It surprises me a little, that wind, generated by fermentation, is new to you, since it may be every day observed in fermenting liquor. You know with what force fermenting liquors will burst the vessels which contain them, if the generated wind have not vent; and with what force it issues on giving it a small vent, or by drawing the cork of a bottle. Dr. Boerhaave says, that the steam issuing from fermenting liquors received through a very small vent-hole, into the nose, will kill as suddenly and certainly as lightning. That air is generated by fermentation, I think you will find fully proved in Dr. Hale's Analysis of the Air, in his "Vegetable Statics." If you have not read the book, you have a new pleasure to come.

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The solution you give to the objection I made from the contrary winds blowing from the opposite sides of the mountains, from their being eddies, does not please me, because the extent of these winds is by far too large to be occasioned by any eddy. It is forty miles from New York to our mountains, through which Hudson's River passes. The river runs twelve miles in the mountains, and from the north side of the mountains it is about ninety miles to Albany. I have myself been on board a vessel more than once, when we have had a strong northerly wind against us, all the way from New York, for two or three days. We have met vessels from Albany, who assured us that, on the other side of the mountains, they had, at the same time, a strong, continued southerly wind against them; and this frequently happens.

I have frequently seen, both on the river, in places where there could be no eddy-winds, and on the open sea, two vessels sailing with contrary winds, within half a mile of each other; but this happens only in easy winds, and generally calm in other places near these winds.

You have, no doubt, frequently observed a single cloud pass, from which a violent gust of wind issues, but of no great extent. I have observed such a gust make a lane through the woods, of some miles in length, by laying the trees flat to the ground, and not above eight or ten chains in breadth. Though the violence of the wind be in the same direction in which the cloud moves and precedes it, yet wind issues from all sides of it; so that, supposing the cloud moves southeasterly, those on the northeast side of it feel a southwest wind, and others on the southwest side, a northeast. And where the cloud passes over, we frequently have a southeast wind from the hinder part of it, but none violent, except the wind in the direction in which the cloud moves. To show what it is which prevents the wind from issuing out equally on all sides, is not an easy problem to me, and I shall not attempt to solve it; but when you shall show what it is which restrains the electrical fluid from spreading itself into the air surrounding it, when it rushes with great violence through the air along, or in the conductor, for a great extent in length, then I may hope to explain the other problem, and remove the difficulty we have in conceiving it.

FROM CADWALLADER COLDEN TO B. FRANKLIN.

New Theory of the Motion of the Planets best suited for calculating Astronomical Tables. - Abbé Nollet's Book.

DEAR SIR,

Coldenham, 2 April, 1754.

I should have acknowledged your favor of the 1st of January sooner, if you had not at the same time told

me, that you were to be from home for some time after the writing of it; and I had my mind engaged in a chain of thinking that I was unwilling to interrupt, as that season was the only time of the year in which I could hope to pursue it without interruption. My design was to show, by the best observations made in the space of two hundred and seventy years, that the theory of the motion of the planets, which I have formed, agrees better with the appearances in the heavens than any theory hitherto published; and that tables may be formed on that theory more correct than any that have hitherto appeared, without excepting those formed by Dr. Halley and published so lately as 1749, which I can show, from Mr. Flamsteed's and Lord Maclesfield's observations, to be almost everywhere faulty. This I am the more fond of, because it is not so much for the pleasure of imagination and amusement, as of real use, but attended with exceeding great care, attention, and trouble.

You have given me an anxious longing to your answer to the Abbé Nollet's objections to your theory, as I make no doubt of its being made more evident thereby, and cleared from any obscurities, which such things are unavoidably subject to, at first appearing, especially with those that are not much conversant with the subject. Persons who write in the manner the Abbé does, not for the sake of truth and information, but to secure or gain a reputation, seldom avoid losing what they chiefly intend to preserve. The justice, which I hear is done to your merit by the Royal Society, makes full recompense for these little abuses, and I heartily congratulate you upon it.

If you think proper to communicate your answer to the Aboé Nollet to me, before you transmit it, you may assure yourself of my making remarks with that free

dom which should always subsist between friends, and with less care of exposing my own want of knowledge, than of observing on every thing that I shall think may want correction.

Your favor of the 10th of March surprised me, by finding that you had a copy of a letter, which I wrote last fall, or beginning of winter, to Mr. Franklin on water-spouts; because I did not write it with any thoughts, that it would have gone farther than for his private perusal; but, since you take notice of it as a novelty, which destroys the commonly received opinion, you lay me under some necessity of adding something more to it. For, as to the facts therein related, they are certainly true as far as I can trust my eyes and ears. I did, at the time, commit the account of what I saw to writing; but it is so long since, that these, with several other observations made about that time, are lost, or perhaps some one of my friends got the perusal of them, and has not restored them. But the appearance made so strong an impression on me, that I dare trust to my memory, even at this distance of time; and perhaps few, who were curious enough to observe this phenomenon, without being prejudiced by received opinions, if any have had an opportunity of

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