1849.] exercised by Trees on Climaie. 457 



The fall of rain at Thodawully at 30 miles from the sea is even 

 greater than that at Caldoorty on the Quilon line at 40, but the 

 fall of rain appears to increase as we go north, on the sea coast, as 

 well as inland, and the actual difference here, between the coast and 

 the inland stations, is less than on the Quilon line, as might be ex- 

 pected from the spurs and ridges from the main chain of ghats being 

 of less depth and less altitude. 



At Shalakurray, 30 miles from the sea, the fall is nearly double 

 that at Quilon, — whereas at Thodawul!}-, also 30 miles from the sea, 

 the fall is barely half more than at Cochin or Alleppy. 



A third series of observations is about 35 miles north of Cochin 

 from the sea coast, near Chowgat by Trichoor to the town of Chittoor 

 in the Cochin district of the same name, and in the very midst of the 

 great opening in the ghats at Palghatcherry. 



I have no observations at Chowgat, but 1 

 earae as at Cochin thus : 



lave assu 



med that it is the 



Chowghat, 

 Trichoor, . . 

 Chittoor,... 



Distance. 



Altitude. 



Eain. 



Miles. 



Eeet. 



Inches. 



Sea Coast 



12 



88 



12 



50 



101 



52 



300 



60 



I was not prepared at first to account for the greater fall of rain 

 at Trichoor, 12 miles inland, for the country immediately about 

 it is flat and open, but there are numerous and continuous high chains 

 of hills crossing the whole country, to the eastward, within 5 or 6 

 miles ; and it may therefore be considered as another and most in- 

 teresting proof of their eflect, in augmenting the fall of rain. 



On the two former lines the fall of rain increased as the moun- 

 tain tracts were approached and entered, but on this last line the 

 very reverse takes place, the fall of rain at Chittoor 52 miles from 

 the sea being only 60 inches, or but little more than one half of the 

 fall on the coast ; but on this line, although crossed by a belt of for- 

 est, there are no mountain chains to intercept and lead to condensa- 

 tion of the vapour, and which is of course therefore rapidly absorbed 

 by the dry and heated air of the province of Coimbatore on the east 

 of the ghats. 



There cannot perhaps be a more beautiful illustration of the 

 effect of mountain chains, in arresting and condensing the vapour, 

 than the generally luxuriant forests which clothe the eastern as well 



