ME. H. E. BLANEOED ON THE WINDS OE NOETHEEN INDIA. 
577 
Of the four stations that I select for illustrating the wind-system of the delta, three 
(viz. Saugor Point, Calcutta, and Berhampore) are situated along a line from south to 
north parallel to its western border and at no great distance from it; the fourth 
(Dacca) lies 120 miles to the eastward of the last-named station, about equidistant from 
the sea and the eastern hill boundary of Tipperah. Berhampore, 160 miles from the 
coast, is 64 feet above sea-level, the other stations at various less altitudes. Saugor 
Point, at the entrance of the Hooghly estuary, is a mere marsh, protected by embank- 
ments from submergence at high water. 
As a consequence of the physical configuration of the country, nearly the whole of 
the lower stratum of air that sweeps over the delta is in transitu between the sea and 
the Gangetic plains to the westward. The Assam valley, owing to its narrowness and 
the abruptness of its junction with the broader Ganges valley, affords but an obstructed 
and tortuous passage to this stratum, and it is chiefly an upper current that, passing 
over the low hills of Tipperah and the Khasi and Jynteah hills to the north of these, 
makes its way to or from Upper Assam as the monsoon wind. 
The wind Table for Calcutta has been drawn up from the hourly observations of ten 
years, and, notwithstanding the roughness of the observations, represents the wind- 
system probably with as much accuracy as is attainable in the absence of self-registering 
instruments. The velocities are obtained from four years’ observations. For other 
stations, three years’ registers of observations recorded at six-hour intervals have been 
used. In two cases, viz. Berhampore and Saugor Island, the registration of calms has 
been neglected during the greater part of the period : the Saugor-Island Table is pro- 
bably scarcely affected by this omission ; but such is not the case at Berhampore, and I 
give therefore the register of one year in addition in which calms have been recorded. 
At Saugor Island south and south-west winds predominate greatly over those from 
any other quarter, amounting together to 52 per cent, on the average of the year. 
North-west and west winds and their opposites are least common, amounting to from 5 
to 8 per cent, respectively. At Calcutta south winds form 81 per cent, of the annual 
average, and there is a slight but decided preponderance of westerly over easterly 
components. At Berhampore the case is very different. The excess of south winds 
over those from any other quarter is but small ; and there is a difference of only 5 per 
cent, between them and south-west winds, which are here the least frequent. At Dacca, 
again, south winds preponderate, and south-east winds stand next in order, while easterly 
components slightly exceed the westerly. 
At all these stations the annual rotation of the wind is incompletely retrograde, and 
such as has already been described at Hazareebagh. The winter monsoon or land-wind 
sets in in October and becomes well established in November, with a mean direction 
which is nearly north at Dacca and Saugor Island, north-north-west at Calcutta, and 
north-west by north at Berhampore. At Saugor Island it blows pretty steadily during 
the three months November to January from a direction a few degrees east of north, 
and at Berhampore it is almost equally steady ; but at Calcutta and Dacca it backs 
