CLIMATE. 121 



Himalayas or to the Punjab plain. The effect is that the air over 

 the centre of the Peninsula expands, lifts the higher layers of air, 

 causes them to flow away on all sides and produces a centre of 

 comparatively low pressure. Into this centre presses the heavier 

 atmosphere from the sea, causing the sea breezes so characteristic 

 of the spring months. 



These air currents deviate, however, from their original course 

 in consequence of the law that everything moving over the 

 northern hemisphere presses towards the right. The consequence 

 is that the winds, which hit the Madras coast at this time of the 

 year, are mostly south-easterly breezes, those which hit the 

 southern half of the west coast come from the south-west, while 

 those which hit the land to the north of Bombay become gradually 

 more and more north-westerly winds. These phenomena have 

 the result that Madras and the southern part of Bombay are passed 

 over by moist sea winds which drop a portion of their moisture, 

 producing during this period a rainfall of 3 to 6 inches. The 

 above-mentioned north-westerly breezes, however, descend from 

 the table land of Baluchistan ; they are dry and become more so 

 in passing over the heated plains of Sind, Cutch and Kathiawar. 

 These are the breezes which are known as the hot winds in the 

 Bombay Presidency, in North-Western and Central India. At 

 times they find their way as far as Bengal and Orissa and far down 

 into the Peninsula. 



Up to May the sea winds are light, and they bring only a 

 moderate amount of rain, as the air is then drawn chiefly from the 

 sea immediately surrounding the Peninsula. With the advancing 

 season towards the end of May, the winds become stronger and 

 stronger bringing more and more rain, until, in the course of three 

 or four weeks, they have invaded the whole of the west coast of 

 India and the northern and eastern coasts of the Bay of Bengal, an 

 event which is known as the bursting of the monsoon. Now the 

 winds are a northern continuation of the south-east trade winds 

 coming from more distant equatorial regions, the great reservoir of 

 moist air. Of late the theory has been advanced that the south- 

 west monsoon is due to, or assisted by, a system of low pressure at 

 the head of the Persian Gulf and a consequent indraft of the south- 

 east trade winds. It seems to require further confirmation. 



The strength of the monsoon rains differs greatly in different 



