374 MR. S. A. HILL ON THE WINDS OF NORTHERN INDIA, AND THEIR 
Table XIX.—Pressure Differences over the Gangetic Valley in Thousandths of an 
Inch. 
Year. 
A jmere — 
Chakra ta. 
Sutna—Rinikhet. 
January. 
May. 
July. 
October. 
January. 
May. 
July. 
October. 
1877 . . 
+ 137 
+ 199 
+ 153 
+ 61 
+ 64 
+ 142 
+ 52 
+ 79 
1879 . . 
+ 149 
+ 179 
+ 106 
+ 146 
+ 90 
+ 59 
-25 
J- 31 
1880 . . 
+ 131 
+ 156 
+ 54 
+ 132 
+ 76 
+ 160 
-18 
+ 101 
1883 . . 
+ 186 
+ 143 
+ 41 
+ 142 
+ 103 
+ 166 
-40 
+ 58 
1884 . . 
+ 156 
+ 188 
+ 70 
+ 87 
+ 91 
+ 144 
-59 
+ 62 
Year. 
Hazaribagh- 
—Darjiling. 
Mean of the three Pairs of Stations. 
January. 
May. 
July. 
October. 
January. 
May. 
J uly. 
October. 
1877 . . 
+ 21 
+ 109 
-21 
+ 31 
+ 74 
+ 150 
+ 61 
+ 57 
1879 . . 
+ 86 
+ 116 
-48 
+ 18 
+ 109 
+ 118 
+ 11 
+ 65 
1880 . . 
+ 60 
+ 66 
-73 
+ 21 
+ 89 
+ 127 
+ 12 
+ 85 
1883 . . 
+ 81 
+ 148 
-60 
+ 51 
+ 123 
+ 152 
-20 
+ 84 
1884 . . 
+ 162 
+ 142 
-88 
-51 
+ 136 
+ 158 
-26 
+ 33 
On comparing this Table with the figures given above for the variations of rainfall, 
it will he seen that, in the worst years, 1877 and 1880, the mean gradients for 
January were least, indicating the probable existence, for a considerable number of 
days in the month, of moist south-easterly currents, bringing the snowfall, which, 
according to Mr. Blanford’s theory, was the cause of the subsequent drought. 
These moist winds were observed in January, 1877, on the plains; but in 1880, as 
Mr. Blanford has pointed out in the paper above quoted, they were confined chiefly 
to the higher valleys and slopes of the Himalaya. In May, the variations of the 
pressure differences are less evidently connected by any rule, and in July there 
apparently is in the mean of the three pairs of stations a nearly uniform decrease in 
the gradients for westerly winds or an increase in those for easterly ones during the 
eight years from 1877 to 1884. 
It does not seem right, however, to group the Hazaribagh-Darjiling pair with the 
others, as the character of the rainfall of any season in Bengal is usually different 
from and often opposite to that which obtains in Upper India. Thus, in 1883, in 
which the gradients over West Bengal appeared rather favourable for rainy winds, 
the defect of rainfall in that province was only 4 per cent., as against 17 per cent, 
in the upper provinces, and this small defect may possibly be explicable by other 
causes;* whilst in 1880, during which the gradient between Hazaribagh and Dar- 
* For example, tlie diminished absolute humidity of the air, owing to the temperature being below 
the average. The mean temperature of the whole of India in 1883 was 0'48° below the average, and the 
vapour tension was ’013 inch in defect, 
