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XVII. The Winds of Northern India , in relation to the Temperature and Vapour- 
constituent of the Atmosphere. By Henry F. Blanford, F.G.S., Meteorological 
Beporter to the Government of Bengal. Communicated by Major-General 
Strachey, B.F., C.S.I., F.B.S. 
Received May 15, 1873 —Read February 26, 1874. 
Contents. 
Page 
Introduction 563 
Past I. — Description op the Winds. 
The Punjab 565 
The Gangetic Plain 568 
Plateau of Rajpootana and Bundelkund . . 571 
Central India 573 
Western Bengal and Orissa 574 
The Gangetic Delta 576 
Assam 578 
The Arakan Coast 580 * 
Summary 581 
Part II. — Relations op the Winds to other 
Elements of Climate. 
Temperature. Horizontal and vertical dis- 
tribution 585 
Page 
Yapour-tension, Humidity and Rainfall . . 594 
Atmospheric Pressure. Horizontal and 
vertical distribution 602 
Certain effects of the Winds 613 
General Summary 617 
Appendix. 
On the Cyclones of tho Bay of Bengal .... 623 
Tables. 
Wind-directions &c 629 
Temperature 643 
Yapour-tension 645 
Humidity 646 
Rainfall 647 
Atmospheric pressure 651 
Description op Plates 653 
INTRODUCTION. 
It is my object in this paper to describe the normal wind-currents of Northern India 
and their annual variation, and to trace out their origin and causes, in so far as these 
can be discovered in the local physical changes of the atmosphere. For this kind of 
inquiry India offers many peculiar advantages. At opposite seasons of the year it 
exhibits an almost complete reversal -of the wind-system and of the meteorological 
conditions depending on it or on which it depends ; its almost complete seclusion, in 
a meteorological point of view, from the remainder of the Asiatic Continent, by the 
great mountain-chain along its northern border, simplifies, to a degree almost unexam- 
pled elsewhere, the conditions to be contrasted by limiting them to those of the region 
itself and of the seas around; while it presents in its different parts extreme modifica- 
tions of climate and geographical feature. In its hill-stations it affords the means of 
gauging the condition of the atmosphere at permanent observatories up to a height of 
more than 8000 feet, and in the loftier peaks and ridges of the Himalaya, at temporary 
MDCCCL5XIV. 4 G 
