JOURNAL 



OF THE 



ASIATIC SOCIETY OF BENGAL. 



Part II.— NATURAL SCIENCE 

 No. I.— 1884. 



I. — The Theory of the Winter Rains of Northern India. — By Henry 

 F. Blanford, F. R. S., President^ Asiatic Society of Bengal, Meteo- 

 rological Reporter to the Government of India. 



[Eeceived and Kead Marcli 5th, 1884.] 



(With Plate I.) 



It has long been a commonplace of meteorological hand-books, 

 that the winter, or, as it is more frequently (but less accurately) termed, 

 the north-east monsoon, is due to a reversal of those conditions which, 

 in the summer season, set in movement a flow of air from equatorial 

 regions towards the plains of Southern and Eastern Asia. But, beyond 

 this general statement of fact, very little has been done towards working 

 out the physical characteristics of this familiar phenomenon of the 

 Indian winter ; and such vague conceptions as are implied in the popular 

 theory, leave entirely unexplained the well-known occurrence of rain, 

 about Christmas time, in Upper India ; a region, which, according to 

 that theory, should then be the seat of a barometric maximum, the fount 

 and source of the winter monsoon. 



Since the establishment of a Meteorological Department under the 

 Government of India, has rendered it possible to study the weather of 

 India as a whole, from day to day, some insight has been gained into 

 1 



