566 
MR. H. P. BLANFORD ON THE WINDS OE NORTHERN INDIA. 
of AfFghanistan, and affords a passage to the winds from the west and north-west. On 
the north, at a distance of 24 miles, the hills of the Salt range, rising to 4600 feet, 
advance to the river, which here issues from the range and affords a passage to winds 
from between north and north-east ; while to the east and south the great unbroken 
plain of the five rivers stretches away in the direction of Lahore and Mooltan. 
The wind-registers of these stations extend over a period of a little more than three 
years. For three months at Lahore and one month at Mooltan only two years’ obser- 
vations are obtainable ; so that the data are less complete than those for other parts of 
our area, and, perhaps in consequence, they exhibit greater irregularities*. The obser- 
vations are those of the daytime only, viz. at the hours of 10 a.m. and 4 p.m., which are 
also those of the Gangetic-valley stations and of the Central Provinces. 
Beginning with Bawul Pindee, we find a general predominance of west winds, the 
annual proportion of which is 42 per cent, of the observations. East winds are rather 
more than half as numerous, and amount to 24 per cent. Winds from the north-east 
(4 per cent.) are the least frequent, and those from the remaining quarters in no case 
much exceed 7 per cent. The prevailing directions are undoubtedly mainly determined 
by the trend of the hills to the north of the plateau, and that of the Peshawur valley 
beyond the Indus. East winds attain their maximum, and west winds their minimum, 
in July. The latter are chiefly predominant from October to May, and the former are 
least frequent in November. In this latter month south-west winds are almost as 
frequent as those from the west, while in August south-east winds attain their maximum 
frequency, still subordinate in importance to those from the two dominant quarters. 
An annual rotation of the winds is slightly, but unmistakably, indicated by the Table. 
From April to July the veering is by north-west and north to east ; and from July to 
December through south-east, south, and south-west to west. 
The geographical position of Dera Ishmail Khan, under the lee of the Sulaiman 
range (trending from north to south), and at a distance from the Himalaya, determines 
a very different system of wind-currents. Here north-east winds predominate on the 
average of the year, amounting to 26 per cent., and west winds (5 per cent.) are least 
numerous. Winds from the east and south-east amount in each case to 15 per cent., 
and those from the remaining four points to between 9 and 11 per cent. In the cold- 
weather months, i. e. from November to April, west, north-west, and north winds are 
at their maximum, always subordinate, however, to those from north-east ; while from 
* I cannot but tbink that they are, to a considerable extent, vitiated by another cause, viz. the omission to 
record calms. Dr. Neil, who superintends the Punjab registers, assures me, indeed, that absolute calms are 
of rare occurrence in the Punjab ; but I must confess I cannot think that Lahore, for instance, differs in this 
respect so greatly from Roorkee and Agra as the registers seem to show ; and since it is clear that the regis- 
tration of calms at the Punjab stations has been uniformly neglected, the position of the wind-vane being always 
recorded as a wind-direction, some doubt must still attach to the probable frequency of calms in this region. 
Since writing the above, I have been informed by Dr. Calthrop that calms are very common in all parts of 
the Punjab. 
