966 Remarks on the Snow line in the Himalaya. [Sept. 



that Dr. Lord's surmise relative to the effect of heat radiating from the 

 high plains of Cabul and Koh-i-damun is correct. 



In regard to "perpetual snow," Lieut. Strachey has rightly under- 

 stood me, and I again repeat that there is not and cannot be any such 

 thing, and that any assertion to the contrary must necessarily convict 

 its author of being utterly ignorant of the well known fact, that 

 nothing in nature is perpetual or everlasting. All matter is ever un- 

 dergoing change ; the very rocks are crumbling down beneath the force 

 of atmospheric agents ; the atmosphere itself is constantly undergoing 

 change and renovation ; the water and the snow alike return to it in 

 the form of vapour. Where then is there a sign of perpetuity ? My 

 opponent should have remembered, when he undertook to censure my 

 supposed illogical reasoning, that there is a wide difference between 

 a hill covered with perpetual snow, and one that is perpetually cover- 

 ed with snow ! — " The mere continuance of snow on any spot," says 

 no less authority than Professor Forbes, " does not suppose that snow 

 never melts there ; were that the case a progressive and unceasing 

 accumulation would be the result ; the position of the snow-line, or 

 what is often erroneously called the line of perpetual congelation, is 

 determined solely by this circumstance, that during one complete revo- 

 lution of the seasons or in the course of one year, the snow which 

 falls is just melted and no more."* 



Thus Lieut. Strachey's observations, although useful in corroborating 

 those of Webb and others, in reality leave the question precisely 

 where it was, namely, that while in Kumaon the elevation of the snow 

 line is greater on the northern aspect than on the southern ; the truth, 

 on the Hindu Cush, and as far as observation goes, in the Tartar dis- 

 tricts north of the Bissehir range, is actually the reverse ; proving as 

 I long since stated, and now repeat, that the facts on which Humboldt 

 relied as applicable to the whole extent of the Himalaya, are found to 

 be purely local, and dependent altogether on the physical features of 

 the country to the north and south of the water-shed. 



* Forbes' Travels through the Alps, p. 18. 



