308 On the S?iow-line in the Himalaya, [April, 



the more remote cause of the periodical recurrence of the rains, there 

 can I think be little doubt, that the proximate cause of the condensa- 

 tion of by far the greater portion of the snow or rain that falls on the 

 snowy mountains, is that the current from the south is more damp or 

 hot than the air in contact with the mountains against which it blows ; 

 a relation which holds good in the winter as well as in the summer. 



Thus the air that comes up from the south, no sooner reaches the 

 southern boundary of the belt of perpetual snow, where the mountains 

 suddenly rise from an average of perhaps 8,000 or 10,000 feet to nearly 

 19,000 or 20,000, than it is deprived of a very large proportion of its 

 moisture, which is converted into cloud, rain or snow, according to cir- 

 cumstances. And the current, in its progress to the north, will be 

 incapable of carrying with it more moisture, than is allowed by the very 

 low temperature to which the air is of necessity reduced in surmounting 

 the snowy barrier, 19,000 or 20,000 feet in altitude, that it has to pass. 

 Nor can any further condensation be expected at all comparable in 

 amount to what has already taken place, as it would manifestly demand 

 a much more than corresponding depression of temperature ; and this 

 is not at all likely to occur, for the most elevated peaks being situated 

 near the southern limit of perpetual snow, the current on passing them 

 will more probably meet with hotter than with colder air. 



It is, I conceive, to precisely similar causes, that we should attribute 

 the great amount of rain that is known to fall at Mahabaleshwar, on the 

 Western ghats, at Chira-punji, in Sylhet, and generally, though the quan- 

 tity is far less, along the most southern range of the Himalaya itself > 

 and it is curious to observe that the comparative dryness of the less 

 elevated country to leeward also holds good in these cases. In the 

 Deccan, the country immediately to the east of the western ghats, Col. 

 Sykes tells us, that " the rains are light, uncertain, and in all years 

 barely sufficient for the wants of the husbandman." On the same 

 authority we find, that while the mean fall of rain for 3 years at Poona 

 was about 27 inches,* that at Mahabaleshwar for 1834 was no less than 

 302 inches. f Although I have not the exact figures to refer to, I know 

 that the rain at Nainee Tal on the external range of the Himalaya, is 

 about double what falls at Almora, not 30 miles to the north. 



* British Association's 7th Report, p. 236. 



t Ibid, 9th Report, p. 15, (Sections.) The exact amount is 302.21 inches. 



