ffrg On the Land Winds of Coromandel, and their Causes, 



By this we see, that the clouds formed on the Ghauts, 

 charged with water and electricity (by causes I am not now 

 to investigate), are drawn to the westward, whilst the heat 

 which, during the formation of these clouds, must neces- 

 sarily be discharged, is carried to the east or to the lower 

 parts of the coast, and causes the properties for which the 

 land winds are so remarkable. 



I have acknowledged already, that the heat occasioned 

 by the power of the sun in this season, contributes to the 

 aggregate of it in the wind; but I must observe also, that 

 it acts only as a secondary cause, and passively, by pre- 

 venting its absorption and diminution in the career over a 

 variety of substances, particularly moisture* with which it 

 would combine, if they had not been previously removed 

 or incapacitated. 



In colder climates, this absorption takes place in a greater 

 degree, as substances are abundant with which the heat 

 produced by the formation of rain can combine and be- 

 come imperceptible*. It is, however, there also often m* 

 marked, that the heat of the sun in a cloudy day is more 

 powerful than at any other time. In common this is 

 ascribed to the reflection of the rays of the sun from the 

 clouds ; but I opine it is often the consequence of the for- 

 mation of water in the clouds_, which obscure the sky at 

 that moment. 



It has been observed, that the heat of the land winds is 

 not felt on the top of high hills, or on plains of a very in- 

 considerable perpendicular height above those in which it 

 rages most violently ; as for example, in Mysore near the 

 Ghauts, which is only about five hundred feet higher than 

 the valleys immediately below. This might be considered a 

 weighty objection against my theory ; as heat, considered 

 in the light of an elastic fluid, expands equally on all sides; 

 and from whatever cause it proceeds, it should be supposed 

 to extend even further where it meets with less resistance, 

 as from the air in higher regions, which is known to be 

 lighter and more penetrable than near the earth. 



"But the reverse takes place; for almost immediately 

 above the clouds no other heat is perceptible than what 

 might be owing to the nature of the climate. 



This circumstance may be accounted for by the dimi- 

 nished density of the air in the lower parts of the country, 



* Carl Dundonald's Treatise, p. CO. " The frequent changes in the de- 

 gree of heat arid cold in the atmosphere are to he aserihed more to the alter- 

 nate disengagement and fixation of heat by chemical combination, than to 

 the effect! of the solar raya." 



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