6 H. F. Blanford— TAe Theory of the Winter [No. 1, 



On comparing these tables with those for the summer monsoon, 

 at the same stations, the relative greater frequency of calms, more 

 especially in the Punjab and the Gangetic plains, the inferior steadiness 

 of the wind in the prevailing quarter, and the very low absolute rate 

 of its movement are strikingly apparent. The highest rates of move- 

 ment are in Western India, as are also those of the summer winds, but 

 the former vary from less than half to less than two-thirds of the latter, 

 and the directions are much more variable. 



It is further to be noticed that, while, at most stations, there is one 

 direction of decided maximum, with some oscillation on either side 

 (this being the local direction of the winter monsoon), at stations in the 

 Punjab and the adjacent parts of the Gangetic plain, and also at Jhansi, 

 Jubbulpore, Chikalda, Mount Abu, and Kurrachee, there is a distinct 

 secondary maximum from an opposite quarter ; and, at Mount Abu, 

 Neemuch, and Bickaneer, a certain absolute preponderance of southerly 

 winds. These are the winds which interrupt the winter monsoon and 

 bring up the vapour that is condensed on the Himalaya as snow, and 

 on the plains of IS'orthern India as the winter rains of that region. 



In fact, not only is the barometric gradient which characterizes 

 the winter monsoon less highly inclined than that of the opposite season, 

 and the vertical height to which it prevails (the elevation of the neutral 

 plane) considerably less, but it is more frequently reversed, and espe- 

 cially so in January and February ; and, as a temporary phenomenon, 

 barometric minima, with the usual vortical systems of winds, occasionally 

 appear in Northern India. On such occasions, rain almost invariably 

 follows, beginning generally over the mountains that hem in the Pun- 

 jab, and on the plains at their foot, and thence extending to the east 

 and south-east ; while the barometric depression moves eastward, and 

 cold westerly winds, bringing fine weather and a wave of high baro- 

 metric pressure, follow up in the rear. 



In the majority of cases the history of which has hitherto been 

 traced out, the barometric minimum first appeared, and was apparently 

 formed in some part of the great north-western plain, most frequently 

 in the Punjab or Upper Sind ; but, in some cases, in Western Raj- 

 putana. Mr. F. Chambers has put forward the suggestion* that these 

 minima travel hither from regions further west, from the plateau of 

 Beloochistan or the still loftier mountain- tract of Afghanistan ; but this 

 seems to be a misapprehension. We have, indeed, no observatory in 

 Afghanistan, and it may be long before any systematic observation is 

 possible in that interesting, but turbulent, country. But an observatory 

 has existed for some years past at Quetta, and, although its elevation is 

 * Nature, vol. xxiii, p. 400. 



