over the Great Desert from India; and he appears through his whole life to have been a judicious and attentive observer. In situations such as he has experienced, much might have been attained by attention only: in this he has not failed; while he has added to it whatever the philosophy of his time could contribute to elucidate the subject. We much regret, however, that the observations of De Luc, De Saussure, and Sennebier, were unknown to him: these, with some later authors, would have greatly illustrated, and in some places have corrected, his theory. Our author's object is to elucidate the doctrines of Bacon, as further dilated by Dr. Halley. We will not stop to inquire where those 'germs' are to be found, in the works of the former, of almost every modern discovery,' because we know how easily hints are expanded into systems, and that an accidental conjecture is often magnified into the anticipation of a discovery. We will however admit that Bacon and Halley were well acquainted with the causes of the trade-winds, and of the monsoons; but we are equally certain that their system is wholly inapplicable to the whirlwinds, the irregular currents of the air in temperate climates, the harmattan, or the sirocco. So far, however, as their system went, colonel Capper has considerably improved it; and the body of meteorological facts, which he has collected in its support, will be of the highest importance to every philosophical inquirer, and reflect no little credit on his diligence and ingenuity. We need not enlarge on our author's judicious geographical distinctions, nor on the division of the different winds, which are chiefly important to those who peruse the whole. We shall select his explanation of the monsoons. The winds in the gulf of Bengal are generally said to blow six months from the N. E. and the other six from the S. W. This is far from being precisely true respecting any part of India; it is, however, sufficiently accurate for our present purpose, and therefore I shall in part adopt this position, as well as the common country name of monsoon; trusting, that in the course of this inquiry I shall be able to account for the several deviations of the wind from the monsoon points, and at the same time in some measure to explain the causes of them. From the island of Ceylon to Balasore Roads, the N. E. monsoon is said to begin near the coast of Coromandel, early in October. But in fact between the two monsoons, the expiration of the one and the commencement of the other, the winds and currents are variable on this coast, partaking of both; frequently, however, calms prevail during the whole month of September, and even early in October, with a strong current from the N. E. towards the S. W. At this period we must remember that the sun is fast approaching towards the equinoxial, which he crosses nearly about the 22d of September. As his declination afterwards increases from seven to fifteen degrees S. which is between the 10th and 31st of October, his ab sence from the northern hemisphere begins to be felt; and as he at the same time rarefies the air both by sea and land to the southward of the equator, the warm air then over the Indian Ocean, but particularly over the eastern side of the continent of Africa, as usual ascends, and the cold air from the N. meeting the perennial east wind, they pass forward progressively, beginning where the rarefaction takes place, and probably continuing to an immense distance, and thus form the N. E. monsoon. The exact point where the northerly wind terminates I shall not, in this place, attempt to ascertain; but we may venture to suppose, that it must be at least as far towards the N. E. as the west side of the Thibet and Napal mountains, separating India from China, and which in winter are always covered with snow. From this frozen eminence a current of cold air will move with considerable velocity towards the tropic, on the approach of the sun, until the equilibrium is restored; but at the latter end of January, the sun again beginning to return towards the N. produces a sensible effect on the air; for in proportion as he approaches towards the equator, the current of air in the gulf of Bengal, near the land, takes a different direction. About this time the wind, immediately on the coast of Coromandel, no longer blows violently or regularly from the N. E. as in the commencement of the monsoon; but first abates in strength (like a current of water when the level is nearly restored), and then changes daily to regular land and sea breezes, which of course, near the coast, are obviously occasioned by the alternate rarefaction of the air by sea and land. When the earth begins to be violently heated in the course of the day, the rarefied air ascends, and the cooler air from the sea comes in to supply its place; but the exhalations raised during the day are condensed in the cool of the evening, during the absence of the sun, and falling down in copious, dews refresh the earth, when the sea becomes warmest, and the current of air, a few hours after sun-set, goes from the land to the sea, and produces what is called the land wind. It must be remembered, that these alternate land and sea breezes do not take place until some time after the change of each monsoon, when its strength begins to abate; for at the com mencement of either, the monsoon itself blows incessantly for a month or five weeks immediately on the coast, and continues, with trifling deviations from the N. E. or S. W. according to the respective seasons. Nor do the land and sea breezes at any time extend above three or four leagues from the shore.' P.41. During the continuance of the land and sea breezes on the coasts of Coromandel and Malabar, both in the N. E. and S. W. monsoons, the wind on shore seems regularly to follow the course of the sun, and passes very perceptibly round every point of the compass in twenty-four hours. • These winds blow constantly every year on the coast of Coromandel to the latter end of January, and continue during February and to the beginning of March, subject to very slight variations; but as the sun approaches towards the vernal equinox, the winds again become variable for some days, as they were about the autumnal equinox, until his declination is upwards of seven degrees N. when the S. W. monsoon sets in, and often on the south part of the coast,' with considerable violence: This change or reflux of air appears to be put in motion by the same means as that which comes from the opposite quarter; for as the sun's altitude increases daily in the northern hemisphere, the extensive body of land in the N. E. part of Asia must become much hotter than the ocean, and consequently a considerable degree of rarefaction will be produced over that part of the continent, whilst at the same season an immense body of cold air will come both from the Indian Ocean and the continent of Africa, in the southern hemisphere, to restore the equilibrium. The princi pal tracts of land of different temperatures on the two continents, bearing very nearly N. E. and S. W. of each other, will therefore become alternately the two opposite extreme points of rarefaction and condensation, and necessarily, according to this theory, be the immediate causes of the N. E. and S. W. monsoons. • But to those who have not considered the nature of the mon soons in India, it may appear somewhat inconsistent with this theory, that the N. E. monsoon, which blows with great force in October and November on the Coromandel coast, is scarcely felt a few degrees to the westward on the Malabar coast, and so vice versa. The S. W. monsoon, which blows with great strength on the Malabar coast in April, May, June, and July, is never felt with any degree of violence on that of Coromandel after its commencement, nor even then, excepting very far to the southward. It is true both coasts are in the northern hemisphere, and might be supposed subject to the same effects from the situation of the sun; and so they certainly are in some degree, for the wind blows nearly in the same direction on both sides of] the peninsula; but on referring to the map, it will be found that the two coasts are separated by a double range of moun tains, running almost N. and S. the one immediately bounding the coast of Malabar, the other nearly in the middle of the peninsula, called the Ballagat, or country above the Passes; both which serve alternately as a screen to either coast during the different monsoons! Besides, they not only break the force of the wind, or current of air, but these mountains, being less electrified than the clouds coming from the sea, attract them, and it is supposed, when nearly in con tact, take away their electrical fire, and cause them to precipitate the water they contain.' P. • 44. Had colonel Capper looked into the modern authors, he would have found that electricity is chiefly conspicuous when water is either dissipated in vapour, or decomposed; and that Dr. Franklin, who, on this subject, then in its infancy, scarcely ventured beyond hints, is undoubtedly in an error. Many facts on the same topic have been adduced in a work, of which, from its obscurity and distance, our author has probably never heard: viz. a volume of essays, published at Exeter within a few years. The rains on the coasts of Malabar and Coromandel are well explained, from the vicinity of the eastern and western seas; and the facts are well established, whatever be the mode of expla nation. We shall go on with his theory of the monsoons. - The island of Ceylon, which lies to the southward of the Coromandel 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 Bala➡ sore 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 direction; 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 direc tion 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 near 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 de grees 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 meridian is a range of mountains, forming the eastern boundary of the Valley of Baramaul, where the high land of Mysore commences, common ly 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 Co romandel, 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 produced 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 ther mometer of Fahrenheit 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 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 be comes more faint, and like the slack water between the flood and ebb tides, the air in the gulf of Bengal has little motion. Fre quently it moves about in eddies, and after it has fluctuated between. the two monsoons for three weeks, sometimes almost a month, being attended with squalls 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.' P. 52. The length of this explanation prevents us from adding some additional remarks, and occasionally apparent exceptions to the doctrine; and indeed the whole of this part of the subject is ingeniously and correctly illustrated. But, with respect to hurricanes, the doctrine will by no means apply. Temporary' strong gusts of wind can never be produced by rarefaction of the air from a vertical sun, because the cause acts gradually, and there |