RIVER HOOGLY. 



261 



the south-west monsoon sets in. With the south-west winds, the car- 

 rents set up the Bay of Bengal, and gradually raise the sea, at its head, 

 several feet, raising with it the Hoogly, long ere the freshes are felt. The 

 dotted curve line in map No. 1, will shew this rising of the sea, and river 

 by the wind, and currents. This cause continues till October; the pour- 

 ing of the rivers into the Bay of Bengal, during the months of August 

 and September, and the change of wind at the end of October, give the 

 currents a set in the contrary direction, and gradually restore the sea 

 and the river to the state they were in, in March. 



The effect of the two monsoons upon the currents, and the height of 

 the sea, in the Bay of Bengal may, therefore, be considered as that of two 

 long unequal tides, during the year, eight months of flood, and four 

 months of ebb. 



In conformity with these periodical local causes — partial ones have 

 a corresponding effect, thus strong southerly winds raise the tides, in the 

 Hoogly, whilst northerly ones depress them. 



The freshes, or floods of the rivers, are a prominent periodical local 

 cause, operating upon the tides of the Hoogly at Calcutta. 



The Ganges begins to rise from the melting of the snow, as early as 

 the beginning of May, but its rising does not sensibly affect the Hoogly 

 till the beginning of July, at that period, so large an accession of water 

 is thrown into the Hoogly, that its level is bodily raised both at high and 

 low water. The last is so remarkable, that the low water of the freshes 

 (neap tides) is higher than the high water (neap tides also) of the dry 

 season, by several feet. 



The 



