To Benjamin Franklin from Edward Nairne, 2 December 1783
From Edward Nairne
ALS: American Philosophical Society
Lond Decr 2: 1783
Dear Sir
I received your favours.7 The book & prints which Mr Argand was so obliging as to deliver I have since sent to Sir Joseph Banks agreable to your request.8 I am very much obliged to you for your observations on the alteration of the wood of the box belonging to the magnets. Since I received your favour have been endeavouring to make as simple an instrument as possible, a drawing of which I have here sent. If you should at your leisure consider it & if you find that its not adequate to the purpose wanted should esteem it as a great favour if you’d inform me of it or if any Alterations or additions can be added to it. I was the day before yesterday at Windsor where Mr De Luc shewed me an Hygrometer it was made of a thin peice of whale bone about nine inches long was kept strait by a line fasten’d to it going over a pulley the other end of which line was fastned to a spiral spring. He observed that it was the only substance he had ever met with that would always return to the same length when soaked in water. It altered in its length about one inch from extreame Moisture to extream dryness.9 A Day or two ago Mrs Clark called on me. She desired her duty to you when I wrote & desired I would inform you she had lost her only Brother in the Ville de Paris.1
Mrs Nairne Polly & Fanny desire to be particularly remembred to you. Hope you enjoy a good state of health as they at present do, they were not a little flattered that you mentioned them in your letter. I sent you sometime ago the account of shortning wire by Lightning which I hope you have received. Mr Magellan under took to have it sent to you.2
I am Dear Sir Your most obliged Hble servt
Edwd: Nairne
The explanation of the under drawing.3 Fig 1 A a peice of wood about 12 Inches long & 2 inches broad cut cross wise the grain of the wood which slides freely between the two peices of wood BB forming groves for it. C Is a screw [for adj]usting4 the peice of wood A so that the index [may] point to the proper division when first made. In Fig 2. a. Is a slit to admit the pin e to move [freely,] which pin by being fast in the peice of wood A moves with it as it shortens or lengthens and by pressing against the short end of the Index D causes it to move up or down according as the weather is moist or dry which is shewn on the Divided arch at the end of the instrument.
Addressed: A Monsr / Son Excellence le Dr. F[ranklin] / a Passy / pres / Paris
7. BF’s letter of Oct. 18 and its enclosure, a letter on hygrometers.
8. Argand may have carried a letter of introduction from BF to Nairne, as well as material for Banks; see Le Roy to BF, [Oct. 26?], above.
9. The whalebone hygrometer of Jean-André Deluc (XX, 78n) rivaled that of Saussure, which the latter described in the work he sent BF on Oct. 10 (above); see Dictionary of Scientific Biography under Deluc. For a description of the instrument see J. A. De Luc, “A Second Paper on Hygrometry,” Phil. Trans., LXXXI (1791), 389–[423].
1. Anne Johnson Clarke, BF’s grandniece, informed him herself on March 2, 1784 (APS). The Ville de Paris sank in 1782.
2. If it arrived, BF’s copy has not been located. This was most likely Nairne’s letter to Sir Joseph Banks, for which see XL, 470n.
3. Nairne’s drawings of figures 1 and 2 are no longer with the letter. We suspect that he sketched them below this legend, as the bottom third of this sheet has been largely cut away. Copies of them, however, are reproduced in Jefferson Papers, XI, 76–7, with a nearly identical legend: Nairne had made copies for Benjamin Vaughan, who in turn sent copies to TJ in 1787 when explaining his own realization of BF’s proposed hygrometer.
4. The right margin of the MS has a tear affecting three lines of text. We supply our readings from the legend published in Vaughan’s letter to TJ cited above.