370 MR. S. A. HILL OR THE WINDS OF NORTHERN INDIA, AND THEIR 
and Oudh—a region comprising between one-third and one-half of the plains of 
India—has varied from the average as follows : — 
Year:— 
1877. 
1878. 
1879. 
1880. 
1881. 
1882. 
1883. 
1884. 
Rainfall variation per cent. 
- 3.5 
-2 
+ 5 
-20 
+ 2 
+ 4 
-17 
+ 16 
These are the variations computed on the total rainfall of the year, w T hich averages 
31'26 inches. Owing to the opposition in sign of the variations for the winter and 
summer months, the summer rainfall alone would give larger departures from the 
average, the defect in 1877,* for example, being 55 instead of 35 per cent. The totals 
for the separate seasons are not given in the summaries! from which the above figures 
are taken ; but, as those of the summer nearly always vary in the same direction as 
the annual totals, the latter will suffice for our purpose, which for the present has 
reference only to direction and not to extent of variation. 
Leaving out of account the two years 1878 and 1881, for which the variations lie 
within the limits of possible error, and also 1882, the barometric data for which at one 
of the stations given below are incomplete, there remain five years of distinctly marked 
positive or negative variations in the rainfall. Table XVII. gives the observed 
pressures and day temperatures, for the four typical months of these years, at three 
stations on the outer Himalayas, and three others in a nearly parallel line on the 
plateau to the south of the Ganges valley ; and in Table XVIII. are given the com¬ 
puted pressures at an elevation of 10,000 feet. In making the computations for this 
Table, the same rates of temperature decrement have been assumed as in constructing 
the Table of normal values, though there is reason to believe, as above stated, that 
these rates may be different for dry and showery months of the winter and spring; 
but, then, we have at present no means of estimating exactly what the variations from 
month to month of this element of our calculations may be. Some of the apparently 
anomalous results worked out below would, doubtless, disappear if the true rates of 
decrement were known and used. 
* Owing to the heavy rainfall of the winter and spring months of 1877, the total rainfall of the 
N.W. Punjab that year was considerably over the average. 
f Near the end of the letter-press of each Annual Report on the Meteorology of India. 
