viewing a water-spout so near them, as I did this, without receiving some injury from it; and indeed the master and sailors were more anxious from the danger of its approach, in preparing against the danger, than in observing it accurately as I did.

I saw several others in the same voyage, at a greater distance, and, from all of them, I am as fully convinced as I can be of any thing from my senses, that the common opinion of sucking up the sea-water is false. If the water had been sucked up, there must have been a rising in the sea directly under the point of the spout; whereas there was a hollow in the sea, which I distinctly saw, and the spray rising round the hollow as happens by the force of wind from the pipe of a pair of bellows. The avoiding of the danger by firing a shot through the pipe, which you mention as an objection, confirms rather than weakens what I say, by giving a horizontal vent to the wind, by which it goes over the ship, and does not strike.

If you consider the particulars in the description of the spouts, which I saw, as I wrote them to Mr. Franklin in that and in a subsequent letter, you will be convinced that the spout was not formed by sucking water. I would not have it thought that, in my opinion, never any great quantity of rain or water falls from those clouds. On the contrary, I think, that, after the fermentation in the clouds, which supports them in the air and generates the wind, is lessened or ceases, then they may fall in prodigious pouring showers, but not confined to the diameter of two or three yards, as the wind from the spout is. The rain, I believe, never or seldom falls at the time the spout is seen, but afterwards and at distances from that place. If the clouds sucked up the sea-water, when it fell again it must at least be brackish. I cannot conceive how the

sucking up of sea-water can divest it of its saline qualities; or if the water were divested of its salt in the clouds, the salt must fall down again somewhere to the sea or land. Salt water, I think, was never observed to come from the clouds.

Mr. Franklin tells me, that another gentleman was of the same opinion with me, of wind issuing from the water-spout, though neither of us knew the other's opinion, and I am still ignorant of the facts on which he formed his.

As you have my former papers on whirlwinds, &c., I now send you an account of one which I had lately an opportunity of seeing and examining myself.

Being in Maryland, riding with Colonel Tasker, and some other gentlemen, to his country-seat, where I and my son were entertained by that amiable and worthy man with great hospitality and kindness, we saw, in the vale below us, a small whirlwind beginning in the road, and showing itself by the dust it raised and contained. It appeared in the form of a sugarloaf, spinning on its point, moving up the hill towards us, and enlarging as it came forward. When it passed by us, its smaller part near the ground appeared no bigger than a common barrel; but, widening upwards,

it seemed, at forty or fifty feet high, to be twenty or thirty feet in diameter. The rest of the company stood looking after it; but, my curiosity being stronger, I followed it, riding close by its side, and observed its licking up, in its progress all the dust that was under its smaller part. As it is a common opinion that a shot, fired through a water-spout, will break it, I tried to break this little whirlwind, by striking my whip frequently through it, but without any effect. Soon after, it quitted the road and took into the woods, growing every moment larger and stronger, raising, instead of dust, the old dry leaves with which the ground was thick covered, and making a great noise with them and the branches of the trees, bending some tall trees round in a circle swiftly and very surprisingly, though the progressive motion of the whirl was not so swift but that a man on foot might have kept pace with it; but the circular motion was amazingly rapid. By the leaves it was now filled with, I could plainly perceive, that the current of air theywere driven by, moved upwards in a spiral line; and when I saw the passing whirl continue entire, after leaving the trunks and bodies of large trees which it had enveloped, I no longer wondered that my whip had no effect on it in its smaller state. I accompanied it about three quarters of a mile, till some limbs of dead trees, broken off by the whirl, flying about and falling near me, made me more apprehensive of danger; and then I stopped, looking at the top of it as it went on, which was visible, by means of the leaves contained in it, for a very great height above the trees. Many of the leaves, as they got loose from the upper and widest part, were scattered in the wind; but so great was their height in the air, that they appeared no bigger than flies. My son, who was by this time come up with me, followed the whirlwind till it left the woods,

and crossed an old tobacco-field, where, finding neither dust nor leaves to take up, it gradually became invisible below, as it went away over that field. The course of the general wind then blowing was along with us as we travelled, and the progressive motion of the whirlwind was in a direction nearly opposite, though it did not keep a straight line, nor was its progressive motion uniform, it making little sallies on either hand as it went, proceeding sometimes faster and sometimes slower, and seeming sometimes for a few seconds almost stationary, then starting forward pretty fast again. When we rejoined the company, they were admiring the vast height of the leaves now brought by the common wind over our heads. These leaves accompanied us as we travelled, some falling now and then round about us, and some not reaching the ground till we had gone near three miles from the place where we first saw the whirlwind begin. Upon my asking Colonel Tasker if such whirlwinds were common in Maryland, he answered pleasantly, "No, not at all common; but we got this on purpose to treat Mr. Franklin." And a very high treat it was to,

Dear Sir,

Your affectionate friend and humble servant,
B. FRANKLIN.

TO JOHN LINING, AT CHARLESTON, SOUTH CAROLINA.

SIR,

On Cold produced by Evaporation.

New York, 14 April, 1757.

It is a long time since I had the pleasure of a line from you; and, indeed, the troubles of our country,

with the hurry of business I have been engaged in on that account, have made me so bad a correspondent, that I ought not to expect punctuality in others.

But, being about to embark for England, I could not quit the continent without paying my respects to you, and, at the same time, taking leave to introduce to your acquaintance a gentleman of learning and merit, Colonel Henry Bouquet, who does me the favor to present you this letter, and with whom I am sure you will be much pleased.

Professor Simson, of Glasgow, lately communicated to me some curious experiments of a physician of his acquaintance, by which it appeared, that an extraordinary degree of cold, even to freezing, might be produced by evaporation. I have not had leisure to repeat and examine more than the first and easiest of them, viz. Wet the ball of a thermometer by a feather dipped in spirit of wine, which has been kept in the same room, and has, of course, the same degree of heat or cold. The mercury sinks presently three or four degrees, and the quicker, if, during the evaporation, you blow on the ball with bellows; a second wetting and blowing, when the mercury is down, carries it yet lower. I think I did not get it lower than five or six degrees from where it naturally stood, which was, at that time, sixty. But it is said, that a vessel of water being placed in another somewhat larger, containing spirit, in such a manner that the vessel of water is surrounded with the spirit, and both placed under the receiver of an air-pump; on exhausting the air, the spirit, evaporating, leaves such a degree of cold as to freeze the water, though the thermometer, in the open air, stands many degrees above the freezing point.

I know not how this phenomenon is to be accounted for; but it gives me occasion to mention some loose