Benjamin Franklin Papers
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From Benjamin Franklin to Benjamin Rush, 22 July 1774

To Benjamin Rush

ALS: Yale University Library; letterbook draft: American Philosophical Society

London, July 22. 1774

Dear Sir,

I received your Favour of May 14. with the very ingenious Oration you deliver’d at the Society, for which I thank you. The Bookseller you had likewise sent it to (Mr. Dilly) being desirous of Dr. Huck’s Opinion and mine as to its Publication, we had, after separately reading it, a little Consultation upon it; the Result of which was, that tho’ the Piece had in many Respects a great deal of Merit, yet as there were some Particulars that would be excepted to by the medical People here, many of whom are in the Royal Society and have great Weight there; and as the Society generally is of late grown more difficult in the Admission of new Members, several Candidates being this last Year rejected; and any Criticism to the Disadvantage of your Piece in the Reviews or otherways might prejudice some Votes against you; we thought it best the Publication should be postpon’d till after the Ballot for your Election; it being intended by us to put you up as a Candidate at the next Meeting of the Society, which will be in November, and we were unwilling to hazard your being refus’d, as it would be better not to propose you than to do it without a moral Certainty of Success. We therefore advis’d the Bookseller not to print it till Winter, which he the more readily agreed to, as that is the best Season for publishing.1 You compliment me too highly in supposing a Preface of mine would be of any Advantage to it.

Your Brother Chymists are now every where in Europe, busy in working upon Fix’d Air: And Dr. Priestly’s Book has put many of our Gentry upon making, by the help of such Air, their own Pyrmont Water. Dr. Nooth has invented a nice Apparatus for this purpose, of which a great Number have been sold. It consists of three Glass Vessels one above another, and fitting airtight into each other, but easily separable. The Chalk with ½ a pint of Water, and a Spoonful or two of Oil of Vitriol, are put into the lowest: The middle one, fill’d with the Water to be medicated, is immediately fix’d in its Neck, that the produc’d Air may rise thro’ the Water: The upper Glass receives the surplus Water forc’d up into it by the Air which takes place in the upper part of the middle Glass. A Figure tho’ not well-drawn, may help a little to explain my imperfect Description.2

A   The Bottom Glass containing the Chalk and Oil of Vitriol in some Water, to produce the Fix’d Air.

B   A Glass Plug, ground into the Bottom of the middle Glass, having within it many small capillary spiral Passages (like the Stem of some Drinking Glasses) thro’ which the Air produc’d forces itself up by its Elasticity, and prevents Water descending.

C   The Water in the Middle-Glass, with the Air rising thro’ it, which being got above it, presses on its Surface at D, and forces some of it through the crooked Pipe up to E, in the Upper Glass.

The Stopper of the Upper Glass has a little perpendicular Groove in one of its Sides, to let out the superfluous Air, otherwise the Glasses would burst.

Three or four new Nails lying at the Bottom of the middle Glass, communicate Iron enough to give the Water a strong ferruginous Taste, and make it turn purple with Green Tea. In 4 or 5 Hours the Water is fit to drink.

The Water in E preserves a Pressure between the Fix’d Air and Water at D, which promotes the Imbibition.

This artificial Pyrmont Water, like the artificial Magnet, is preferr’d to the natural, and for the same Reason, because it is cheaper, may be made stronger, and can be refresh’d at any time with additional Virtue.

I transmitted to our Friend Dubourg at Paris what you transmitted to me for him.3 I have not heard from him lately, but suppose he is well. Wishing you all sorts of Happiness, I am ever, Dear Sir, Your most obedient humble Servant

B Franklin

Dr Rush

Addressed: To / Dr Rush / Philadelphia / per Capt Falconer

Endorsed: Dr. B. Franklin

1Rush had sent to BF and to the well known printers, Charles and Edward Dilly, copies of An Oration, Delivered February 4, 1774, before the American Philosophical Society … Containing, an Enquiry into the Natural History of Medicine among the Indians in North-America, and a Comparative View of Their Diseases and Remedies, with Those of Civilized Nations … (Philadelphia, [1774]); it was dedicated to Dr. Richard Huck, for whom see above, XV, 172 n. In his speech (pp. 52–4, 89–90) Rush inveighed against the tyranny of medical tradition, and even accused the profession of multiplying diseases and increasing their morbidity; physicians should avoid the ridicule of posterity by recognizing how little they know. The Dillys had printed one of the author’s earlier pamphlets (above, XIX, 280 n), and announced this one as “in the Press, and speedily will be published“: London Chron., June 25–28. But they changed their minds, and the pamphlet never was published in England; see Lyman H. Butterfield, ed., Letters of Benjamin Rush … (2 vols., [Princeton] 1951), I, 86 n. Its withdrawal did not have the effect that BF anticipated. Rush had long hoped for election to the Royal Society; if BF and Huck did nominate him, however, he was not elected. David F. Hawke, Benjamin Rush, Revolutionary Gadfly (Indianapolis and New York, [1971]), pp. 96, 111–12, 115.

2For Pyrmont water, and Priestley’s work with “fixed air” that stimulated European chemists, see above, XIX, 125–6 n., 133–4 n, 308 n; and for Dr. Nooth XX, 177 n. A description of the latter’s “nice Apparatus” was read before the Royal Society late in the year and published, with an illustration similar to BF’s if better drawn, in Phil. Trans., LXV (1775), 59–66.

3Rush had sent his pamphlet against slavery, and newspaper accounts of developments in Boston in early 1773: above, XX, 193, 314.

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