464 



Noies on the Influence 



[No. 36, 



estimate is attempted to be formed of the actual area cleared of 

 forests within the last hundred years. 



My own attention has of late years been much given to the 

 subject of the fall of rain, as connected with the vicinity to high 

 ranges of mountains : — I had noticed the accounts of the great annual 

 fall of rain on the Mahabaleshwar hills, and at Merkara in Coorgh ; 

 and several years ago, with a view to similar observations, I estab- 

 lished a rain guage on the summit of the high range of ghat moun- 

 tains 22 miles east of Trevandrum, and where I found the fall of rain 

 to be from 4 to 6 times the quantity on the sea coast. The obstruc- 

 tion to the passage of the vapour from these mountain chains, and its 

 consequent condensation, the monsoon winds being nearly at right 

 angles to the line of ghats, seemed to me to offer so decided and sa- 

 tisfactory an explanation of the phenomena, that I at once adopted it. 

 These observations on Uttree MuUay and other tables of the fall of 

 rain, which I have for several years past been collecting, although 

 without reference to, or in illustration of any particular theory, may 

 be of some interest in the present inquiries, as to the effect of forests 

 in promoting the fall of rain. 



I have established rain guages all along the sea coast from Cape 

 Comorin to the latitude of Ponany, and I have also by the assistance 

 of friends, been enabled to get several sets or lines of registers ruTi- 

 ning directly inland ; and perpendicular to the line of coast, for a dis- 

 tance of about 60 miles ; thus exhibiting, not only the effect of dis- 

 tance from the sea,but also that of contiguity to the great chain of ghats 

 separating Malabar from the provinces of the Carnalic. 



The first of these inland lines is from Quilon to Shenkotah and 

 Palamcottah, with rain guages at 



Inland Lines. 



Quilon, 



C Puttnapoorum. . . . 



I^ept by W. 3 Shalakurray, 



Huxham, Esq. ) Koraventavalum, 



V. Caldoorty, ...... . . 



Line of G-hats. 



Shenkotah. 



Palamcottah 



Distance. 



Miles, 



Sea Coast 

 25 

 30 

 36 

 41 



52 



70 



Altitude 

 above Sea. 



Feet. 



25 

 150 

 160 



350 

 750 



600 

 150 



E-ain. 



Inches. 



65 

 99 

 106 

 113 

 128 



44 

 24 



