causes of which I am ignorant. When I press a blown bladder between my knees, and find I cannot bring its sides together, but my knees feel a springy matter, pushing them back to a greater distance, or repelling them, I conclude that the air it contains is the cause. And, when I operate on the air, and find I cannot by pressure force its particles into contact, but they still spring back against the pressure, I conceive there must be some medium between its particles that prevents their closing, though I cannot tell what it is. And, if I were acquainted with that medium, and found its particles to approach and recede from each other, according to the pressure they suffered, I should imagine there must be some finer medium between them, by which these operations were performed.

I allow that increase of the surface of a body may occasion it to descend slower in air, water, or any other fluid; but do not conceive, therefore, that it lessens its weight. Where the increased surface is so disposed as that in its falling, a greater quantity of the fluid it sinks in must be moved out of its way, a greater time is required for such removal. Four square feet of sheet-lead sinking in water broadways, cannot descend near so fast as it would edgeways, yet its weight in the hydrostatic balance, would, I imagine, be the same, whether suspended by the middle or by the corner.

I make no doubt but that ridges of high mountains do often interrupt, stop, reverberate, or turn the winds that blow against them, according to the different degrees of strength of the winds, and angles of incidence. I suppose, too, that the cold upper parts of mountains may condense the warmer air that comes near them, and so, by making it specifically heavier, cause it to descend on one or both sides of the ridge into the

warmer valleys, which will seem a wind blowing from the mountain.

the

Damp winds, though not colder by the thermometer, give a more uneasy sensation of cold, than dry ones; because (to speak like an electrician) they conduct better; that is, are better fitted to convey away the heat from our bodies. The body cannot feel without itself; our sensation of cold is not in the air without the body, but in those parts of the body, which have been deprived of their heat by the air. My desk and its lock are, I suppose, of the same temperament when they have been long exposed to the same air; but now, if I lay my hand on the wood, it does not seem so cold to me as the lock; because (as I imagine) wood is not so good a conductor, to receive and convey away heat from my skin and the adjacent flesh, as metal is. Take a piece of wood, of the size and shape of a dollar, between the thumb and finger of one hand, and a dollar, in like manner, with the other hand; place the edges of both, at the same time, in the flame of a candle; and, though the edge of the wooden piece takes flame, and the metal piece does not, yet you will be obliged to drop the latter before the former, it conducting the heat more suddenly to your fingers. Thus we can, without pain, handle glass and China cups filled with hot liquors, as tea, &c., but not silver ones. A silver tea-pot must have a wooden handle. Perhaps it is for the same reason, that woollen garments keep the body warmer than linen ones equally thick; woollen keeping the natural heat in, or, in other words, not conducting it out to air.

In regard, to water-spouts, having, in a long letter to a gentleman of the same sentiment with you as to their direction, said all that I have to say in support of my opinion, I need not repeat the arguments therein con

tained, as I intend to send you a copy of it by some other opportunity, for your perusal. I imagine you will find all the appearances you saw, accounted for by my hypothesis. I thank you for communicating the account of them. At present I would only say, that the opinion of winds being generated in clouds by fermentation is new to me, and I am unacquainted with the facts on which it is founded. I likewise find it difficult to conceive of winds confined in the body of clouds, which I imagine have little more solidity than the fogs on the earth's surface. The objection from the freshness of rain-water is a strong one; but I think I have answered it in the letter above mentioned, to which I must beg leave at present to refer you.

Extracts from Dampier's Voyages, relating to WaterSpouts.

READ AT THE ROYAL SOCIETY, DECEMBER 16тн, 1756.

"A SPOUT is a small ragged piece or part of a cloud, hanging down about a yard seemingly, from the blackest part thereof. Commonly it hangs down sloping from thence, or sometimes appearing with a small bending, or elbow, in the middle. I never saw any hang perpendicularly down. It is small at the lower end, seeming no bigger than one's arm, but still fuller towards the cloud from whence it proceeds.

"When the surface of the sea begins to work, you shall see the water for about one hundred paces in circumference, foam and move gently round, till the whirling motion increases; and then it flies upwards in a pillar, about one hundred paces in compass at the bottom, but gradually lessening upwards, to the smallness

of the spout itself, through which the rising sea-water seems to be conveyed into the clouds. This visibly appears by the clouds increasing in bulk and blackness. Then you shall presently see the cloud drive along, though before it seemed to be without any motion; the spout also keeping the same course with the cloud, and still sucking up the water as it goes along; and they make a wind as they go. Thus it continues for half an hour, more or less, until the sucking is spent, and then, breaking off, all the water which was below the spout, or pendulous piece of cloud, falls down again into the sea, making a great noise with its falling and clashing motion in the sea.

"It is very dangerous for a ship to be under a spout when it breaks; therefore we always endeavour to shun it, by keeping at a distance, if possibly we can. But, for want of wind to carry us away, we are often in great fear and danger; for it is usually calm when spouts are at work, except only just where they are. Therefore men at sea, when they see a spout coming, and know not how to avoid it, do sometimes fire shot out of their great guns into it, to give it air or vent, that so it may break; but I did never hear that it proved to be of any benefit.

"And, now we are on this subject, I think it not amiss to give you an account of an accident that happened to a ship once on the coast of Guinea, some time in or about the year 1674. One Captain Records, of London, bound for the coast of Guinea, in a ship of three hundred tons and sixteen guns, called The Blessing, when he came into latitude seven or eight degrees north, he saw several spouts, one of which came directly towards the ship, and he, having no wind to get out of the way of the spout, made ready to receive it by furling the sails. It came on very swift, and broke a

little before it reached the ship, making a great noise, and raising the sea round it, as if a great house, or some such thing, had been cast into the sea. The fury of the wind still lasted, and took the ship on the starboard bow with such violence, that it snapt off the bowsprit and fore-mast both at once, and blew the ship all along, ready to overset it; but the ship did presently right again, and the wind whirling round took the ship a second time with the like fury as before, but on the contrary side, and was again like to overset her the other way; the mizzen-mast felt the fury of this second blast, and was snapt short off, as the fore-mast and bowsprit had been before. The mainmast and the main-top-mast received no damage, for the fury of the wind (which was presently over) did not reach them. Three men were in the fore-top when the fore-mast broke, and one on the bowsprit, and fell with them into the sea, but all of them were saved. I had this relation from Mr. John Canby, who was then quartermaster and steward of her; one Abraham Wise was chief mate, and Leonard Jefferies second

mate.

"We are usually much afraid of them, yet this was the only damage that I ever heard done by them. They seem terrible enough, the rather because they come upon you while you lie becalmed, like a log in the sea, and cannot get out of their way. But, though I have seen and been beset by them often, yet the fright was always the greatest of the harm."- - Dampier, Vol. I. p. 451.

Account of a Spout on the Coast of New Guinea.

“WE had fair, clear weather, and a fine moderate gale from southeast to east-by-north; but at daybreak

VOL. VI.

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