Snoiv-Line in the Himalaya. 349 



pears to have no dependence on increase of distance from the 

 southern limit of the belt of perpetual snow. Among the 

 more evident causes of the irregularities in the melting of 

 the snow, may be mentioned, the powerful action of the heavy 

 summer rain on the southern face, as compared with what 

 falls as little more than a drizzle on the northern ; the pro- 

 tection afforded from the I'adiation of the sun by the heavy 

 clouds so frequent in the south, contrasted with the i^elative 

 slight resistance of the less dense but not uncommon clouds 

 on the north ; the differences in the temperature of the air 

 that acts on the lower edge of the snow produced by the 

 difference of height of the snow-line on the opposite faces of 

 the chain ; and, lastly, the differences of the temperature of 

 the air, and of the amount of radiation and reflection depend- 

 ent on the differences in the state of the surface of the earth, 

 which on the south is densely clothed with vegetation, while 

 on the north it is almost bare. 



Before concluding I will observe, that the height at which 

 it is certain that snow will fall every year, in this region of 

 the Himalaya, is about 6500 feet ; and at an elevation of 

 5000 feet it will not fail more than one year out of ten. The 

 least height to which sporadic falls of snow are known to 

 extend, is about 2500 feet ; and of such falls there are only 

 two authentic instances on record, since the British took pos- 

 session of Kumaon, viz., in 1817 and 1847. Thus we see that 

 the regular annual fluctuation of the snow-line is from 9000 

 feet to 10,500 feet, and it occasionally reaches even 13,000 

 feet. M. Humboldt informs us that under the equator at Quito, 

 the fluctuation is GOO toises (3800) ; that at Mexico it reaches 

 1350 toises (8600 feetj ; and the greatest fluctuation that he 

 mentions is that in the south of Spain, which amounts to 

 1700 toises (10,900).* 



A brief recapitulation of the principal results of this inquiry 

 will shew us, that the snow-line, or the southern edge of tlie 

 belt of perpetual snow in this portion of the Himalaya, is at 

 an elevation of 15,500 feet, while on the northern edge it 

 reaches 18,500 feet ; and that on the mountains to the north 



* Asi<i Contrale, t. iii. p. 279. 

 VOL. XLVII. NO. XCIV. — OCTOBEU 1849, 2 A 



