Vol. IX, Nos. 8-9.] Nor’ westers and Monsoon Prediction. 307 
[N.S.] 
smallness of area of the nor’wester is an advantage from this 
point of view. In larger storms the cloud changes are slower 
and more widely diffused. Here they are rapid and concen- 
trated. One observer can therefore do the work that would 
otherwise require a dozen scattered over a prolonged storm 
ea. 
The proving or disproving of the theory tentatively sug- 
gested here is therefore a matter requiring small expense and 
little organization. It requires a single interested observer who 
registers what he sees and is sufficiently aaeniy to extend his 
observation over an adequate number of yea 
Sir J. Eviot’s RESEARCHES. 
As regards the barometric and wind changes, Sir John 
Eliot in his paper of 1876 shows that the conditions under 
which nor’ westers occur are an increase in the relative pres- 
sure oe the middle of the Bay, with its consequent of a dif- 
fused shallow low pressure over the Delta. This he conceives 
fo) oisture current of considerable 
depth from the south-west across the Bay towards the Arracan 
- his current c the flow of the upper northerly 
rent across Bengal, and before the moist current can be de- 
flected into the depression in Bengal a down-rush of cold air 
t m 
increase in pressure in the Bay is probably due to the south- 
west current and not vice versa, this may be accepted provi- 
sionally. He then goes on to show from meteorological statis- 
tics that the distinguishing feature of these storms is an actua 
rise in the barometer as they approach. Then, coincident with 
the greatest rise of the phenieer the temperature suddenly 
t 
nba rapidly and the wind reverses its direction from the south- 
t to the north-west. Afterwards there follows rain which 
may be small or large in amount. He ascribes these changes 
to the sudden displacement vertically downwards of a large 
body of air due to diminished pressure. In the words of 
modern aeronauts the tpt is caused by the vertical filling up 
of a large ‘‘hole’’ in the air. 
In his later paper on ‘‘ Anemographic observations recorded 
at Saugor Island from March 1880 to February 1904’’ (published 
in 1905), Sir John Eliot appears to connect the storms more 
closely with the normal hot weather depression which stretches 
from West Bengal through Chota Nagpur to Upper Sind or the 
North-West Punjab. The three air currents—from the Bay and 
down the Ganges and pert valleys—create a feeble 
cyclonic movement, and w the shallow depression ago 
towards north Bengal the™ Bay winds recurve to pass u 
