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of, was the 25th of July, and the latest the 8th of September; but the usual morth is August.
The method of avoiding the danger is to keep the ship sailable, with good store of ballast, the ports well barred and caulked, the top-masts and tops down, the yards laced a-port, keeping the doors and windows of the ship fast, and she will lie as well as in other storms; thus the ship being in readiness, they may stay in the road till the storm begins, which is always first at north, so to the north-west, till it comes round to the south-east, and then its fury is over. So with the north wind they may run away to the south, to get themselves sea-room, for the drift of the south-west wind, where it blows very fiercely. By these means, I have, by God's blessing, preserved myself in two hurricanes at sea, and in three at shore, greatly to my advantage, as I lost not a sail, yard, or mast in two great hurricanes.
The causes of these hurricanes, according to experimental ob. servations of my time, are these :
1. It is known to men of experience, that to the southward of the tropics there is constantly a trade-wind, or easterly wind, which goes from the north to the south-east all the year round; except where there are reversions of breezes, and inlets near the land ; so that when this hurricane, or rather whirlwind, comes in opposi. tion to the constant trade-wind, then it pours down with such violence as exceeds any storms of wind. In the hurricane at Nevis, I saw the high mountain that was covered with trees left in most places bare.
2. It is remarked by all men, that have been in those parts where the sun comes to the zenith, that at his approach towards it, there is always fair weather; but at his return southwards, it oc. casions, off the north parts of the equinoctial, generally much rain and storms, as tornadoes, and the like; which makes the wind in the tornado come on several points. But before it comes, it calms the constant easterly winds; and when they are past, the easterly wind gathers force again, and then the weather clears up fair.
3. The wind being generally between the tropics and the equator easterly, unless at such times as before mentioned : meeting with the opposition of these hurricanes, which come in a contrary
course to that trade-wind, causes this violent whirl.wind, on the sun's leaving the zenith of Barbadoes, and these adjacent islands; by which the easterly wind loses much of its strength; and then the west wind, which is kept back by the power of the sun, with the greater violence and force pours down on those parts where it gets vent. And it is usual in sailing from Barbadoes, or those islands to the north, for a westerly wind, when we begin to lose our easterly wind, to have it calm, as it is before hurricanes : and then the wind springing up, till it comes to be well settled, causes the weather to be various; but after the settled westerly wind comes fresh, they have been constantly without those shuf. flings from point to point.
Here it is to be observed, that all hurricanes begin from the north to the westward, and on those points that the easterly wind blows most violently, the hurricane blows most fierce against it; for from the N.N. E. to the E. S. E. the easterly blows freshest; so does the W.N. W. to the S. S. W. in the hurricane blow most violent; and when he comes back to the SE, which is the com. mon course of the trade.wind, then it ceases of its violence, and so breaks up. Thus I take the cause of hurricanes to be the sun's leaving the zenith of those parts towards the south: and secondly, the reverse or rebounding back of the wind, which is occa. sioned by the calming of the trade-wind.
But it will be objected, why should not this storm be all over those parts of the West Indies, as well as Barbadoes and the Leeward-islands ? To which I answer, that it has in about 25 years of my experience, taken its course from the Bermudas to the Caribees; but seldom or never carries such a breadth as from the latitude of 16 to 32 degrees, which are the latitudes of the places; but it has been observed, that when hurricanes have been in Martinico, which is within two degrees of latitude, and two degrees longitude, according to the miles of that circle, yet no hurricane has been in Barbadoes; nor could I ever call any of the former storms at Barbadoes hurricanes, till that last year in 167,5. Again it has heen noted, that hurricanes have done the like to the northwards : for when the hurricane has been in Antigua and St. Christopher's, those ships that were only in the latitude of twenty degrees, had no hurricane, but constant westerly winds, reason. ably fair, and then there were no hurricanes in Bermudas; and when the hurricanes were at Bermudas, the Leeward or Caribee Islands had no hurricane; nor had those islands the hurricane when Barbadoes had it.
It may be also objected, why the harricane was never known to go farther to the westward than Porto Rico, which lies in or near the latitude of those islands of St. Christopher ? To this I answer, that from Porto Rico, downwards, both that island and Hispaniola, as well as other adjacent islands, are of vast magnitude, and very high lands, that of themselves most commonly give reversal or westerly winds at night, through the year; for there, for the reasons aforesaid, the easterly wind, towards night, calms, and those lands afford a land- wind, which the other islands cannot do, by reason of the smallness of those Caribee Islands; but very near the shore, the trade-wind having its full power till this general whirlwind comes, for the reasons aforesaid. I do imagine likewise, to the southwards of Barbadoes, where the tornadoes come fre. quently, there are no hurricanes; nor was there at Barbadoes, when these tornadoes commonly came there, which made some small reversal, though it was but for two or three hours: yet the easterly wind, giving some way by the sun's declining from that zenith, prevents this furious reverse, where it has no vent till it is forced by the violence of the two winds.
[Phil. Trans. 1698.
2. Hurricanes of the Indian Coast. Dr. Halley seems to consider the hurricanes which blow occa. sionally in the month of October in the Gulf of Bengal, as of a similar nature to those in the West Indies, in which probably he is right; but at the same time it is evident, that he has been mis. informed, respecting the time they generally happen in the East. He observes that our seamen suppose them to be the breaking up of the monsoon. In this circumstance the mariners have misled the pbilosopher; for the hurricanes seldom happen near the change or breaking up of the monsoons, but generally many days after their commencement, and sometimes about the middle of them. Both the N.E. aod S.W. monsoons blow at first in fresh gales, but neither of them encrease to violent hurricanes. It is from very obvious causes already sufficiently explained, that the one dies gradually away before the other begins. But we will first adduce unquestionable proofs of these facts, and then endeavour to ascertain the causes of them.
The first hurricane on the coast of Coromandel, mentioned by Mr. Orme, in his History of Hindustan, was that which destroyed Le Bourdonai's feet, after he had taken Madras in the year 1746. He attacked this fort in September, which surrendered to him in less than a month, on condition that private property should be protected. But Dupluix, the governor of Pondicherry, disputed the right of the admiral to make such a capitulation, and insisted on his seizing all property, both public and private. The corres. pondence on this subject, in which the virtuous admiral strenu. ously defended the rights of individuals and his own honour, de. tained him at Madras with his squadron much longer than otherwise he intended to have stayed; and on the 2d of October came on a hurricane, which in a few hours destroyed almost the whole French fleet, and in which twenty other ships of different nations were driven on shore. One of the ships, says Mr. Orme, foundered in an instant, and only six of the crew were saved. But it must be remembered that four vessels laden with effects sent from Madras, with three others lately arrived at Pondicherry from Europe, were not affected by this hurricane ; the violence of which, therefore, did not extend more than sixty or eighty miles to the southward.
On the 31st ef October, 1753, Mr. Orme mentions also a vio. lept hurricane on land, which was felt mostly near Wandiwash; but as the same author, who is in general equally minute and cor. rect, takes no notice of any bad consequences happening from it at sea, we may reasonably suppose that it did no mischief either at Madras or Pondicherry, although its principal violence was felt nearly half-way between both, and not more than sixty miles in a direct line from either.
The next, which occurred during the N.E. monsoon, was on the 30th of December, 1760, during the siege of Pondicherry. On the evening of that day the weather was fair, the rains had ceased, and there were regular land and sea breezes ; but a heavy swell rolled in on the shore from the S.E. The next morning the sky was of a dusky bue, accompanied with a closeness in the air, but without that wild irregularity which prognosticates a hurricane. Towards the evening, however, the wind freshened from the N.W. and at eight at night encreased considerably. About midnight the wind veered round to the N.E, fell calm with a thick haze, and in a few minutes after flew round to the S.E. whence it blew with great violence. Almost all the ships might have been saved, had they taken the advantage of the wind blowing off the land, but the roaring of the wind and sea prevented the captains from hearing the signals for standing out to sea, and many of the ships were wrecked. The Newcastle, Queenborough, and Protector, were driven on shore a few miles S. of Pondicherry, and the crews were saved. The Norfolk, Admiral Stevens, returned next day; and on the 7th came in the Salisbury from Trinco Trincomalay S. and the Tiger from Madras N.; so that in these opposite directions of E.N. and S. the violence of the storm had not been felt. It is observed by mariners in the East Indies, that these hurricanes usually happen once in five years; but for this opinion I can find no reason, either from what I have heard from others or have myself observed.
The next in succession to that of 1760-61, was in 1763. On the 20th of October in that year, many days after the N.E. monsoon had apparently commenced, the wind began to slacken, and the clouds in the evening appeared uncommonly red, particu. larly on the day preceding the hurricane. On the morning of the 21st a strong wind blew off the land, and in the course of a few hours flew all round the compass. At this time the Norfolk man of war, Admiral Cornish, with the America and Weymouth, and the Royal Charlotte country ship of four hundred tons, remained in Madras roads, with several other country vessels. The wind began to blow from the N.W. and continued from that quarter from three or four hours, of which time the men of war availed themselves to put to sea, but it then suddenly changed to the eastward, and prevented most of the country ships from following their example. After having blown with incessant violence for fourteen urs, and with almost equal strength from every point of the compass, it at length ceased, but literally left only wrecks behind. All the vessels at an anchor were lost, and almost every person on board perished; but the men of war and the Royal Charlotte returned into the roads on the 24th. The former had felt the gale very severely whilst near the coast, but without sustaining any material injury; the latter vessel likewise, from staying rather too long at anchor, had lost her fore and main.masts, and was otherwise much da. maged.