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5. General Remarks on Tornados or Whirlwinds. It has long been supposed that these phænomena are immediately connected with atmospheric electricity, and produced by its irre. gular diffusion : and it must be obvious from the preceding articles in this section, that hurricanes, or wind-tempests, are precisely of the same nature as toroados or whirlwinds, only somewhat less de. fined and limited in their action.
The ancients supposed *, that there were great varieties of whirl. winds, of which Pliny and Seneca give different accounts.
The tyhon, Tupwy, is defined by them, vortex igne faetus, a vor. tex produced by fire, which causes dreadful hurricanes of wind, and destroys all things that come within its reach.
The prester comes from trgyow, incendo, inflammo. It was said to break forth with strong flashes of lightning, and to be generally accompanied with an echephias.
The latter is from vemos, nubes, and is described as a sudden and impetuous wind, bursting forth from a dark cloud with little rain.
The exhydria was a violent whirlwind, attended with a great quantity of rain, and in fact the principal difference between an exhydria and an ecnephias was in the quantity of rain or water, which they were supposed to contain.
These whirlwinds are evidently of the same family, all the fea. tures of them being exactly similar, with some slight variations of character.
When a sudden and violent change is produced by fire, either common or electrical, in a considerable body of the atmosphere, the air from all sides suddenly rushes forward, and consequently .concentrating to a point, forms a vortex; and when the cohesion of the air is broken, it will also of course precipitate the water it contains, and produce an ecnephias or exhydria; or where there is but little moisture in the atmosphere, a typhon or prester. The two first are probably the ascending whirlwinds, the others those which descend.
*Air ascending or descending, says Dr. Franklin, may form the same kind of eddies or whirlings, the parts of air requiring a circalar motion, and receding from the middle of the circle by a
• There is a little incorrectness in this explanation of whirlwinds, as the reader will perceive on turning to chapter xli, section is
centrifugal force, and leaving there a vacancy. If descending, it will be greatest above and will lessen downwards. If ascending, it will be greatest below and will lessen upwards, like a speaking trum. pet standing with the largest end on the ground.
When the air descends with violence in some places, it may rise with equal violence in others, and form both kinds of whirlwinds. The air in its whirling motion receding every way from the centre or axis of the trumpet, leaves there a vacuum, which cannot be filled through the sides, the whirling air as an arch preventing; it must then press in at the open ends. The greatest pressure in. wards must be at the lower end, the greatest weight of the sur. rounding atmosphere being there; the air entering rises within, and carries up dust, leaves, and heavier bodies, that happen to be in its way, as the eddy or whirl passes over land.
If it passes over water, the weight of the surrounding atmo. sphere forces up the water into the yacuity, part of which by de. grees joins with the whirling air, and adding weight, and receiving accelerated motion, recedes still further from the centre or axis of the trump as the pressure lessens, and at last, as the trump widens, is broken into small particles, and so united with air as to be sup. ported by it, and become black clouds at the top of the trump.
Thus these eddies may be whirlwinds at land and water-spouts at sea. A body of water so raised may be suddenly let fall, when the motion, &c. has not strength to support it, or the whirling arch is broken so as to admit the air falling into the sea. It is harmless, unless ships unfortunately happen to be directly under it; but if in the progressive motion of the whirl it has moved from the sea over the land, and there suddenly breaks, violent and mischievous tor, rents are the consequence.
6. Dreadful Whirlwind at Cambridge in New England.
By Professor Winthrop. The morning of July 10, 1761, at Cambridge, was fair and hot with a brisk gale at south-west. The afternoon was cloudy. About five it began to rain, and thundered once. At Leicester, forty miles westward, about five o'clock the sky looked strangely; clouds from the south west and north-west seemed to rush to. gether very swiftly, and immediately on their meeting commenced a circular motion; presently after which a terrible noise was heard. The whirlwind passed along from south-west to north-west. Its first effects were discernible on a bill, where several trees were thrown down at considerable distances from each other. In this manner it proceeded the distance of six miles with the most destruc. tive violence, tearing up and scattering about the trees, stones, fences, and every thing else in its way, forming a continued lane of ruins, of a few rods wide.
It met with only one dwelling-house in its course, that of one David Lynde, on which it fell with the utmost fury, and in a moment effected its complete destruction.
The house was of wood, two stories high, and both the chim. neys of stone. Near the house were a shop and small shed ; and the barn stood on the opposite side of the road, about ten rods dis. tant. As soon as they perceived the storm coming near the house some men within endeavoured to shut the south door ; but before they could effect it they were surprized by the falling of stones around them, from the top of the chimney which was in the mid. dle of the house. All the people in the house were in that in. stant thrown into such a consternation, that they can give no ac. count of what passed during this scene of confusion, which was indeed very short. Where the house stood nothing remained but the sills, and greater part of the lower floor, with part of the two stacks of chimneys, one about ten feet, and the other not quite so high; the stones which had composed the upper part lying all around them. Except these sills, there were only three pieces of timber, and those very large, left entire; one of which, about sixteen feet long, and ten inches by eight, was found on the opposite side of the road, nearly south, about twenty rods distant from the house. The rest of the timbers, from the greatest to the least, lay broken and twisted to pieces between N.N.E. and E. for seventy or eighty rods from the house ; some on the ground, others sticking into it a foot and two feet deep in all directions. Part of one of the main posts, about ten feet long, with part of one of the plats of nearly the same length, and a brace which holds them together, were left sticking in the ground, nearly perpendicular, to a great depth, in a field southerly from the house, about eight rods distant. The boards and shingles of the house, three or four
thousand new boards which lay by it, were so entirely shattered, that scarcely a piece could be found above four or five inches wide, and vast numbers were not more than two fingers wide ; some within the course of the wind and some without, at great distances on both sides of it. What has been said of the boards and shingles was likewise true of the wooden furniture of the house: the tables, chairs, desks, &c. shared the same fate ; not a whole stick was to be found of any of them. Some of the beds that were found were hanging on high trees at a distance. Of the heavy utensils, pewter, kettles, and iron pots, scarcely any was found. Some nails that were in a cask in the east chamber were driven in great numbers into the trees on the eastern side of the house. The shop and shed before mentioned were toro in pieces, nothing of the shop remained but the sills and floor; and a horse standing under the shed was killed. Only one person was killed.
From the whole, it seems highly probable that the house was suddenly plucked off from the sills (to which the upright posts are not fastened), and taken up into the air, not only above the heads of the persons who were on the lower floor, but to the height of those parts of the chimneys which were left standing, where, by the vio. lent circular motion of the air, it was immediately hurled into ten thousand pieces, and scattered to great distances on all quarters, except that from which the wind proceeded. And it further appears, that the violence of the wind in that place was over as soon as the house was taken up; otherwise no person could have been left on the floor.
[Phil. Trans, 1761,
7. Whirlwind at Corne• Abbas in Dorsetshire,
By Mr. J. Dorby.
On Saturday October 30, 1731, about a quarter before one in the night, there happened at Corne-Abbas, at Dorsetshire, a very sudden and terrible wind whirl-puff, as Mr. D. calls it: some say it was a water-spout, and others a vapour or exhalation from the earth. It began on the south west side of the town, passing directly to the north-east, crossing the middle of the town in breadth 200 yards. It stripped and uncovered tiled and thatched houses, rooted trees out of the ground, broke others in the midst, of at least a foot square, and carried the tops a considerable way. The sigo of the new inn, a sign of five feet by four, was broken off six feet in the pole, and carried cross a street of forty feet breadth," and over an opposite house. It took off and threw down the pinacles and battlements of one side of the tower; by the fall of which, the leads and timber of great part of the north aisle of the church were broken in. The houses of all the town were so shocked, as to raise the inhabitants. No hurt was done but only across the middle of the town in a line. Nor no life lost. No other part of the neighbourhood or country so much as felt or heard it. It is supposed by the most judicious, that it began and ended within the space of two minutes. It was so remarkably calm a quarter after twelve, that the exciseman walked through two streets, and turned a corner, with a naked lighted candle in his hand, unmolested and undisturbed by the air; and as soon as over, a perfect calm, but was soon followed by a surprising violent rain.
[Phil. Trans. 1739.
8. Relation of two considerable Hurricanes in
By Mr. John Templer.
OCTOBER 30, 1669, between five and six o'clock in the after. noon, the wind being westerly, at Ashly, in Northamptonshire, there happened a formidable hurricane, scarce bearing sixty yards in its breadth, and spending itself in about seven minutes of time. Its first observed assault was on a milk-maid, taking her pail and hat from off her head, and carrying her pail many scores of yards from her, where it lay undiscovered some days. Next it stormed the yard of one Sprigg, in Westthorp, a name of one part of the town, where it blew a waggon body off the axle-trees, breaking the wheels and axle trees in pieces, and blowing three of the wheels so shattered over a wall: this waggon stood somewhat cross to the passage of the wind. Another waggon of Mr. Salisbury's was driven with great speed on its wheels against the side of his
* Perhaps these ought rather to be called tornados or whirlwinds, than hurricanes, we have retained, however, the term employed in the original, and have chietly copied them to shew how nearly the whirlwind and hurricane are united. -EDITOR.