360 PHYSICAL GEOGRAPHY OF THE SEA, AND ITS METEOROLOGY. 



the monsoons, for the annual changing at the same place is very 

 regular. 



700. Theory, therefore, points to a place in Northern India, 



?f°cL!cer h^^ii^hed "^^^^^^ ^^ ^^^^ *^^ uorthem limits of the south-west 

 to the north. mousoon, whoro the mean height of the barometer 



during the rainy season (§ 691) is about 29.5 inches, the mean 

 height at the equator being 29.92 inches. Into this monsoon 

 place of low barometer over the land the wind rushes from the 

 north-east as well as the south-west. The place of high pressure 

 towards the north from which it rushes is under the calm belt of 

 Cancer. Hence this belt is also pushed north, and made to 

 occupy, in summer at least, the position over land somewhat like 

 that assigned to it on Plate VIII. In the south-west monsoon 

 the Malabar coast has its rainy season, so that the air over the 

 peninsula is permanently kept more or less in a rarefied state, by 

 the liberation of latent heat from vapour as actual observations 

 abundantly show. 



701. The equatorial calm belt in the Indian Ocean is a 

 The curved form of docidcd curvo. The pcculiar form may be ascribed 

 beSThelnd^ai"^ *^ ^^^ moteorological influence of the Indian penin- 

 ocean. sula upou the calm belt, and in this way : The 

 north-east monsoon briugs the rainy season to the Coromandel 

 coast and to the east coast of Ceylon. This rainy season em- 

 braces the land rather than the sea. The latent heat that is 

 liberated during these rains, together with the effect of the solar 

 ray upon this tongue of land, has the effect of expanding the air 

 over it, and so "deadening" the north-east monsoon. In the 

 mean time, the meteorological influences from Africa on one 

 side, and Australia on the other, tend to draw the wind in towards 

 those lands and so retard the edges of the south-east trades, thus 

 giving the calm belt the curved form shown in the plate. 



702. In the winter-time, and during the north-east monsoon, 

 The wintermon- there is in the calm belt which intervenes between 

 ^^^^- that monsoon and the south-east trades, a belt of 

 winter or westerly monsoons. It, too, is curved, as shown (Plate 

 VIII.) by the two lines drawn to represent its mean limits about 

 the 1st of March. This^is a most remarkable phenomenon, for 

 which no satisfactory explanation .has been suggested. It ex- 

 tends nearly, if not entirely, across the Pacific Ocean also, and 

 the winds all the way in it prevail from the westward. The 

 extreme breadth of this winter monsoon belt is about 9° or 10^ 



