Note on Franklin’s Marginalia in Benjamin Wilson, Observations upon Lightning
[After March 21 and before March 30?,4 1773]
Benjamin Wilson was a hardy controversialist. When he lost his case against Franklin in the Purfleet committee in the summer of 1772, he carried it first to the Surveyor General of the Ordnance, then to the Royal Society, and finally to the public by printing his Observations upon Lightning, and the Method of Securing Buildings from It’s Effects, in a Letter to Sir Charles Frederick, &c. (London 1773).5 The Yale University Library has Franklin’s copy of this pamphlet, which he must have read with care; for he marked numerous passages and made several comments. One on p. 23, a mere “Qu[ery],” does not make clear what is being queried; another on p. 48, on the increase in resistance as the number of surfaces increases, is cramped, smudged, and impossible to decipher.6 Only two are both legible and of any significance. At one point Wilson remarked (p. 4 n) that none of the members of the Purfleet committee, when Franklin read them a report of experiments, expressed doubt “of the difference in the effects between pointed and blunt metal [rods] being as 12 to 1”; here Franklin wrote “Attempt to mislead.”7 At another point Wilson concluded (p. 56) that buildings made of fir, containing no metal, were least likely to be struck by lightning; here Franklin wrote “supposing them never wet. Masts of Ships.” These fragmentary marginalia were first jottings, presumably, for the reply to Wilson that he intended to write but never did.
4. The first date is Wilson’s in the preface to the pamphlet. The second is that of BF’s letter to LeRoy below, March 30, in which he said that he intended to write an answer; the intention makes it seem likely to us that he had already examined and marked his copy.
5. See above, XIX, 424–30.
6. BF used a pencil, and the writing has faded; some of it has also been lost in later cropping.
7. For the experiments see idem., loc. cit. and p. 261 and ns. It is not clear in context whether BF was castigating Wilson for attributing the 12:1 ratio to him rather than to Henly, or for twisting the evidence; probably the latter.