth is 

 much less than in the interior cluster, where there is reverberation from all 

 quarters. Capt. G. has repeatedly adverted to these important facts. 



He has constantly attended likewise to very interesting questions con- 

 cerning the geography of plants, and especially regarding the limits of 

 vegetation. In abridging his diary, I have seldom suppressed any circum- 

 stance bearing upon these points ; but have commonly retained the particu- 

 lars, at the price, perhaps, of some tediousness and a little repetition. The 

 greatest elevation, at which plants of a notable size are remarked, is 17,000 

 feet. The utmost limit of vegetation of mosses and lichens must doubtless 

 reach further. 



The greatest height attained during this journey was 18,612 feet; viz. at 

 Mdnerang pass. Next to it is the Keubrang pass, at 18,312 feet above the 

 sea. Twice, in former journeys, Messrs. Gerard scaled the stupendous 

 altitude of a station on Pargeul, measured twice barometrically 19,411 feet, 

 and now confirmed trigonometrical ly, not without a surmise of a near 

 approachto 19,500 feet above the level of the sea. 



At tile elevation of 16,200 feet, on the confines of Chinese Tartary, 

 ammonites were picked uj). If not precisely //( sila, they probably had not 

 come from a remote situation ; for the specimens are of ammonites them- 

 selves, not adligrdma stones containing their impressions, and therefore not 



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