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Two Letters from Giambatista Beccaria, [after 11 August 1773]

Two Letters from Giambatista Beccaria

Incomplete drafts: American Philosophical Society

These letters were drafted in reply to Franklin’s of August 11, the preceding document, and were completed at some time between receipt of that letter and early March, 1774.2 Whether Beccaria sent them in draft is not clear, but only the drafts survive; and they pose an editorial problem. His earlier letters to Franklin, which have been variously handled in preceding volumes, were by comparison finished productions and yet, as the editors’ comments indicate, were far from clear.3 The Italian’s convoluted prose is hard to follow even at its best, and electrical disquisitions, as contemporaries complained, turn it into virtually a language of its own.4 A literal translation would be gibberish. A free one is dangerous, even when supplemented by the original text; but we can see no alternative to an English rendering that takes liberty with the Italian in order to convey what we believe Beccaria meant. If we are sometimes mistaken, despite expert assistance,5 we share the blame with the author.

Chiarissimo, e onoratissimo Signore Padrone mio singolarissimo,

Il Signor Fremond mi ha addimandato a vostro nome, se io avea il Tentamen di Epino. Io ho primamente ricevuto tale Libro dal Sig. Sausseure Filosofo genevrino nel 1772, quando stava stampando L’ultimo Libro; nè allora Lo lessi, perchè io era occupatissimo, e mi fidava dell’istoria del Sig. Priestley; solamente giunto a stampare il num. 453 del libro, ovè tratto del esperienza di Richman intorno a’fili annessi ad una Lastra, La cercai in Epino; e fui sorpresso di trovarla in Epino piàplicata, che non è in Priestley, per quanto mi parve allora; che fra le altre cose non intesi, che Epino per la parola catena intendea la communicazione di una faccia della Lastra col suolo.

Ora solo La dimanda del Sig. Fremond mi ha eccitata curiosità sicchè disgiunto le carte del libro di Epino, e lo ho scorso; e universalmente vi ho trovato molto ingegno, e la sorgente vi ho divisata dell’ Ipotesi Geometrica coltivata poi, e migliorata di molto dal Sig. Cavendisch. La chiamo Ipotesi geometrica, perchè a me pare, che non adegui i fenomeni fisici, e che da essi prescinda almanco in parte sollecita unicamente di misurare.

Considerata poi piàentamente la esperienza del Richman, trovo che essa non differisce dalla mia, sè non perchè in quella l’atmosfera della faccia caricata non si dovea estendere alla faccia opposta della Lastra. Epperò io stimereii bene di aggiungere La seguente nota alla parola imperfettissima del sopradetto num: 453.

“Considerata meglio questa sperienza, vedo, che a me riesce piàplicata, perchè l’atmosfera della faccia caricata si estende alla faccia opposta della lastra; che la mia posta talle circostanza è vera; e che tolta tale circostanza, è anche vera quella del Richman.

“Annetto alla stremitàel conduttore l’uncino A d’una boccia ABCDE di lunghissimo collo (Tav. VI; fig. 5); che cosi niuna estrania atmosfera si estende alla pancia della boccia. Poi annetto un elettroscopio al conduttore, che vale il filo annesso da Richman alla faccia caricata della Lamina, e ne annetto un altro all’ armatura esteriore della boccia, che vale il filo annesso da richman alla faccia opposta.

“Allora impugnando io La pancia della boccia, e caricandola vedo, che insorge e cresce la divergenza per eccesso dell’elettroscopio annesso al conduttore per l’eccesso, che ringorga dalla faccia interna della boccia. Nè in tanto si move punto l’elettroscopio annesso alla pancia della boccia, perchè e comunica col suolo, e ad esso non si estende niuna estrania atmosfera.

“Compita la carica, e intralasciato lo stropicciamento del vetro, assai rapidamente insorge la divergenza dell’ elettroscopio annesso alla boccia e scema la divergenza dell’ elettroscopio annesso al conduttore; e si le due divergenze mirano all’egualità. Perchè tolta la forza attuante La carica, le elettricitàontrarie scemano, e mirano all’egualitàon forza proporzionata alla carica indotta; epperò scagliando del fuoco suo l’interna faccia della boccia, e si spingendone via il fuoco del conduttore scema la divergenza dell’ elettroscopio di questo; E traendo del fuoco da ogni parte la faccia esterna, epperò anche dall’elettroscopio annesso, insorge in questo la divergenza.

“Che poi abbandonando a se la boccia le due divergenze scemando restino equali, ciò avviene conformemente alla equalità, a cui mirano le due contrarie elettricità.

“Che toccando alternativamente le pancia della boccia, e il conduttore, alternativamente si abbatta, e insorga (o anche cresca) la divergenza degli elettroscopii, ciò si è spiegato trattando della scarica per alternazione.”

Questa nota, io dicea, mi pare conveniente; ma poi mi pare affatto necessario il cambiamento del penultimo num: 992 del libro, il quale principia: del che la ragione elle è Bisogna che io vaneggiassi quando lo ho scritto; tanto lo trovo scipito. Ecco come mi pare, che debba essere.

992. [In the margin: numeri da sostituirsi] Ed io opino, che questa particolaritàella elettricitàindice negativa della Lastra sola si dicchiari con la seguente considerazione: Che la superioritàcui abbia la elettricitàn una faccia del corpo isolante sopra la elettricitàella faccia opposta, ha efficacia a far comparire la omologa in essa faccia opposta (quella superioritàico ha questa efficacia) proporzionata alla grandezza sua direttamente, e alla carica attuale del corpo inversamente.

Appicco un elettroscopio al conduttore, e uno all’armatura esteriore d’una boccia di lunghissimo collo (Tav: VI, fig. 5.) sicchè l’atmosfera del conduttore non giunga a disturbare l’elettroscopio della boccia; e trovo, che, se stropiccio per pochi momenti il vetro lasciando isolata la boccia, ciò basta perchè l’elettroscopio della boccia acquisti una grande divergenza per eccesso, e la ritenga lungamente. Perchè la carica è nulla, e la superiorita dell’eccesso interiore è grande.

Ma se seguo a stropicciare il vetro, e vo eccitando delle scintille dall’ armatura esteriore della boccia, in verità’elettroscopio segue a ripigliare alcuna divergenza per eccesso, ma la ripiglia ognora minore, e ognora meno rapidamente. Perchè la carica diviene ognora maggiore, e la superioritàcui ha il totale eccesso interno sopra il totale difetto esterno è ognora minore.

Se repplico la sperienza; ma dopo l’eccitamento di ogni scintilla intralascio di stropicciare, la divergenza per eccesso si volge, in tale intervallo, in divergenza per diffetto tanto maggiore, e tanto piàsto, quanto è maggiore il numero delle scintille giàstratte; vale a dire quanto è maggiore la carica giàndotta, e quanto resta minore la superioritàell’eccesso interiore sopra il totale esteriore difetto.

Le cose consentanee accadono nella elettricitàindice universalmente. Quando disgiungo le due lastre AB ab, MN mn (tav: XI, fig. 4) di fresco scaricate, allora nella faccia esteriore di ciascuna appare molto vivace e molto durevole la elettricitàmologa a quella, cui per la elettricitàindice positiva ripiglia la faccia interiore. I Perchè le due lastre appunto sono scaricate; II E perchè le facce interiori ripigliano elettricitàolto vivaci, cospirando l’eccesso insorgente in MN ad avvalorare il difetto insorgente in ab; e reciprocamente.

Quando ignudo una faccia della lastra sola AB ab (Tav: XI, fig, 1.) similmente scaricata di fresco,

Translation

[After Aug. 11, 1773]

Most illustrious and honored Sir, my most particular Master

Signor Fromond asked me from you whether I had Aepinus’ Tentamen. I received the book from Signor Saussure, the Genevan philosopher, in 1772 when I was publishing my latest work; and, because I was extremely busy then, I did not read it but relied upon Signor Priestley’s history. Only when I came to paragraph 453 of my book, where I discuss Richmann’s experiment with the wires attached to a plate, did I look for it in Aepinus;6 where I was surprised to find it more complicated, it seemed to me at the time, than in Priestley, because among other things I did not understand that Aepinus meant by “chain” the connection between one face of the plate and the ground.

Only now has Signor Fromond’s question roused my curiosity, so that I have opened the pages of Aepinus’ work and gone through it. And I have in general found great talent in it, and recognized there the source of the geometric hypothesis that Mr. Cavendish later developed and greatly improved. I call it geometric hypothesis because it is solely concerned with measurement and dose not, in my opinion, take physical phenomena into account but to a large degree disregards them.7

When I later considered Richmann’s experiment more carefully, I discovered that it differed from mine only in that the atmosphere of the charged face did not extend to the opposite face of the plate. Hence I should think that the following note might usefully be appended to the words most imperfect8 in the aforementioned paragraph 453:

“A closer look at that experiment shows me that mine is more complicated, because the atmosphere of the charged face extends to the opposite face of the plate. Given that condition, mine is valid; without that condition, Richmann’s is also valid.

“I connect the hook, A, of a bottle with a very long neck, ABCDE, to the end of the conductor (Plate VI, fig. 5) so that no extraneous atmosphere reaches the interior of the bottle. Then I connect the conductor to an electroscope, which corresponds to the wire Richmann attached to the charged face of the plate, and the outer surface of the bottle to another electroscope, which corresponds to the wire Richmann attached to the opposite face.

“Afterward, as I hold and charge the body of the bottle, I observe that the electroscope connected with the conductor diverges increasingly because of the surplus that flows from the internal surface of the bottle. Meanwhile the electroscope connected with the outer surface does not move at all, both because it communicates with the ground and because no extraneous atmosphere reaches it.

“Once the charging is done and the rubbing discontinued, the divergence of the electroscope connected with the bottle rises extremely fast, and that of the electroscope connected with the conductor diminishes, so that the two tend to equalize. For, once the force producing the charge is removed, the contrary electricities diminish and tend to equalize, with a force commensurate with the induced charge. As the inner face of the bottle projects some of its fire and repels that of the conductor, therefore, the divergence of the latter’s electroscope decreases; and as the outer face loses fire, including that of the connected electroscope, the divergence in the latter rises.

“When the bottle is left to itself the two divergences diminish to the equality to which the two contrary electricities tend.

“Touching the body of the bottle and the conductor in alternation decreases and increases the divergence of the electroscopes. This has been explained in discussing the discharge by alternation.”

This note, as I said, seems to me appropriate. But then a change is needed, in my opinion, in the next to last paragraph, 992, which begins “The reason for this is.” I must have been out of my mind when I wrote it, so senseless does it appear to me. Here is how I think it ought to read:

“992. And this peculiarity of the plate’s negative vindicating electricity9 is, I believe, explained by the following consideration: that the imbalance between the electricity on one face of the insulating body and that on the other face has the effect (I mean the imbalance has this effect) of producing a correspondence in that other face that is directly proportionate to the amount [of the imbalance] and inversely proportionate to the body’s actual charge.

“I connect an electroscope with the conductor and another with the outer surface of a bottle with a very long neck (Plate VI, fig. 5), so that the conductor’s atmosphere does not disturb the bottle’s electroscope. If I rub the glass for a moment, leaving the bottle insulated, this is enough to give the bottle’s electroscope a large divergence by surplus, which it retains a long time. For there is no charge, and the internal surplus is great.

“But, if I go on rubbing the glass and exciting sparks from the bottle’s exernal surface, the electroscope continues to pick up some divergence by surplus, but less and less of it and more and more slowly. For the charge keeps growing, and the imbalance between the total inner surplus and the total outer deficiency grows steadily less.

“If I repeat the experiment but stop rubbing after I have excited each spark, in the intervals [between them] the divergence by surplus becomes divergence by deficiency, at a speed depending on the size and frequency of the sparks obtained, in other words on the size of the induced charge and the degree of imbalance between the inner surplus and the outer deficiency.

“Corresponding phenomena invariably occur in vindicating electricity. When I disconnect the two freshly discharged plates AB ab, MN mn (Plate XI, fig. 4), the electricity on the outer face of each, corresponding to the positive vindicating electricity that the inner face acquires, appears very lively and enduring (1) because the two plates are discharged and (2) because the inner faces acquire very lively electricities as the increasing surplus in MN stimulates the rising deficiency in ab and vice versa.

“When I uncover a single surface of the AB ab plate (Plate XI, fig. 1), likewise freshly discharged [remainder missing].”

Chiarissimo, e Onoratissimo Signore, Padrone mio singolare,

Dopo che mi avete fatto addimandare di Epino, io Lo ho riletto anche la seconda volta, e oltre all’avervi inteso, come giài ho scritto, Lo sperimento di Richman, ho notato particolarmente.

I. Che Epino conoscea, che non v’ha movimento tra’ corpi uno elettrizzato L’altro no. Epper🳯cca ad Epino questa determinazione, cui io attribuiva a me ne’ fogli dell’atmosfera elettrica.

II. Che Epino ha addotto alcuno sperimento dell’Elettricitàindice; v[erbi] g[ratia] di stropicciare una contro L’altra due Lastre guernite di manico isolatore, le quali congiunte non segnano niuna elettricitàdisgiunte segnano elettricitàontrarie. Probabilmente questa sperienza Epino La ha tratta dalla sperienza di Pekino, cui ho addotta nelle sperienze dell’elettricitàindice.

III. Mi è poi piaciuta singolarmente La teoria magnetica Epiniana massime intorno al punto, che il magnetismo s’induce confacentemente alla posizione, cui hanno al sistema magnetic terrestre i corpi, che ne sono capaci. Il magnetismo indotto colla scintilla vi consente.

Universalmente poi l’opera di Epino mi è paruta molto degna. Ma la memoria del Sigr. Cawendisk mi pare superiore massime nel ridurre il valore dell’azione elettrica alla ragione inversa de’quadrati delle distanze molto prossimamente, e nel ridure conseguentemente le elettricitàlle facce de’ corpi.

Ma sinceramente, come io ho giàcritto, non so arrestarmi nella pura attrazione e ripulsione nella parte, che risguarda i fenomeni elettrici derivativi. Il vedere l’atmosfera elettrica, che dalla faccia sovrana del vostro quadro si va grado grado estendendo, e si ripiega sotto a’ margini nudi, e successivamente ne va occupando anche la parte armata dell’inferiore faccia, ed altre si fatte infinite sperienze, mi astringono a riserbare v[erbi] g[ratia] La ripulsione per La forza primitiva del fuoco elettrico.

Un amico mi ha fatto vedere l’articolo XVII dell’appendix to the montly review volume forty seventh pag. 552. Bramerei, che gli deste un’occhiata. La mia vanitài avea voluto persuadere, che a dettare tale articolo abbia avuto parte la gelosia della plebbe, e che La menzogna vi sia entrata per qualche cosa.

Ho letto con piacere gli elogi, che Priestley dàll’elettrometro di Elsmey. Ne ho costrutto uno doppio per ogni modo. I. ABCDE, abcde sono due cartoncini, la figura de’ quali risulta da un rettangolo ACDF, e da due semicerchi ABC, FED. II. Essi cartoncini sono annessi alla sommitàella colonnetta GH sicchè restano paralleli, e distanti alcune linee uno dall’altro. III. La Testa G della colonnetta porta un capelletto di ottone, che regge due fini e mobilissimi perni corrispondenti a’centri v, ed v de’ semicerchi. IV. A’ perni sono annessi i pendoli VP, vp, &c.

Eccone i vantaggi. I. Tra due piani vicini non si dispiega niuna elettricitàe quelle che si dispiegano attorno a’ margini si vogliono supporre eguali. Epperò il movimento de’ pendoli non è disturbato dalla forza dell’elettricitàispiegantesi dall’unico piano di Elsmey; la quale forza mira ad allontanare il pendolo normalmente dal piano; mentre la forza, che ne dee dare la misura mira a muoverlo parallelamente al piano medesimo. II. Uso due pendoli; perchè il confronto delle loro divergenze mi serve di guida a situare l’elettrometro in modo, che sia menomamente disturbato da’ corpi aggiacenti; e anche quando L’elettrometro è situato ottimamente, mi piace di prendere la semisomma delle due divergenze.

Sono parecchi anni, che uso un elettrometro per misurare le picciole elettricitàtmosferiche, per le quali non serve l’elettrometro di Ensnley. Se non temerò di annoiarvi, ve ne manderò La descrizione.

Se mi occorrerài scrivere di cose elettriche far🴮 picciolo ristretto di Epino, e Cawendisk &c.

Io avea scritta questa carta unicamente per memoria di materia da scrivere; ma ora ricevo La lettera d’inbarco delle 500 copie; non ho tempo a riscrivere, nè vuo differire, Epperò perdonate Chiar[issim]o Signore alla improprietàe al disordine di questa lettera. Le copie delle tavole sono 508 tutte unite; inoltre, siccome alcune copie della seconda tavola sono con pocha margine, v’è il supplemento.

La spesa della carta e impronto è di L piemontesi 116 soldi 7½. Non so peranche la spesa della cassa, e del trasporto a Nizza; ne manderò la nota; E se vorrete mandarmi alcuna copia della traduzione (e poche mi basteranno) saro soddisfatto. Sono curiosissimo di sapere se il Signore Priestley ha cercato di avverare un mio sospetto

Translation

[After Aug. 11, 17731]

Most illustrious and honored Sir, my particular Master,

After you asked me about Aepinus I reread him a second time; and in addition to learning from him about Richmann’s experiment, as I already wrote you, I noted in particular:

I. That Aepinus realized that there is no motion between an electrified and an unelectrified body. Hence this discovery, which I ascribed to myself in writing about electrical atmosphere, belongs to Aepinus.

II. That Aepinus has noted an experiment on vindicating electricity, i.e., rubbing together two plates fitted with an insulated handle: they generate no electricity when together, and opposing electricity when separated. Aepinus probably derived this experiment from the Pekin observations,2 which I have cited in my discussion of vindicating electricity.

III. I particularly liked Aepinus’ magnetic theory, above all his point that magnetism is related to the position in the terrestrial magnetic system occupied by bodies capable of being magnetized. Magnetism caused by a spark is no exception.3

Aepinus’ work strikes me in general as of great value. But Mr. Cavendish’s seems to me even better, particularly because it reduces the effect of electrical action very nearly to the inverse of the squares of the distances, and thereby reduces the actions to the surfaces of the bodies.

Frankly, however, in my section on derivative electrical phenomena I cannot stop, as I already wrote you, with mere attraction and repulsion. Seeing the electrical atmosphere spread gradually from the upper face of your square and bend around under the bare margins, and successively fill the coated part of the lower face, and [observing] innumerable other similar experiments that have been made compel me to limit, for instance, the primordial force of the electric fire to repulsion.4

A friend showed me the seventeenth article of the appendix to the Monthly Review, Vol. XLVII [1772], 552[-4]. I should like you to have a look at it. Vanity tries to persuade me that vulgar envy had a hand in the article, and that part of it is untrue.5

I read with pleasure the praise from Priestley for Elsmey’s electrometer. I built a double one.6 I: Two pieces of cardboard (ABCDE, abcde) are each composed of a rectangle (ACDF) and two half-circles (ABC,FED). II: These pieces are attached to the top of the small column (GH) so that they are parallel and a fraction of an inch7 apart. III: The head (G) of the little column has a small brass cap, which bears two thin and extremely flexible pins connecting the centers of the half-circles (V, V). IV: To these are attached the pendulums (VP, vp), &c.

Here are the advantages. I: No electricity is released between planes so close to one another, and what is released from the margins should be considered uniform; hence the motion of the pendulums is unaffected by the electricity coming from Elsmey’s single plane, which tends to drive his pendulum perpendicularly away from the plane, whereas the force to be measured tends to drive it parallel. II: I use two pendulums, because comparing their divergences helps me to place the electrometer where it will be least disturbed by adjacent bodies; and even when it is so placed I take the mean between the two divergences.

For many years I have used an electrometer to measure small amounts of atmospheric electricity, for which Ensnley’s is useless. I will send you a description if it will not bore you.

Should I have occasion to write about electrical matters, I will make a brief summary of Aepinus and Cavendish, &c.

[Postscript?] I had composed this only as a memorandum of things to write about. But I have now received the bill of lading for the 500 copies;8 I have no time to rewrite, and no wish to delay. Hence do forgive, most illustrious Sir, the mistakes and disorder of this letter. The copies of the plates number in all 508; because some copies of the second plate have little margin, extras have been added.

The cost of the paper and handling is £116 7s. Piedmontese. I do not yet know the charge for the box and transportation to Nice; I will send you the bill. I should be glad if you would send me some copies of the translation; a few would suffice. I am most curious to know whether Signor Priestley has tried to confirm a suspicion of mine [remainder missing].

[Note numbering follows the Franklin Papers source.]

2In his reply below, March 20, 1774, BF acknowledged receipt of what appear to have been these two letters. Pace discusses the drafts (op. cit., pp. 59–60, 328) and prints one of them (pp. 376–8); we tend to disagree with him on which was the earlier letter.

3See above, VII, 300–15; XIII, 450–3; XIV, 41–57; XVIII, 108–10.

4He is long-winded and repetitive, said a reviewer of Elettricismo artificiale … [Turin, 1772], and his language “is often obscure, and without the plates would have been unintelligible … from the variety of words and phrases which he has been obliged to adapt, and sometimes to invent, for the explanation of the different phenomena of this new science.” Monthly Rev., XLVII (1772), 554. A decade later Dr. Ingenhousz characterized Beccaria’s style as “dark, diffuse, and perplexed,” calculated to “vex and tire the readers mind, without clearing up the difficulty”; those who extolled his works “had in reality not had the courage to get thro them.” To BF, Aug. 15, 1783; APS.

5From Professor Robert Lopez, who provided us with literal translations, and from Professor Antonio Pace, who gave us generous and much appreciated advice on our freer renderings. Although neither is responsible for the results, we are deeply indebted to both.

6For Fromond see BF’s letter above of Aug. 11, and for de Saussure XIX, 324 n. Aepinus (above, VIII, 393 n) had published his Tentamen theoriae electritatis et magnetismi in St. Petersburg in 1759. Beccaria’s latest work, Elettricismo artificiale, to which the paragraph number refers, was an expansion of his earlier Dell’ elettricismo artificiale, e naturale … (Turin, 1753). The experiment of Georg Richmann, the Swedish scientist, is described in Priestley, History, pp. 337–8.

7For Cavendish’s paper in 1771, which consisted of a series of mathematical propositions and corollaries, see above, XIII, 544 n and Arthur J. Berry, Henry Cavendish: His Life and Scientific Work ([London, etc., 1960]), pp. 92–5.

8Aepinus’ account of Richmann’s experiment, Beccaria had written, “è per lo manco imperfettisima.” The statement was omitted in the translation that was the subject of BF’s letter and of this reply. So was the note that follows and the emendation of Paragraph 992 below, both of which refer to the plates in Elettricismo artificiale.

9Beccaria’s long emendation is marked in the margin, “numeri da sostituirsi,” or paragraphs that should be substituted; he presumably intended to combine them in a single numbered paragraph. For “vindicating electricity” see above, XIV, 49–57, and Beccaria, A Treatise upon Artificial Electricity … (London, 1776), pp. 393–419.

1This letter was also in answer to BF’s of Aug. 11, and internal evidence suggests that it was the later of the two. It exists in two incomplete drafts, of which we have printed the longer; the shorter contains the same first four paragraphs in slightly abbreviated form, and then adds a sentence that is not in the other: “Quando io ho scritto di athmosfera elettrica nel 17[..], e mi sono attribuito le scoperta di quella parte di legge, io ignorava affatto, che altri ne avesse scritto, nemmeno avea veduto le vostre sperienze attorno all’ atmosfera de’ cannoni.” “When I wrote about atmospheric electricity in 17[..] and attributed to myself the discovery of some of its laws, I was quite ignorant that others had written about it; and I had not heard of your experiments with the atmosphere of tubes.” Beccaria was presumably referring to his work in 1753. BF’s experiments were actually performed in 1755; see above, V, 516–19.

2Made by Jesuits in Pekin, forwarded by them to the Imperial Academy in St. Petersburg in 1755, and published in its transactions. See Beccaria’s Treatise cited above, p. 404; above, XIV, 49 n.

3Beccaria seems to be referring to the effect of a spark on changing the magnetic direction of a needle, a point that he discusses in idem., pp. 306–7. The translator of the Treatise appended a note on that passage that is also relevant to this one: “If the above paragraph, on the contents of which the author seems to lay a particular stress, had been more clearly expressed in the original, the translation of it would also have been somewhat clearer.”

4All that is apparent in this passage, at least to us, is that Beccaria was referring to what he called the “Franklin square,” a sheet of glass coated on both sides with lead, with which he had experimented; see the Treatise, p. 76. BF’s description of the square is above, III, 356–7.

5The reviewer, in addition to the comments quoted above on Beccaria’s style, suggested that his work was largely derived from experiments in England, where the apparatus was more sophisticated and the scientists were further advanced than in Italy.

6Priestley’s account of the electrometer is printed above, XVII, 259–63. Beccaria changed “Elsmey” later in the letter to “Ensnley”—an advance toward his goal of Henly, which his translator finally achieved in the Treatise, p. 444 n. The MS sketch of the electrometer is in Pace, op. cit., p. 377.

7In “alcune linee” Beccaria presumably had in mind some multiple of the Paris line, a unit of measurement that was slightly less than a tenth of an inch.

8Beccaria was responding to BF’s request, in his letter above of Aug. 11, for engravings to illustrate the translation. See BF’s reply below, March 20, 1774.

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