me to let you know what I am at a loss about in your papers, which is only in the article of the water-spoutI am in doubt, whether water in bulk, or even broken into drops, ever ascends into the region of the clouds per vorticem; i. e. whether there be, in reality, what I call a direct water-spout. I make no doubt of direct and inverted whirl-winds; your description of them, and the reason of the thing, are sufficient. I am sensible too, that they are very strong, and often move considerable weights. But I have not met with any historical accounts that seem exact enough to remove my scruples concerning the ascent abovesaid,

Descending spouts (as I take them to be) are many times seen, as I take it, in the calms, between the sea and land trade-winds on the coast of Africa. These contrary winds, or diverging, I can conceive may occasion them, as it were by suction, making a breach in a large cloud. But I imagine they have, at the same time, a tendency to hinder any direct or rising spout, by carrying off the lower part of the atmosphere as fast as it begins to rarefy; and yet spouts are frequent here, which strengthens my opinion, that all of them descend.

But however this be, I cannot conceive a force producible by the rarefication and condensation of our atmosphere, in the circumstances of our globe, capable of carrying water, in large portions, into the region of the clouds. Supposing it to be raised, it would be too heavy to continue the ascent beyond a considerable height, unless parted into small drops; and even then, by its centrifugal force, from the manner of conveyance, it would be flung out of the circle, and fall scattered, like rain.

But I need not expatiate on these matters to you.

I

I

have mentioned my objections, and, as truth is my pursuit, shall be glad to be informed. I have seen few accounts of these whirl or eddy winds, and as little of the spouts; and these, especially, lame and poor things to obtain any certainty by. If you know any thing determinate that has been observed, I shall hope to hear from you; as also of any mistake in my thoughts. I have nothing to object to any other part of your suppositions: and as to that of the trade-winds, I believe nobody can.

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I am, &c.

P. S. The figures in the Philosophical Transactions show, by several circumstances, that they all descended, though the relators seemed to think they took up water.

DR. PERKINS OF BOSTON, TO BENJAMIN FRANK LIN, ESQ. AT PHILADELPHIA.

SIR,

The same Subject continued.

Read at the Royal Society, June 24, 1756.

Boston, October 23, 1752.

IN the inclosed, you have all I have to say of that matter. It proved longer than I expected, so that I was forced to add a cover to it. I confess it looks like a dispute; but that is quite contrary to my intentions.

• Water-Spouts.

The

The sincerity of friendship and esteem were my motives; nor do I doubt your scrupling the goodness of the intention. However, I must confess I cannot tell exactly how far I was acted by hopes of better information, in discovering the whole foundation of my opinion, which, indeed, is but an opinion, as I am very much at a loss about the validity of the reasons. I have not been able to differ from you in sentiment concerning any thing else in your Suppositions. In the present case I lie open to conviction, and shall be the gainer when informed. If I am right, you will know that, without my adding any more. Too much said on a merely speculative matter, is but a robbery committed on practical knowledge. Perhaps I am too much pleased with these dry notions: however, by this you will see that I think it unreasonable to give you more trouble about them, than your leisure and inclination may prompt you to.

I am, &c.

SINCE my last I considered, that, as I had begun with the reasons of my dissatisfaction about the ascent of water in spouts, you would not be unwilling to hear the whole I have to say, and then you will know what I rely upon.

What occasioned my thinking all spouts descend, is, that I found some did certainly do so. A difficulty apIpeared concerning the ascent of so heavy a body as water, by any force I was apprised of, as probably sufficient. And, above all, a view of Mr. Stuart's portraits of spouts, in the Philosophical Transactions.

Some observations on these last will include the chief part of my difficulties.

Mr.

Mr. Stuart has given us the figures of a number observed by him in the Mediterranean: all with some particulars which make for my opinion, if well drawn.

The great spattering, which relators mention in the water where the spout descends, and which appears in all his draughts, I conceive to be occasioned by drops descending very thick and large into the place.

On the place of this spattering, arises the appearance of a bush, into the centre of which the spout comes 'down. This bush I take to be formed by a spray, made by the force of these drops, which being uncommonly large, and decending with unusual force by a stream of wind descending from the cloud with them, increases the height of the spray: which wind being repulsed by the surface of the waters rebounds and spreads; by -the first raising the spray higher than it otherwise "would go; and by the last making the top of the bush appear to bend outwards (i. e.) the cloud of spray is -forced off from the trunk of the spout, and falls backVward.

The bush does the same where there is no appearance of a spout reaching it; and is depressed in the middle, where the spout is expected. This, I imagine, to be from numerous drops of the spout falling into it, together with the wind I mentioned, by their descent, 'which beat back the rising spray in the centre.

This circumstance, of the bush bending outwards at the top, seems not to agree with whatol call a direct whirlwind, but consistent with the reversed; for a direct one would sweep the bush inwards; if, in that case, any thing of a bush would appear.

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The pillar of water, as they call it, from its likeness, suppose to be only the end of the spout immersed in

the bush, a little blackened by the additional cloud, and, perhaps, appears to the eye beyond its real bigness, by a refraction in the bush, and which refraction may be the cause of the appearance of separation, betwixt the part in the bush, and that above it. The part in the bush is cylindrical, as it is above (i. e.) the bigness the same from the top of the bush to the water. Instead of this shape, in case of a whirlwind, it must have been pyramidical.

Another thing remarkable, is, the curve in some of them: this is easy to conceive, in case of descending parcels of drops through various winds, at least till the cloud condenses so fast as to come down, as it were, uno rivo. But it is harder to me to conceive it in the ascent of water, that it should be conveyed along, secure of not leaking or often dropping through the under side, in the prone part: and, should the water be ¿conveyed so swiftly, and with such force, up into the cloud, as to prevent this, it would, by a natural, disposition to move on in a present direction, presently ⚫ straiten the curve, raising the shoulder very swiftly, till lost in the cloud.

Over every one of Stuart's figures, I see a cloud: I suppose his clouds were first, and then the spout; I do not know whether it be so with all spouts, but suppose it is. Now, if whirlwinds carried up the water, I should expect them in fair weather, but not under a cloud; as is observable of whirlwinds; they come in fair weather, not under the shade of a cloud, nor in the night; since shade cools the air: but, on the contrary, violent winds often descend from the clouds; strong gusts which occupy small spaces; and from the higher regions, extensive hurricanes, &c.

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