356 PHYSICAL GEOGRAPHY OF THE SEA, AND ITS METEOROLOGY. 



towards it ; instead of being a place of bigh, the medial line is 

 now (§ 657) a place of low barometer. By November the north- 

 east monsoon has pushed the place of equal contest as far down 

 as the parallel of 5° north. 



691. Each monsoon, like the trade-winds, blows from a higher 

 The barometric des- to a lower barometor. Taking up the clew from 

 centof themonsoofls.^|-^jg fg^^t, and rosorting again to the graphic method 

 for illustration, we may ascertain, with considerable accuracy, 

 not only the relative strength of the north-east and south-west 

 monsoons of the sea, but also the mean height of the barometer 

 in the icterior of India during the south-west monsoon, sup- 

 posing that monsoon to go no farther than the mountain range, 

 which may be taken at a mean to be about the parallel of 30° 

 north. Now, taking the mean height of the barometer at the 

 equatorial calm belt to be (§ 362) 29.92 inches ; the mean height 

 in the calm belt of Cancer to be 30.21 inches, the line N.E. of 

 the Diagram D will represent the average barometric decHvity of 



Diagram D. 

 0" "K 5° Xat Iff 15° 



20' 



30" 



Bar .2 



.1 

 so.o 



21>.0 



the north-east monsoons generally. The mean height of the 

 barometer during the three months of June, July, and August, 

 when the south-west monsoons are at their height, is. 



For Calcutta 29 . 55 inclies. 



„ Bombay 29.65 „ 



„ Madras 29.73 „ 



The line S.W. represents the mean barometric declivity of the 

 south-west monsoons at their height, and indicates that at their 



