The S.W. monsoon, which prevails from April to October, blows against the northern part of the west coast of both Peninsulas, -and these conse quently, in some measure, participate in the rainy climate which characterizes -the eastern shore of the Bay of Bengal during this monsoon. Further south it is broken by the mountain belt of Sumatra, so that, in the Straits, land and sea breezes generally prevail in the vicinity of the coasts, and an equable climate is experienced. The Sumatra sides of the Straits, and the southern portion of the Peninsula, at night are exposed to occasional sudden squalls from the S.W. accom panied by lightning and heavy rains, called Snma trans. North-westers are also experienced, but more rarely. They occur chiefly in the northern part of the Straits as far as the Arroas, but some times blow right through them to the Carimons. During this monsoon the east coast of the Penin sula, having a leeward exposure, and being, for the greater part of its length, protected by the double wall of the Sumatran and Peninsular ranges, is perfectly sheltered, and dry weather prevails.
The Aravalli mountains extend from IIansi and Dehli to Gujerat. The Vindhya chain stretches across the centre of Hindustan, front the Gulf of Cambay to the Ganges, and is three to four thousand feet high.
A peninsular chain, called the Western Ghats, extends from Cape Comorin to the Tapti river, for upwards of 900 miles running parallel to the coast hne, and perpendicular to the direction of the monsoons. This chain divides the Peninsula into two distinct climates, of a narrow western oue in Malabar and the Konkan, and a broad eastern one, in which are the Karnatic, _Mysore, h. ud the Dekhan, traversed by all the peninsular nvers.
The Travancore mountains present a striking analogy to the island of Ceylon. They are loftiest at the extreme north of the district, where they stretch east and west for sixty or seventy miles, separating the districts of Dindigul and Madura. Notwithstanding the perennial humidity, the rain fall at Courtallum is only 40 inches ; on the hills around, however, it is doubtless much greater. The Pulney or Palnai mountains west of Dindigul, the Animallay south of Cohnbatore, the Sheva gherry mountains south-west of Madura, and the ranges near Courtallurn, are all well known. The remarkable palm, Bentinckia, so common on its mountains, is, however, not known in Ceylon. The other palms are Caryota urens, an Areca., Phcenix. farinifera, and one or .two . species of Calamus.
To the north of Cohnbatore the peninsular chain rises abruptly to 8000 feet, as the Neilgherry range, and continues northward as the mountains of Coorg. The rainfall, which is great on the
western coast, is less on the Neilgherries, being 100 inches at Dodabetta, and 46 inches at Ootaca mund. Further north, in the Nagar 'district of Mysore, there•are many rounded or talle-toppcd hills 4000 to 5000 feet high, often cultivated to that height, and rising in some places to upwards of 6000 feet. The climate of the western part is very humid, and particularly so at the town of Nagar or Bednore, 4000 feet high, on a spur of the western chain, where inclement rain is said to last for nine months.
The S.W. monsOoti domes from the southern ocean, and is loaded with vapour. It strikes on the W. coast of India, passes over the plains of Bengal, and strikes on the Khassya mountains and the whole length of the Himalaya, discharging itself in heavy rains. From April till August it blows from the east of south, in August S.S.E., and in September more easterly, lowering the tem perature of Bengal and of the northern plains, though the plains of tbe Panjab continue exces sively heated.
From the vernal till the autumnal equinox, the heat of a great part of India continues great ; bui after the autumnal equinox the great rnass of tht Himalaya becomes intensely cold; and 'the plaire of India generally become cool. Where the north east monsoon prevails, it is everywhere a land wind, except on the east coast of the Karnatie and in the Malayan Peninsula. In Malaya it blow; over a great extent of sea, and is tlirefore very rainy ; but at the Karnatic the width of sea is not great, so that the rainfall, though well marked, is less, and terminates leng before the end of tht monsoon, probably from the wind acquiring a more directly southerly direction, after the sun has reached the southern tropic.
The rainfall varies prodigiously in different parts of India, from ahnost none to six hundred inches ; but the quantity affords no direct criterion of the humidity of any climate, for the atmosphere may be saturated with moisture withoUt any precipita tion taking place. Thus, while in Sikkim 1° for 300 feet is the proportion for elevations below 7000 feet, on the Neilgherry Hills it is about 1° for 340 feet, in Khassya 1° for :380 feet ; and the elevations of Nagpur and Ambala produce no perceptible diminution in their mean temperature, which is as great as that which would normally be assigned to theni were they at the level of the sea.