4 H. F. Blanford— r//c Theory of the Winter [No. 1, 



Sea-level Equivalents of AtmosjpJieric Pressure on the Punjab and 



Gangetic Plains. 



November. December. January. Febrnary. 

 ins. ins. ins. ins. 



Peshawar 30098 30174 30161 30-115 



Lahore -023 -097 '084 "029 



Delhi -017 -089 '076 '020 



Lucknow -008 "078 "062 '006 



Patna 29-995 -066 '060 -001 



Purneah '966 -028 '036 29-977 



Equivalents at 7,000 feet of Atmospheric Pressure at Stations on the outer 



Himalaya. 



November. December. January. February, 

 ins. ins. ins. ins. 



Darjeeling 23-404 23-380 23-339 23-320 



Chakrata "360 '340 '305 -281 



Murree '356 '332 '302 -^68 



It was shewn also in a paper on the winds of Northern India,* and 

 in the Indian Meteorologists^ Vade Mecum,^ that, as between the 

 Himalaya and Ceylon, the plane of neutral pressure, in January and 

 February, is at a lower level than 7,000 feet ; but not in the months 

 of November and December ; at least as an average condition. To this 

 point, which is important, I shall presently return. 



These facts of the pressure- distribution prepare us then to expect 

 that which our wind-registers shew, viz., that the winter monsoon is a 

 much shallower, weaker, and more unsteady current than its correlative 

 of the summer season. On the plains, the air is very calm in the Pun- 

 jab ; and, to the south and south-east, flows as a very gentle current, 

 chiefly a day wind, drifting from the N. W. down the Gangetic plain ; 

 from north or N. E., and somewhat stronger, across the Central Indian 

 plateau and the Satpuras ; and from north or N. N. W. in Lower 

 Bengal ; then turning to N. E. or E. in the northern part of the penin- 

 sula, while, down the Bay of Bengal, it is pretty steady as the well- 

 known N. E. monsoon. It turns, therefore, in an anticy clonic curve 

 around the seat of maximum pressure in North Western India. Its rate 

 of movement, its comparative steadiness, and its mean direction may be 

 estimated from the following tables : — 



* Phil. Trans, vol. 164, p. 563. 

 t Page 175. 



