178 IWCS GASEOUS VAPOURS. 



whilst the others were only j"ust able to surmount 

 the pass.^ 



The descent from the pass was even more gra- 

 dual than the ascent. It continued for fifteen miles, 

 and terminated at the stream called Nomokhun, 

 flowing in a gorge of which the height above the sea 

 was 1 1,300 feet. And this was the lowest elevation 

 in the whole of our route across Northern Tibet. 

 Beyond the Nomokhun the ground gradually rises 

 to another range, the Shuga (Chouga), lying 

 parallel with the Burkhan Buddha and terminating 

 as abruptly on the west, where it abuts on the 

 Tsaidam plains." This range is somewhat longer 

 than the preceding. It commences with the Urun- 

 dushi mountains on the east, where the Shuga gol 

 also rises. This stream is 280 feet wide'^ where we 



1 In his description of these mountains (ii. 210-212), Hue says that 

 the range is remarkable for the presence of noxious gases on its north- 

 ern and eastern face. He continues to relate how he himself and his 

 companions felt the injurious effect of these gases on the pass. An 

 exactly similar description may be fcmnd in a translation of a Chinese 

 itinerary from Si-ning to Lhassa (Trans, of the Russ. Imp. Geogr. Soc. 

 1873, vol. ix. pp. 298-305), where it is said that in twenty-three places 

 on this road deleterious exhalations, ' chan-tsi' are met with. We were 

 for eighty days on the plateau of Tibet and never once experienced 

 the ' pestilential vapours ' or exhalations of ' carbonic acid gas.' 

 The difficulty of marching here as well on the perfectly level parts of 

 Northern Tibet, the catching of the breath, fatigue and giddiness, arc 

 of course attributable to the enormous elevation and rarefaction of the 

 air at those altitudes. This also accounts for the argols burning so 

 badly. Again, if there really were carbonic acid, or other noxious 

 gases, how could the Mongols live there in summer with their herds, 

 or how could the vast troops of wild animals pasture here and farther 

 in the desert ? [See also remarks in Introduction.] 



- In all probability these two ranges, i.e. the Burkhan Buddha and 

 Shuga, unite in the extreme west, where they abut on Tsaidam. 



^ This was the width of the ice in the channel in winter ; the stream 

 itself is probably much narrower. 



