Generally, on the sea-coast, at the times when no steady monsoon is blowing, the wind blows from the (comparatively) cool sea to the heated land during the afternoon and evening; and from the (comparatively) cooled land to the warmer sea in the early morning before sunrise. These are called the land and sea breezes: at places like Madras, Bombay, and Colombo, the sea-breeze of the evening is looked forward to with longing during the intense heat of the day in the hot weather months.

§ 50. The Rainfall.-India in its various parts presents every extreme of climate in regard to humidity. The largest recorded rainfall of the world is that of Cherrapunji, a small station on the southern face of the Khasi Hills, where the average exceeds 500 inches per annum. In the deserts of the north-west of Rájputána, and the adjacent districts of Sind and the Punjab, it often happens that not a drop of rain falls in the year, and the average cannot be put at more than 3 or 4 inches per annum; and between these two extremes every variation of humidity is to be found.

The heavy tropical rains of the summer monsoon depend for their intensity, in various parts, on the course of the monsoon and the character of the surface over which it blows. We have seen that the winds of that monsoon reach the shores of India from the south-west, laden with the moist vapours of the Southern Seas. When a chain of mountains runs athwart their course a portion of the air is driven upwards, expands and cools, and so precipitates a part of its vapour in heavy rain. These conditions are most perfectly fulfilled in the case of the Khasi Hills; they also hold in the outer Himálayas, Sikkim, and the adjoining countries, the Yomas of Arakan and Pegu, and the Western Gháts. In all these regions the rainfall is prodigious. It diminishes rapidly in proportion to the increasing distance from the hills, but in each case there is a broad belt in which the rainfall exceeds 100 inches every year. These, then (as will be seen by reference to the accompanying

chart), are the regions of maximum rainfall-East and North-East Bengal, Lower Assam, Arakan, and Pegu, the west coast of the peninsula under the Western Ghats, and the west coast of Ceylon.

The summer monsoon, on striking the Himálayas north of Bengal, is deflected in a westerly direction; it sweeps along up the valley of the Ganges through Oudh, the NorthWest Provinces, and the Punjab; still precipitating its moisture in copious rain, the quantity of which diminishes gradually in its progress. That branch of the monsoon, too, that comes from the Arabian Sea has a great tract of country to pass over before it reaches the Punjab, and some mountain-ranges. Moreover, the great heat of the Punjab, Sind, and Rájputána prevents much condensation; hence these regions are those of minimum rainfall, especially in summer. The average annual rainfall of Lahore is only 18 inches; that of Rawalpindi, which is much nearer the Himalaya, about 30 inches; whilst that of Multán is only 6 inches.

The summer monsoon, after passing a range of hills (such, for instance, as the Western Gháts), has lost much of its moisture; and on descending into the hotter regions beyond becomes comparatively dry. Hence the lee side of such ranges is a region of comparatively small rainfall. Thus, the rainfall of Shillong, the head-quarters of the Assam Government, on the lee side of the rainy Khasi Hills, is not greater than that of Calcutta-about 60 inches; that of Poona, in the Bombay Deccan, just east of the Western Ghats, is only 26 inches; though not very far from Bombay, where the rainfall (being that of the rainy belt under the Gháts) is more than 70 inches. In Ceylon this phenomenon is even more strongly marked. Near Nuwara-eliya, at the summits of the mountains, there are valleys a few miles to the west which are deluged with the heaviest rain during the summer months, whilst the valleys a few miles to the east are almost cloudless.

In this way the east coast of Ceylon, and that of the

Peninsula (the Carnatic), get comparatively little of the summer rains. But towards the end of the summer monsoon, the heat of the Carnatic having thus become comparatively excessive, the monsoon-wind of the Bay of Bengal becomes deflected to the west, to this hot region; and thus. the rains of the Carnatic and eastern Ceylon come chiefly

in October and November. Until recently it was supposed that these rains were brought by the beginning of the north-east (the winter) monsoon; but it is now found that as the winter monsoon gradually becomes established further and further south, it brings dry weather to the Carnatic as elsewhere.

§ 51. Hot Weather Temperature.-If we except minor

local differences of temperature, due solely to differences of elevation, we shall find that broadly in the hot summer months, from March to June, the relative temperature of different parts of India is determined mainly by the distance from the cooling influence of the sea and the sea-breezes. In April and May the hottest part of India is Rájputána, with Indore, Bhopál, Barár, and the western part of Nágpur, which regions are all included within an isotherm of 90°. In June the region of maximum heat moves northward to the Punjab; where, allowing for differences of elevation, the average temperature of the day is hardly

below 100°. At this season the coolest part of the Empire is Burma, with portions of Assam, with an isotherm of 80°; and next come Lower Bengal, with the east and west coasts of the peninsula, under an isotherm of 85°.

§ 52. Temperature during the Rains.-With the setting in of the summer monsoon the temperature falls considerably in all those parts that are affected by it. The difference is most perceptible in those parts reached by the monsoon that were before hottest, as in Central India; but the Punjab and Sind are still the hottest parts, for there the rainfall is scanty. During September, the high latitude of the Punjab now removing it more from the

heating power of the sun, the region of maximum heat is transferred to the Carnatic and the east coast of Ceylon, where little rain has fallen.

§ 53. Temperature during the Cold Weather.-With the approach of the winter monsoon the temperature in the Punjab falls rapidly; and this province has a much colder winter than any other part of India, frosts being sometimes experienced. Indeed, in the cold weather (i.e. from the middle of November to the beginning of February) the general temperature depends mainly on the latitude, the heat increasing from the Punjab to Ceylon. In the an

nexed chart it will be observed that the isotherms for January are more or less parallel to the lines of latitude; Madras being hotter than Central India and Bombay, the latter hotter than Bengal and the North-West and Rájputána, and the Punjab colder than any.

§ 54. Storms and Storm-waves.-The hot-winds and dust-storms that occur in the drier regions of Northern India during the hot season have already been noticed. In Bengal, during the same season, violent thunderstorms, called nor'-westers, frequently happen in the afternoon and evening after a very hot morning. They derive their name from the fact that they usually approach Calcutta from the