290 
I have taken from the meteorological report for 1878 the 
rainfall in a number of stations in illustration of the influence of 
season and the monsoons in different regions of India ; 1878 
seems to have been an exceptional year, with peculiar varia- 
tions from the ordinary conditions, for, whilst unusually dry in 
some, it was unusually wet in other districts. The general 
result was an average rainfall for the whole country registered, 
4*9 inches in excess of previous years. 
The following averages of a number of previous years are 
instructive. In Calcutta, for example, 65*80 inches fell, the 
greatest falls being in the months of. — June, IT 78; July, 
12*77; Aug., 13*96; Sept., 10*15. 
In Chittagong, the greatest falls were in, — June, 21*35; 
July, 2T93; Aug., 21*71; Sept., 14*05. The whole rainfall 
was 103*7. 
In Bombay, the whole rainfall was 74*20. The greatest 
was in, — June, 20*95; July, 24*27; Aug., 15*21; Sept., 
10*71. 
In Kurrachee the fall was 7*61. The greatest being in, — 
July, 2*97; Aug., 2*10; Sept., 0*81; Dec., 0*22; Jan., 0*67 ; 
Feb., 0*26. 
In Mangalore, on the west coast, in the full intensity of the 
south-west monsoon, the fall was 134 inches. The greatest 
falls were in: — June, 40*09; July, 37*68; Aug., 23*14; 
Sept., 11*70; Oct., 8*55. 
In Madras, 48*15 fell. The greatest falls were in, — Oct., 
10*73; Nov., 13*0; Dec., 4*99; Jan., 0*65, showing the 
influence of the wet north-east monsoon. 
In Tinnevelly, the fall was 28*16 in the whole year, greatest 
iu, — Oct. 6*25; Nov., 9*86; Dec., 2*63; Jan., 1*55. 
In Southern India at several stations, as, for example, 
Coimbatore, Bangalore, and others, both monsoons are felt, 
and a certain amount of rain is due to each. 
Irrigation. 
Though a great part of the continent of India is amply 
supplied with rain, there are extensive regions where the 
normal quantity is so small that it is insufficient to produce the 
crops that are necessary for the support of the population, and 
where, without the aid of artificial irrigation, the land would 
be sterile. This irrigation is effected by reservoirs, canals, 
and wells. In regions where the yearly rainfall is less than 
15 inches irrigation is always necessary; such are the arid 
zone in the north-west, including most part of the Punjab, 
the great desert tracts of the north-west, and in that known 
