1849.] Remarks on the Snow line in the Himalaya. §&5 



wur."* Now it seems to me by no means improbable that this very 

 difference in the features of the two tracts may be sufficient to account 

 for the difference in the phenomena observable in each, and that if 

 Humboldt's theory of radiation from the plains of Tibet is sufficient to 

 account for the retreat of the snow to the heights of the northern face, 

 the want of similar plainsf in the western tracts will of course pre- 

 clude such radiation from acting on the northern face of the western 

 mountains, and thus the greater heat of the southern side, added to 

 the periodical rains and to the violence of the winds in winter, will 

 leave snow on the northern long after it has disappeared from the 

 southern aspect. 



Lieut. Strachey admits that the rains have a powerful effect in melt- 

 ing the snows, but his want of knowledge of the localities to the west- 

 ward has led him into an error when he supposes that the monsoon 

 does " not extend up the Sutlej beyond the point where the Buspa 

 falls into it ;" the truth being that Chini, which is itself farther up and 

 situated in the gorge where the Sutlej breaks through the outer snowy 

 range, is full within the monsoon, as both Captain Jack and I experi- 

 enced ; beyond this point the rains are light and uncertain, but they 

 nevertheless extend to the head of the district, for clouds and vapours 

 pass onwards through the valley of the Sutlej even to the upper parts 

 of Kunawur, and exercise great influence in clearing the southern slopes 

 of their snow ; and although Lieut. Strachey has assumed that clouds 

 protect the snow, by warding off the direct rays of the sun, he overlooks 

 the fact that such clouds betoken a humid atmosphere, which is quite 

 as inimical to the duration of. the snow as the sun's rays, and he 

 might at least during his scientific researches in Kumaon, have learnt 

 the fact that thaws are more rapid in cloudy weather, than in a dry 

 and unclouded atmosphere, such as that which he acknowledges to be 

 the general characteristic of the northern aspect. 



Dr. Lord's remarks on the Hindu Cush coincide apparently with 

 mine to the north of the Bissehir range, and since Webb's observations 

 in Kumaon are found to be only locally true, there can be little doubt 



* Cal. Journ. Nat. Hist. No. 19. 



f Captain Cunningham seems to doubt the existence of any plains at all ! — Vide 

 J. A. S. 205, for 1849. 



6 i 



