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On the Tides of the River Hugli. 
[OCT, 
lowing abstract will be useful, as conveying a general summary of the tides of the 
Hugli. From the point of lowest low water in the dry season, to that of the high- 
est high water in freshes, is twenty feet ten inches. 
The greatest mean rise of tide from low to high water mark, takes place in 
March, April, and May, and is fifteen feet ten inches- 
The greatest mean rise of tide from low to high water mark, in the freshes, is 
ten feet. 
The smallest mean rise of tide takes place in the freshes, and is, at neap tides, 
only three feet six inches. 
The smallest mean rise of the tide in the dry season, neap tides, is four feet. 
From the lowest fall of the river, to high water mark, neap tides, in February, 
is eight feet. 
From the lowest fall of the river to low water, in the freshes, neap tides, is 
twelve feet*. 
The river is at its lowest, in the beginning of March. 
The river is swollen by the freshes in July, August, and September, and part of 
October. 
At the beginning of November, although the freshes are out of the river, it is 
upwards of three feet higher at low water, than in March. 
The river is in the most quiescent state, during the months of November, De- 
cember, January, and February , during these months the night tides arc higher 
and more rapid than the day tides, and there are, on some occasions, bores at night. 
The strongest flood tides, and the greatest mean rise of the tides, are in March, 
April, May, and June. The day tides in these months, are higher, than the night 
tides. 
The strongest freshes are in September. 
In July, the strength of the flood tides is counteracted by the freshes, and this, 
therefore, is a moderate month, as regards tides. The bores also are moderated 
as a consequence. 
In August, the flood tides are overcome by the freshes, and the bores are mode- 
rate ; should there be a high parallax of the moon, however, the great height of the 
sea in this month, will cause a considerable bore. 
In September, the freshes are at their height ; there is no visible tide off Calcutta, 
the ships do not swing up, and the river water is perfectly sweet, far beyond Sau- 
gor in the open sea. The high parallax of the moon at the equinoxes, with the 
great height of the sea, produces a heavy bore in this month. 
The Bores. The bores in the Hugli occur only on the highest, or at alternate 
spring tides: their appearance may, with certainty, he predicted by the season of the 
year, and the parallax of the moon. During the months of November, December, 
January, and February, or on the periodical ebb of the sea, when the currents are 
settting down the Bay, the tides, as may be supposed, are languid, and conse- 
quently during this period there are no hores^-. 
As soon as the south-west monsoon sets the currents up the Bay, the sea begins 
to rise, the tides become strong and high, and bores follow in their train ; when- 
ever the parallax of the moon is high on the springs during the south-west mon- 
soon, bores will certainly make their appearance ; and when strong southerly winds 
are added, and freshes withheld, the height of the bores will be increased. 
It must be remembered, that the height of the bore, is actuated by the peculiar 
form of the sands, and the direction, and set of the tides, in any particular reach 
* During the inundation in September, 1823, the low water stood at eighteen 
feet six inches, the tide having ebbed only fifteen inches on that day. The differ- 
ence between this low water, and the high water (neap tides in February, viz. eight 
feet,) is ten feet six inches ! ! 
+ Except very rarely — In twenty-two years, I have known but three instances. 
Agreeably to the statement of load causes which accelerate or depress the tides, it 
will be obvious, that during the North-east monsoon, if the winds which blow the 
waters down the Bay, be more than usually moderate, and the moon’s parallax be 
high, there may be a high tide, and with it a bore ; and this, agreeably to the third 
local cause, will happen at uight. These night bores are particularly dangerous, as 
they are very rare, and, consequently, unexpected. They may be guarded against, 
by always considering it possible for them to occur during the North-east monsoon 
at night, upon a high parallax of the moon. Agreeably to the same local cause, it 
is fortunate that the bores at night, during the South-west monsoon, are not so 
high as during the day. 
