50 0. Little — On two remarhable rain-bursts in Bengal. [No. 2. 



year recurved over Central India and in the latter year they did 

 not. 



And so it appears to me that this matter of the motion of cyclonic 

 storms over Northern India is one urgently requiring explanation, and 

 tliat so long as it is unknown in what direction a storm wull move in the 

 immediate future so long will the distribution of rainfall he a subject 

 of speculation only. So great a difference as we find between the 

 directions of motion of storms in the four periods of the past monsoon 

 season must he due to -well-defined causes which it must be possible to 

 determine. The only point on which I feel any certainty is that these 

 causes will not be determined by ground level observations. To me it 

 appears much more likely that they are connected with overhead condi- 

 tions, and the past season indicates that the cause may be found in an 

 overhead current from the west, that is in its height and strength. This 

 current is the main current over Northern India during the cold season 

 and the early part of the hot season. It retreats upwards with the 

 approach of the monsoon season and my opinion is that monsoon con- 

 ditions cannot be established in Northern India so long as its strength 

 is unimpaired. 



The only effects which I am aware of as giving some indication of 

 the strength of that current late in the season are the occurrence of late 

 snowfall in the hills, and of late nor'westers in Bengal such as were 

 experienced in June of last year. It is well known that for some years 

 late snowfall in the hills has been put forward as indicating the late 

 arrival of the monsoon, but I am not aware that there has been any 

 connection established between the snowfall and the strength of the 

 westerly overhead current. The reason for this doubtless is the great 

 difficulty always experienced in any attempt to investigate the higher 

 levels of the atmosphere — a difficulty which is not to any extent removed 

 by the establishment of observatories on ranges of high hills. It has 

 come to be recognised by meteorologists that a high level observatory 

 must be placed on the top of an isolated peak; otherwise the local 

 irregularities of the ground, such as the spurs and valleys of the 

 Himalayas, cause deviations in the record and the result is misleading. 



I have divided the monsoon season of 1902 into four periods — June 

 30th being the division between the first and second and August 11th 

 between the second and third of these periods — and I will now state 

 generally the line of advance of depressions from the Bay of Bengal 

 during these periods. 



Period A. 



In May a depression entered Burma, moving in a north-easterly 

 direction, the usual one at that time of the year. In June there was at 



