apparently the chief cause of the rise and exundation of the Nile.

The passage occurs lib. vi. 712.

Nilus in æstatem crescit, campisque redundat,

Unicus in terris, Ægypti totius amnis;

Is rigat Egyptum medium per sæpe calorem,
Aut, quia sunt æstate aquilones ostia contra,
Anni, tempore eo, qui Etesia esse ferumtur;
Et, contra fluvium flantes, remorantur; et, andas
Cogentes surgus, replent, coguntque manere.
Nam, dubio procul, hæc advorso flabra feruntur
Flumine, quæ gelidis ab stellis axis aguntur:
Ille ex æstiferâ parte venit amnis, ab Austro
Inter nigra virûm percorto secla colore
Exoriens penitus mediâ ab regione diei.

The NILE now calls us, pride of EGYPT's plains;
Sole stream on earth its bound'ries that o'erflows
Punctual, and scatters plenty. When the year
Now glows with perfect summer, leaps its tide
Broad o'er the champaign, for the north-wind now,
Th' ETESIAN BREEZE, against its mouth direct
Blows with perpetual winnow; every surge
Hence loiters slow, the total currents swells,
And wave o'er wave its loftiest bank surmounts.
For that the fix'd monsoon that now prevails,
Flows from the cold stars of the northern pole
None e'er can doubt; while rolls the Nile adverse
Full from the south, from realms of torrid heat,
Haunts of the ETHIOP tribes; yet far beyond
Fish bubbling, distant, o'er the burning line.

3. Tropical Land-wind.

Good.

The island of Ceylon, which lies to the southward of the Coro. mandel coast, and where the peninsula becomes extremely narrow, partakes of both monsoons, but principally of the S. W. The wind immediately on the coast, at the commencement of this monsoon, takes nearly the same direction as the coast itself. From the latitude of 9 to 13 degrees, the coast lies nearly N. N. E. and S. S. W. and from the latitude of 15 degrees to the head of the gulf called Balascore Roads, it runs almost N. E. and S. W. The S. W. monsoon therefore on this coast blows at first along shore, from which cause it is called the Long Shore Wind. The nature of the soil on the coast probably contributes to give it this direc

tion; for the soil being, in some respects, like the Gulf of Guinea on the coast of Africa, low and sandy, the air near the earth must consequently be much rarefied under almost a vertical sun, and the denser air, coming across the Indian Ocean or the Gulf of Sind, will follow that direction on the coast to fill up the vacuum. But these winds continue only to the end of May or the beginning of June, when the sun being neer the summer solstice, the hot land wind on the coast of Coromandel commences, and continues about six weeks. To understand the causes of this sudden change, we must again advert to the geography of the country, and consider the state of the atmosphere at this period on the two coasts.

The southern part of the peninsula, from the latitude of 16 degrees to Cape Comorin, may be divided longitudinally into three parts, beginning at Madras, which is situated in the longitude of 80° 28′ 45′′ E. About two degrees to the westward of that meri. dian is a range of mountains, forming the eastern boundary of the Valley of Baramaul, where the high land of Mysore commences, commonly called the Ballagat, or country above the Passes. This high or table land of Mysore rises at least 2,000 feet above the coast of Coromandel, and runs through the peninsula from N. to S. nearly in the longitude of 78 degrees. Two degrees farther to the westward is another range of mountains, which may be considered as the boundary of the Malabar coast; and the country situated between these two meridians, from 76 to 78 degrees, is properly the country of Mysore. With this sketch of the map of the country before us, and with a recollection of the first principle of this hypothesis, it will not be difficult to account for the hot land wind prevailing in the Carnatic during the months of May and June.

The sun's declination in the month of May is between 15 and 22 degrees N.; he will therefore before the end of this month have been vertical over all these countries, and consequently have pro. duced a considerable degree of heat in the Carnatic; but at the same time the double range of mountains to the westward will have arrested the clouds brought thither by the S. W. monsoon, and made them precipitate their contents both on the Malabar coast and in the Mysore country. The principal point of rarefaction then, at this season, will be the Carnatic, which may, as usual, be considered as the heated room, and the nearest cold body of

air will come from the table land of Mysore to restore the equilibrium.

In the Carnatic, during the months of May and June, the thermometer of Farenheit in the shade is generally at 90 or even 100 degrees and upwards, whilst near the mountains the same kind of thermometer will not be more than 70 or 80 degrees at the utmost. The current of the air then will move from the mountains across the Carnatic towards the coast of Coromandel, and of course produce the hot land winds, but they are severely felt only on the east side of the Carnatic, at a distance from the mountains: at Amboor, and even at Vellore, which are situated near them, those winds are neither extremely hot, nor of long duration; and in the narrow part of the peninsula, in the beautiful little province of Coimbatore, although so far to the southward, in consequence of their vicinity to the hills, the inhabitants are never incommoded by land winds.

This rarefaction in the Carnatic, and the current of air which comes from the Ballagat Mountains, and blows from the W. to the E. to fill up the vacuum, are sufficiently strong inland to counteract the effects of the monsoon in this part of the peninsula; but the westerly wind soon loses its effect on coming to the coast, for it never extends above one or two leagues out to sea, where the S. W. monsoon blows incessantly at this season of the year.

But within a month after the summer solstice, the current of the S. W. monsoon begins to slacken, when the regular land and sea winds again commence upon the coast of Coromandel, and continue with slight variations for a month or six weeks. Towards the end of August, as the sun approaches the line, the heat in Asia and the cold in Africa begin to abate; consequently the monsoon daily becomes more faint, and like the slack water between the flood and ebb tides, the air in the Gulf of Bengal has little motion: frequently it moves about: in eddies, and after it has fluctuated between the two monsoons for three weeks, sometimes almost a month, being attended with sqnalls from different quarters, the N. E. wind at length prevails, and like the change of tides, moves at first with considerable rapidity. But the tremendous gales, or rather hurricanes, which sometimes blow in the gulf at this season, and bear down every thing before them, seldom happen precisely at the beginning of the monsoon, nor does it appear that they are the

effect of a current of air like the monsoon, blowing constantly from the same quarter for several months, but rather resemble whirlwinds, which proceed 'principally from some sudden change in the upper regions of the atmosphere, and which, though extremely violent, are merely local and temporary. But before we conclude the account of the S. W. monsoon in Hindustan, it may be proper to observe, that this monsoon brings the violent rains into the provinces of Bengal and Bahar, which generally begin at Calcutta about the middle of June, two months after their commencement to the southward of the gulf.

4. Khumseen.

[Capper.

The Arabian and Persian gulfs are not only separated by Arabia, but the major part of the former is within the tropic, whilst the northern part of it, like the whole of the Gulf of Persia, from Muscat to Bossora, is situated beyond the tropic. In comparing the winds of these gulfs, therefore, we must make a distinction between the northern and southern division of the Arabian Gulf. From the entrance of the Straights of Babelmandel to the city of Yambo, the S. W. monsoon prevails at the same time as it does in the Gulf of Sind, that is from April to September. But from the 15th of May to the beginning of August, the S.W. monsoon is extended, or rather elongated, from Yambo to Suez, notwithstanding the latter is almost eight degrees beyond the tropic. This wind is called by the Arabs the Khumseen (fifty), being supposed by them to precede the overflowing of the Nile about fifty days*.

The Khumseen wind blows in the northern part of the Arabian Gulf, as far as the sea-coast of the Delta.

It is very well known that the soil of Upper, and even of a part of Lower Egypt, on one side of the Arabian Gulf, and of Arabia Petrea and Arabia Deserta on the other, consists chiefly of rocks and sands. As the sun approaches towards the solstice, and from very obvious causes, for a month or six weeks aftewards, the atmosphere over those countries must be excessively rarefied; whilst this rarefaction continues to the northward, the air to the N. after the commencement of the rains, being infinitely more cold and dense, will be impelled forward towards the N. to re

* The reader will hence observe that the Khumseen is synonymous with the prodromi, or breezes that precede and introduce the Etesian wind. EDITOR.

store the equilibrium, and consequently produce the Khumseen wind, which for the same reason will precede the overflowing of the Nile, and begin first near the principal point of rarefaction. But as the sun approaches again towards the autumnal equinox, the earth to the northward becomes cool, the Khumseen ceases to blow, the river begins to fall, and the N.W. wind again com mences, and continues to blow all the rest of the year.

It is true, as was before mentioned, that almost the same winds prevailed at the same season in the Gulf of Persia as in the northern part of the Arabian Gulf; but the eastern shore of the former being covered with both hills and forests, the Khumseen will nei ther begin quite so soon in the Gulf of Persia as in Upper Egypt or Arabia, nor even continue to blow there with equal strength. [Id.

5. Sirocco.

THIS peculiar wind, sometimes written Scirocco and Sciloco, proceeds in the south part of Italy and Sicily from the S. E.; it blows occasionally with great force in the month of July, but sometimes commences faintly about the summer solstice.

This wind resembles the Khumseen, and the land wind in all tropical countries, not only in its appearance and effects, but likewise in the time of its commencement. It must be allowed, that it does not blow in the southern part of Europe without intermission for forty or fifty days, nor does it continue quite so long as those winds do in Asia and Africa, but it is extremely oppressive during the time it lasts, even to the Sicilians and Neapolitans.

According to Mr. Brydone, the inhabitants of Palermo do not understand in what manner to guard against its effects so well as the natives of Hindustan; for the Sicilians content themselves with merely shutting their windows, and where there are no shutters they hang up a wet blanket instead of them, which must be very soon dried; but the wiser Indian puts a curtain of grass before the window or door, which he constantly wets on the side exposed to the wind, and thus by keeping up a constant evaporation, the air which passes into the room is rendered perfectly cool.

Mr. Kirwan observes, that the degree of cold, produced by evaporation when the air is warmer than the evaporating surface,