Benjamin Franklin Papers

From Benjamin Franklin to Jan Ingenhousz, 30 September 1773

To Jan Ingenhousz

ALS (letterbook draft): American Philosophical Society

London, Sept. 30. 1773

My dear Friend,

I rejoic’d as much as any Friend could do, at the News we receiv’d here from time to time of your Successes in your Profession, and of the safe Recovery of your illustrious Patients of that most amiable Family:1 But it griev’d us all at the same time to hear that you did not yourself enjoy Health in that Country. Surely their known Goodness will graciously give you Leave of Absence, if you have but the Courage to request it, and permit you to come and reside in England, which always agreed well with your Constitution. All your Friends here will be made happy by such an Event.

I had purposed to return to America this last Summer, but some Events in our Colony Affairs, induc’d me to stay here another Winter. Sometime in May or June next I believe I shall leave England. May I hope first to see you here once more?

I shall be glad to see the Work of Abbé Fontana on that Disease of Wheat.2 As yet I have not heard that it is come to England.

Sir W. Hamilton writes from Naples, that after many Experiments, he has not been able to perceive any certain Signs of Electricity in the Torpedo. It is perhaps best that there should be two Opinions on this Subject: for that may occasion a more thorough Examination of it, and finally make us better acquainted with it.3

It is not difficult to construct a Needle so as to keep pointing to the Meridian of any one Place, whatever may be the Variation in that Place. But to point always to the Meridian wherever the Needle may be remov’d, is I apprehend not possible.4

Mr. Nairne, has, as you have heard, finished a very fine Electric Machine. I have seen Sparks from the Prime Conductor 13 Inches in length. He has added a large Battery, and produces a Discharge from it sufficiently strong to blast growing Vegetables, as Lightning is suppos’d to do. From a greater Force used, perhaps some more Discoveries may be made.5 I am much pleas’d with the Account you give me of your new Machine of white Velvet rubbed upon Hareskin.

Last Year the Board of Ordnance apply’d to the Royal Society here for their Opinion of the Propriety of erecting Conductors to secure the Powder Magazines at Purfleet. The Society appointed a Committee to view the Magazines and report their Advice. The Members appointed were Messrs. Cavendish, Watson, Delavall, Robertson, Wilson and myself. We accordingly after viewing them drew up a Report, recommending Conductors to each, elevated 10 feet above the Roof, and pointed at the Ends. M. Delavall did not attend, but all the rest agreed in the Report, only M. Wilson objected to pointing the Rods, asserting that blunt Ends or Knobs would be better. The Work however was finished according to our Direction. He was displeas’d that his Opinion was not followed, and has written a Pamphlet against Points.6 I have not answered it, being averse to Dispute. But in a new Translation and Edition of my Book printed lately at Paris, 2 Vols. 4to., you will see some new Experiments of mine, with the Reasonings upon them, which satisfy’d the Committee. They are not yet printed in English, but will in a new Edition now printing at Oxford; and perhaps they will be in the next Transactions.7

It has been a Fashion to decry Hawkesworth’s Book: but it does not deserve the Treatment it has met with. It acquaints us with new[?] People having new Customs; and teaches us a good deal of new Knowledge.8

Capt. Phips is returned, not having been able to approach the Pole nearer than 81 Degrees, the Ice preventing.9

M. Fremont, an ingenious young Italian who was lately here, gave me a little Spy Glass of his Making upon Pere Boschovich’s Principles, the Ocular Lens being a composition of different Glasses instead of the Objective.1 It is indeed a very good one.

Sir John Pringle is return’d from Scotland, better in Health than heretofore. He always speaks of you with Respect and Affection: as does Dr. Huck2 and all that knew you. I am ever, with the sincerest Esteem, Dear Sir, Your faithful and most obedient Servant


Dr Ingenhausz
Wrote at W.W. for next week3

[Note numbering follows the Franklin Papers source.]

1For the Doctor see above, XIV, 4 n. At this time he was in Vienna as physician to the imperial family. BF, it is clear from later passages in this letter, was answering one from him that is now lost.

2Felice Fontana, Osservazioni sopra la ruggine del grano … (Lucca, 1767). For Abbé Fontana (1730–1805), a distinguished naturalist and physiologist, see the Enciclopedia italiana de scienze, lettere ed arti … (36 vols., [Rome], 1929–39).

3Ingenhousz, as BF undoubtedly knew, was interested in torpedo fish, and on a visit to Leghorn had captured some, held them in his hand, and felt the shocks they gave. He wrote Sir John Pringle on Jan. 1, 1773, about this experience, and the letter was published in Phil. Trans., LXV (1775), 1–4. Sir William Hamilton had been experimenting with the torpedo earlier in the year; see de Saussure to BF above, Feb. 23.

4This paragraph is puzzling because it seems to belabor the obvious. BF must be referring to the variation of the compass needle from the true north (“the Meridian”), a phenomenon that had long been under investigation as part of the attempt to determine longitude exactly. In his missing letter Ingenhousz may have suggested constructing some instrument that, wherever located, would correct for this variation; impossible, BF seems to be saying, because the angle of variation is never the same. But this scarcely needed pointing out to Ingenhousz, who was no tyro; see his paper on magnetic needles in Phil. Trans., LXIX (1779), part 2, 537–46. Contemporary methods of computing variation are discussed in Charles Hutton, A Mathematical and Philosophical Dictionary … (2 vols., London, 1795), II, 637.

5BF is referring to the electrical machine and battery that Edward Nairne, the instrument-maker, had built and subsequently described in the Phil. Trans. The machine may have been a simplified and improved version of one that he had already made, on Priestley’s design, for the Grand Duke of Tuscany; but the new design was clearly his own, and not the one he described in his Directions for Using the Electrical Machine … (London, 1774). On Sept. 14, 1773, he used the machine “to blast growing Vegetables.” Phil. Trans., LXIV (1774), part I, 79–82, 85–7; Jack Lindsay, ed., Autobiography of Joseph Priestley … ([Bath, 1970]), p. 96. BF, who may have attended this demonstration, looked forward to further discoveries because Nairne’s machine was the best means yet found to simulate lightning.

6See above, our note on BF’s marginalia, after March 21, and XIX, 260–2, 429–30.

7The French translation was in Dubourg, Œuvres, I, 289–301; the English version is above, XIX, 244–55. The experiments did not appear in the Phil. Trans., as far as we can discover, or in the 5th ed. of Exper. and Obser. (London, 1774).

8BF’s friendship with the publisher and the author may have influenced his opinion. In June William Strahan had brought out John Hawkesworth’s An Account of the Voyages Undertaken by the Order of His Present Majesty for Making Discoveries in the Southern Hemisphere … (3 vols., London, 1773). The volumes were a compilation of the various explorers’ accounts, reworked by the compiler and written in the first person. Critics complained of this device, among other things, because Hawkesworth intruded himself: “the usual plain texture of the nautical narrative suddenly disappears, by the insertion of some splendid philosophical patches of a very different manufacture.” Monthly Rev. …, XLIX (1774), 138; see also the Gent. Mag., XLIII (1773), 286–90; London Chron., July 10–13, 1773. The best modern description of the genesis and reception of the work is in John C. Beaglehole, The Life of Captain James Cook (Stanford, Cal., [1974]), pp. 290–1, 439–40, 457–9.

9For the voyage commanded by Capt. the Hon. Constantine Phipps see BF to LeRoy above, March 30. One of the purposes of the expedition was to test instruments for measuring longitude; BF may therefore have assumed that Ingenhousz would be interested in the outcome.

1For Fromond, the young Lombard scientist, and his English visit see BF to Beccaria above, Aug. 11. The famous Jesuit mathematician and astronomer, Ruggiero Giuseppe Boscovich (1711?–87), is said to have recommended Fromond to BF; see Antonio Pace, Benjamin Franklin and Italy (Philadelphia, 1958), pp. 35–6, where the nature of the “little Spy Glass” is explained.

2Dr. Richard Huck had been an acquaintance of BF for at least five years: above, XV, 172 n.

3BF’s note to himself, we suppose, to indicate that the letter was drafted at West Wycombe, to be finished in London the next week. The letter to Percival below, Oct. 15, was similarly drafted at Lord Le Despencer’s on Sept. 25.

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