i888.] occurred at Dacca on April 7th, 1888. 197 



in any way differing from the general atmospheric oscillation which was 

 taking place over Bengal, and no indication of any kind was given of 

 the possible formation of any violent storm over this area. So far then 

 as the pressure indications go, it would appear that the extremely 

 feeble comparatively low pressure area which on the 6th was over 

 Chutia Nagpur and West Bengal was advancing slowly in a north- 

 easterly or easterly direction, and it is certain that the pressure at 

 some of the stations in the centre of the Province, particularly at 

 Kishnagar or between that station and Berhampore, was distinctly low. 

 At Kishnagar indeed the fall of pressure in the 24 hours preceding 

 10 A. M. of the 7th was 0'074 inch, while at Berhampore it was 

 0072 inch. 



A glance at PL XXV., representing the meteorology of this day, 

 will again shew the very marked contrasts of temperature and humidity 

 which existed over the centre and north of the Province, and particu- 

 larly in North and Central Bengal, where high temperature with low 

 humidity and low temperature with high humidity existed within a few 

 miles of each other. Thus at 10 A. m. at Dinagepore temperature was 

 99"8° and humidity was 13 per cent., while at Rungpore, a few miles to 

 the east north-east, temperature was 88*4° and humidity 45 per cent. 

 At Nya Dumka temperature was 97*9° and humidity 13 per cent., and 

 at Berhampore, a few miles to the east, temperature was 90'4° and humi- 

 dity 63. It will, however, be noticed that this area of great contrasts of 

 temperature and humidity had advanced much further north than it was 

 on the 6th. In fact, when comparing the humidities and wind directions 

 at the various stations on the two days, it is seen that on the 7th the 

 moist southerly wind current had advanced rapidly over Central and 

 part of Korth Bengal, and had either forced back the dry westerly wind 

 before it, or had pushed its way under it, and thus on this day there is 

 no doubt that the moist current from the Bay of Bengal made its 

 influence felt as far as Berhampore, Rampore Beauleah, Bogra, Maldah, 

 and Rungpore, but that it had failed to reach as far north as Dinagepore. 

 This fluctuation in the area affected by these winds is unusually large 

 and well marked, but, as will be seen subsequently, the observations of 

 the 8th April shewed that this northerly advance of the moist southerly 

 winds was purely temporary, and by the morning of the 8th the moist 

 winds had been completely driven back to their former position. Such 

 large oscillations as these point most unmistakeably to a most disturbed 

 state of the atmosphere, and it will be remembered that, on the evening 

 of this day, the tornado at Dacca happened. 



The following table contains some of the principal meteorological 

 observations taken in Bengal on the morning of the Sth April :— - 

 26 



