From Benjamin Franklin to Giambatista Beccaria, 29 May 1766
To Giambatista Beccaria
MS not found; retranslated from a translation into Italian printed in Guiseppe A. F. G. Eandi, Memorie istoriche intorno gli studi del padre Giambatista Beccaria delle Scuole Pie professore difisica sperimentale nella R. Università di Torino ec. (Torino, 1783), pp. 146–8.7
London, May 29. 1766.
Reverend Sir,
It gives me pleasure to transmit to you herewith the thanks of our society for your most ingenious paper on electrical matters,* and permit me to add to them my own [thanks].
In conformity with your wishes, it had been shown to me before it was presented to the society, and I recommended it as well deserving the society’s attention.
Before it is printed in the Transactions I should like to know whether there is not some mistake in that part of the table where you say:
Pili leporis accipiunt a tibiali albo pauculum;
and then: Tibiale album dat pilis leporis plurimum;
and following: Tibiale album accipit a tibiali nigro pauculum;
next: Tibiale nigrum dat tibiali albo plurimum.†
If these are not writing mistakes, but agree with facts, I should like to know what circumstances in the experiments you think may account for [the fact] that in the reciprocal rubbing1 of those substances one of them does not supply the same quantity as the other receives.
I ought to have thanked you before now for the favor you did to me some time ago by sending me your books on electrical matters, and for your mentioning me honorably in them.2 Rest assured that I have read no other work on this subject that has given me so much pleasure. A new edition of my writings, with many additions, is being printed here; when it is finished I shall beg you to accept a copy.3 A small paper on meteorology which was read to the society some time ago, but not yet printed in the Transactions, is appended to it.4
Since I came back here from America in 1765 I have found only one new thing about electricity: this is that, if a spark is sent into the dark around bodies which imbibe light5 (as I believe I must express myself), these bodies shine briskly for a few minutes thereafter. It is not necessary for electric fire to go through the body; a spark that passes at a two- or three-inch distance is sufficient. I suppose that Bologna6 stone may be used for this experiment. Here we use an artificial compound of calcined oyster shells, burned in a crucible with sulphur.7 A spark of your fulminating table8 would give a long lasting light. I am sending you a small piece of wood covered with a little of this compound, which was given me, and made by Mr. Canton, a member of our society. The discoverer of this effect of electricity was Mr. Lane,9 who also has devised an elegant method, by means of a screw, to give exactly equal shocks of a certain determined strength for medical objects, as the bottle will always discharge when it has received the quantity of fire that will hit at the distance determined by the screw.
I am pleased to hear that you read English, although you do not write it. I am in the same case with Italian. Hence we can correspond, if this pleases you, more easily if each of us writes his own language. I shall thus more often take the opportunity of expressing to you through my letters the great esteem, and the respect, with which I am, Reverend Sir, Your most obedient and most humble servant
B. Franklin.
7. The editors are grateful to Robert S. Lopez, Durfee Professor of History, Yale University, for making the retranslation printed here. Another retranslation, taken from the same Italian text, is in Smyth, Writings, iv, 457–9. Footnotes below call attention to the only two significant differences between these retranslations. The translator of the original English text into Italian was Count Prospero Balbo.
8. Beccaria’s paper, read before the Royal Society on May 1, 1766, was published, with the Latin title printed here, in Phil. Trans., lvi (1766), 105–18.
9. That is, the unitalicized Latin words at the ends of BF’s second, third, and fourth quotations were erroneous and do not appear in either of the eighteenth-century printed texts of the paper.
1. The Italian of this phrase is nel vicendevole stropicciamento, which Smyth renders as “in the alternate friction.”
2. For the books and papers Beccaria sent to BF, see above, V, 395; VII, 300, 315. For an earlier letter of thanks, see above, X, 126.
3. This appears to be BF’s first mention of the fourth edition of his Experiments and Observations on Electricity, presumably then in the early stages of preparation. Although it bears a 1769 imprint, it was published Dec. 5, 1768. London Chron., Dec. 1–3, 3–6, 1768.
4. Above, IV, 235–43.
5. The Italian here is “che s’ imbevono di luce,” which Smyth renders as “that live by light.” Eighteenth-century discussions of the phenomenon discovered by Lane and referred to here suggest that the bodies in question were those with the attribute of luminescence, and more particularly of fluorescence or phosphorescence.
6. A variety of the mineral barite, first discovered near Bologna; it is phosphorescent when calcined.
7. John Canton described the production of this compound in Phil. Trans., lviii (1768), 337–44.
8. In his paper for the Royal Society Beccaria described this contrivance, calling it “abacus fulminans.” Phil. Trans., lvi (1766), 115–16.
9. Timothy Lane (c. 1734–1807), F.R.S., and one-time master of the Apothecaries’ Company. Priestley described Lane’s experiment in The History and Present State of Electricity (London, 1767), pp. 312–13, but Lane seems never to have reported it in print.