MONSOONS. 857 



nortliern edge, supposed to be the parallel of 30° north, the baro- 

 meter stands at about 29.45 inches. This barometric declivity 

 indicates that the south-west are stronger than the north-east 

 monsoons, and observations show that they are.* 



692. These are the winds — the south-west monsoons — which, 

 The summer rains comiug from the sea, Carry into the interior rains 

 of cherraponjie. foj, ^^^q gj^Q^^ watcr-shcd of India. They bear with 

 them an immense volume of vapour, as is shown by the rivers, 

 and confirmed by the rain-fall of Cherraponjie, and at 126 other 

 stations. Cherraponjie is 4,500 feet above the sea level. It 

 reaches quite up to the cloud region, and receives a precipitation 

 of 537;g- inches during the south-west monsoon, from May to 

 August inclusive. Col. Sykes reported to the British Associa- 

 tion, at its meeting in 1852, the rain-fall at these 127 places, 

 which are between the parallels of 20° and 34° in India. Ac- 

 cording to this report, the south-west monsoons pour down 

 during the three summer months upon this water-shed 29f 

 inches of rain. The latent heat that is liberated during the 

 condensation of the vapour for all this rain expands the air, 

 causing it to boil over, flow off, and leave a low barometer — a 

 diminished atmospheric pressure throughout all the region south 

 of the Himalaya. 



693. As long ago as 1831, Dov^ maintained that the south- 

 Dove and the west monsoon wa^ the south-east trade-Avind rush- 

 monsoons. ^^g forward to fill the vacant places over the 

 northern deserts. Dove admits the proofs of this to be indirect, 

 and acknowledges the difficulty of finding out and demonstrating 

 the problem. 



694. But any navigator who, during the summer months, has 

 The south-east trades occasion to travorsc the Indian Ocean from north 

 wesVmonsinr to south, may find that it is so. The outward- 

 bound Indiaman, who, when on his way to Calcutta, crosses the 

 equator in August, for example, will find the south-east trades, 

 as he approaches the line, to haul more and more to the south. 

 As he advances still farther north they get to the west of south. 

 Finally, he discovers that he has got the regular south-west mon- 

 soons, and that he has passed from the south-east trades into 

 them without any intervening calm. This in summer is the 

 rule ; it has its exceptions, but they are rare. Examining the 

 logs of a number of vessels taken at random for the passage in 



* Dr. Buist. 



