310 Journal of the Asiatic Society of Bengal. { Aug.-Sept., 1913. 
expanded lower layer, and the cold denser air above. Usually 
the tendency to large scale vertical currents is checked by a 
low vertical barometric gradient and by the fact that the air 
currents of the upper and lower atmosphere are moving fairly 
rapidly but in opposite directions. Anything, therefore, that 
would alter the gradient or reduce the speed of the winds 
beginning to flatten out, with the south wind, suddenly de- 
ected upwards, produces an aspirating effect which is shown by 
the dense clouds of dust usually associated with the first cloud. 
Nor a CyYcLone But Aan OBLIQUE AiR Sir. 
from the SSE usually. It forces its way up into a northerly 
air-current. Being a com paratively narrow bank it rapidly 
acquires the new velocity added to its own and their component 
is roughly eastward. 
f this proves ultimately to be the correct explanation of 
the transverse motion two important corollaries follow e 
first place it is evident that this motion is not an evidence of 
any cyclonic motion and the storm we see is not a mild typhoon, 
rently favourable symptoms. But it is exceedingly seldom 
that any hail falls. The absence of a large eddy seems sufti- 
ciently to explain this, and in its turn it supports the above 
theory of the cloud motion. 
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Mo I dns Ml 
