• 1835.] • Observations on tJie Flora of Courtallnm. 381' 



tlirough its whole thickness by a n-arrow pass leadiiig 

 directly across to the Malabar Coast. The effect of this 

 arrrangement is, as might be expected, that a portion of" 

 the south west monsoon passes over, modifying in a re- 

 markable degree the climate and vegetable products of 

 ^ this spot. Owing to this cause, early in June, Courtal- 

 lum is visited by strong westerly winds, -bringing with 

 them dense clouds, frequent, often heavy falls of rain, 

 which extend over nearly the whole of the recess, and 

 •covering the mountain tops with thick mist. While 

 this state of things continues, the rays of the siin are 

 intercepted by thick clouds, rapid evaporation is 

 kept up by frequent showers and strong winds, 

 and by the capacity of the air for moisture, being at the 

 game time increased, owing to its passing from a lower- 

 to a higher temperature.. 



The conjoint operation of these causes, produces a re- 

 'cluction in the temperature of from 10 to 15 degrees be- 

 low that of the adjoining plain and of the Carnatic gene- 

 rally, averaging about 75^^ while that of the plains is 

 ^"from 85 to 90 degrees. 



^ This great diminution of heat, combined with the re* 

 niarkable dryness of the air, even during rainy weather, 

 has most deservedly acquired for this spot a character 

 for salubrity, during the prevalence of the south west 

 monsoon, iinequalled perhaps by any other at a si- 

 milar elevation on the Coromandel coast.. Here, though 



■ barely 700 feet above the level of the sea, one may often 



' for weeks together be in the open air, at any hour bf 

 the day, being protected from the direct rays of the sun 

 by a thick canopy of clouds, and cooled by strong and. 



'dry winds. This peculiar dryness which has been long 

 remarked, but never so far as I have been able to leara 

 been accounted for, is I think satisfactorily explained on 

 the principle already mentioned, the change of capacity 



■iov moisture- which the air undergoes in passing' fro hi a 



