From John Perkins
ALS: American Philosophical Society9
Boston Octobr. 16. 1752
I received yours of Septr. with the Observations for which I am obliged to you.1 It is a very informing Piece and I think it should be read and well considerd by every Englishman who wishes well to his Country But more especially by those in power and Ability to promote the Nation’s Intrest.
Your Papers on the Weather2 I deliver’d to your Brother Franklin in the Summer past and the other this Day. I am sorry for his bad State of Health and heartily wish his Usefulness might be long continued.
I find by a word or two in your last that you are willing to be found Fault with which authorises me to let you know what I am at a loss about in your Papers which is only in the Article of the Water-Spout. I 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 Whirlwinds. 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 hystorical 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 imagin they have at the same time a Tendencie to hinder any Direct or rising Spout by carrying off the lower part of the Atmosphere as fast as it begins to rarifie: 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 Rarifaction and condensations of our Atmosphear 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 scatter’d like Rain.
But I need not expatiate on these Matters to you. I have mention’d my Objections and as Truth is my persuite shall be glad to be inform’d. 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 Tho’ts.
I have nothing to object to any other part of your Suppositions and as to that of the Trade-Winds I believe nobody can.
The air of assurance, the Language and Manner of Performance, you know how to excuse for one who is with as much Sincerity as the politest Your very much Obliged Humble Servant
Postscript. The Figures in the Philos. Trans.3 show by several circumstances that they all descended. Tho’ the Relators seem’d to think they took up water.
9. Printed in Exper. and Obser., 1769 edit., pp. 207–9, but without the first two and the last paragraphs of the letter. It was read in the Royal Society, June 3, 1756.
1. Not found. The Observations were BF’s on the Increase of Mankind (see above, p. 225).
2. Probably the Physical and Meteorological Observations, Conjectures and Suppositions (above, pp. 235–43), and some other paper not found.
3. Alexander Stuart, “Part of a Letter … concerning some Spouts he observed in the Mediterranean,” Phil. Trans., XXIII (1702–03), 1077–80, with plate of illustrations.