1904.] 0. Little — The recent excessive heat in Bengal. 7 



bably in all cases, due to local disturbances if the cool weather be of 

 brief duration, and to the direction of the surface air- currents in cases 

 where as lately in North-Western India, the cool weather continues for 

 weeks. The cause of prolonged depression of temperatures, being sur- 

 face winds, is to be found in the record of the observatories. But high 

 temperature cannot in the same way be accounted for by surface winds 

 nor by surface conditions. For if an examination of the meteorological 

 records be made, it will be found that, with high temperature, there have 

 in the past co-existed an infinite variety of surface conditions, pressure 

 sometimes below the normal, winds sometimes in one direction sometimes 

 in another, humidity high and humidity low. There must, of course, be 

 an absence of cloud. A sufficient test of the accuracy of the above dif- 

 ference between high and low temperature conditions may be given from 

 weather forecasting experience. Meteorologists have hitherto failed to 

 find any indication of coming high temperature, and they have been 

 equally unable to say for what time it will continue, whereas low tem- 

 perature is rapidly seen advancing over an area of observation such as 

 the United States. Anyone who follows the progress of meteorology 

 in the United States will remember how accurate are the forecasts of 

 advancing " frosts," and readers of the daily papers will remember the 

 severe criticism to which the Head of the United States Weather Bureau 

 was subject, two years ago, when he attempted to forecast the continu- 

 ance of the excessive heat in New York and other parts of America. 

 According to telegrams which reached this country the opinion of the 

 American press was that the Weather Bureau could not have been in 

 possession of the information on which such a forecast could, with any 

 possibility of success, be based. 



In such matters it is easy to be wise after the event, and it is equally 

 easy to suggest causes which may or may not have contributed towards 

 the event. Where the causes are not indicated by the meteorological 

 record the only check upon an alert imagination is ordinary common- 

 sense or a knowledge of physical laws. I think I may safely infer from 

 past experience without unduly straining my powers of imagination or 

 the faith of the members of this Society, that to explain the excessive 

 heat in Bengal during April and May something more than ground level 

 obsicrvations are required. If information regarding the lower layers of 

 the atmosphere is not sufficient, there is only one opening to progress. 

 We must find out more about the upper layers, and my chief object in 

 offering this paper for publication is to put on record a few observations 

 which I have made during the past season on cloud movement and 

 thunderstorms, as they have appeared to a resident of the European 

 quarter of Calcutta, In one respect these observations appear to me to 



