It was inevitable that Franklin’s theories of electricity should meet with opponents and detractors. The most prominent of these was the Abbé Nollet, the principal electrician of France, whose theories Franklin’s controverted and whose authority Franklin’s Experiments and Observations threatened. Nollet defended his views and attacked Franklin’s in Lettres sur l’Electricité; and for some time thereafter electricians divided into Franklinists and anti-Franklinists.7

Charles Dufay had demonstrated that there are two kinds of electricity, which he called vitreous (made by rubbing glass, rock crystal, wool, jewels, and animals’ hair and fur) and resinous (made by rubbing amber, silk, thread, and paper); and that each would attract the other, but repel the like kind. In 1746 Nollet, who had succeeded Dufay in reputation and influence, in his Essai sur l’Electricité des Corps named the two kinds of electricity effluent and affluent. By this he meant that electric fluid is constantly streaming out of an electrified body and as constantly streaming in through pores, which he imagined must exist in every object.8 The theory provoked controversy in Europe, and Nollet defended and amplified his views in Recherches sur les causes particulières des phénomènes électriques in 1749. This was the situation when Franklin’s hypothesis of positive and negative states of one electric fluid appeared in his Experiments and Observations, published in London in 1751.

At the suggestion of Buffon, keeper of the Jardin des Plantes, Franklin’s book was translated by Thomas-François Dalibard, a botanist and geologist who had become interested in electricity and taken Delor’s course in the latter’s house in the Place de l’Estrapade. To his translation Dalibard added an address to the reader and a short history of electricity, 90 pages in all, in which he did not even mention Nollet. This appeared early in 1752. On February 3 of that year Buffon, Delor, and Dalibard repeated Franklin’s experiments at the country place of the Duc d’Ayen at St. Germain-en-Laye, with such success that they determined to test his hypothesis of the identity of lightning and electricity. This was done in the famous experiment at Marly-la-Ville, May 10; and three days later Dalibard reported it to the Académie des Sciences in Paris (see above, p. 302). He presented a supplementary report on July 5, concluding that lightning and electricity are indisputably identical. Though Delor and Dalibard failed in their attempt to repeat the experiment on June 7, a successful repetition was performed by Le Monnier at St. Germain-en-Laye shortly afterwards.

“L’abbé meurt de chagrin de tout cela,” Buffon wrote a little maliciously to a friend. Nollet might well do so. After all, his work had been totally ignored in Dalibard’s history of electricity, he was receiving no credit for his earlier suggestion that lightning and electricity might be the same, and the experiment to prove the point had been conducted without his knowledge, advice, or presence. On May 17 in a representation against Dalibard’s report he asked the Academy to postpone publication until further confirmation could be obtained, and demanded that his own priority be recognized in any publication approved by the Academy. On July 1 the Academy decided to postpone publication of both Dalibard’s memoir and Nollet’s representation. Meanwhile a commission of the Academy examined Nollet’s journal and reported unanimously on August 23 that they had witnessed the experiments recorded in it and that the results appeared to be as reported there. On September 6 the Academy ordered that Dalibard’s second memoir should also be postponed.

Meanwhile Nollet prepared a defense of his theories and questioned Franklin’s in a series of nine essays in the form of letters, six of them addressed to Franklin. The book was published about January in 1753.9 Nollet raised some important questions, but in general refused to recognize the possibility that Franklin was correct. He gave the American little credit for originality, and his tone was almost everywhere offensively condescending. The main points of these letters are summarized below. Nollet’s book is not reprinted in full since the papers are letters in form only and Franklin did not reply to them.

Letter I. To Maria Angelo Ardinghelli.1 “Contenant l’Histoire des Découvertes qui se sont faites, sur l’Electricité dans le courant de l’Année 1752,” pp. 1–23. Most of the experiments reported in Franklin’s Experiments and Observations have already been published in Europe; but Nollet does not charge Franklin with plagiarism: it was only likely that a man of the New World, engaged in business, might not know what was happening in Europe or receive European books. Franklin had proposed the lightning rod, but had not erected one: was this because there were no thunder storms in Philadelphia or because he was sufficiently aware of the reasons why the experiment would fail and so did not take the trouble to make it? Dalibard had performed it, drawing sparks from clouds, at Marly-la-Ville on May 10; and Delor did likewise in Paris a few hours later. But Nollet insists that Franklin’s proposal to draw the destructive power of lightning from clouds by rods is erroneously founded. Only five or six months before, the identity of lightning and electricity was a conjecture; thanks to Franklin and others who shared his views it now appeared to be an incontestable truth.

Letter II. To Benjamin Franklin, July 1, 1752. “Qui doit servir d’introduction à celles qui suivent,” pp. 24–38. As no mention was made of him by Franklin in the Experiments and Observations2 or by Dalibard in his “Histoire abrégée” prefixed to the French translation, Nollet identifies himself as an electrical experimenter who began his work after M. Dufay and before the Germans, and cites his Essai sur l’Electricité, 1746, and Recherches sur les causes particulières des phénomènes électriques, 1749, of which he is sending copies to Franklin. All Nollet’s explanations of electrical phenomena are based on the principles of simultaneous effluence and affluence. Effluent matter flows out of every part of an electric body; affluent matter, which is similar, comes into the electric body by all means from the atmosphere and nearby bodies; and these two currents flow at the same time, though in opposite directions. This theory is supported by other physicists; Nollet invites Franklin to repeat his (Nollet’s) experiments, and he wants further information from Franklin before accepting the latter’s theory. Some of Franklin’s experiments, hailed by his English and French publishers as new discoveries, had already been performed in Europe; perhaps because of his remoteness from Europe, Franklin was unacquainted with them.

Letter III. To Benjamin Franklin. “Sur la nature de la matière électrique,” pp. 39–59. On the subject of the analogy between electricity and common fire, Nollet thinks Franklin must be displeased that his editors have said of him that he “exhibits to our considerations, an invisible, subtle matter, disseminated through all nature … which has escaped our observations”;3 for this had in fact been recognized and has long been recognized as a powerful force which kills animals and pierces both hard and fragile bodies. Franklin’s first three letters led Nollet to think he was in perfect agreement with other physicists on the nature of electrical matter; but when in the fourth Franklin distinguished electric fire from common fire (see above, III, 374–5), he took a different line from them. That there was such a difference Franklin has not proved. Nollet also rejects Franklin’s theory of cold fusion (see above, III, 375–6) and his assertion that glass is impermeable to electricity (see above, p. 25). In short, the notion that there are two kinds of fire is unsupported by experiment or by logical or plausible arguments; it is only a hypothesis.

Letter IV. To Benjamin Franklin. “Dans laquelle on prouve que le verre n’est point imperméable au fluide électrique,” pp. 60–82. Nollet describes several experiments which in his opinion prove that glass is permeable by electricity. He offers an explanation of Franklin’s “magical picture” experiment (see above, III, 358–9).

Letter V. To Benjamin Franklin. “Sur différents faits concernants l’expérience de Leyde,” pp. 83–128. Nollet asserts that Franklin’s conclusions about the Leyden jar differ from his and those of other European electricians. Specifically challenging Franklin’s reasoning and methods, he rejects Franklin’s conclusions that: 1. the power of giving an electric shock rests solely in the glass of the jar and not in the water (see above, III, 356); 2. the Leyden jar loses as much electrical fire from one of its surfaces as it receives from the other (see above, III, 354); 3. when one surface of a charged jar loses its electrical fluid, the bottle cannot regain equilibrium except by an exterior communication (see above, III, 356); 4. a Leyden jar is discharged through the same outlet by which it was charged (see above, III, 353). Nollet asserts that many of the phenomena for which Franklin’s explanations are inadequate can be explained by the doctrine of effluence and affluence, “which is not a system, but a well proved fact.” Nollet invites Franklin to repeat his own experiments and to examine Nollet’s.

Letter VI. To Benjamin Franklin. “Sur le pouvoir des Pointes,” pp. 129–53. Nollet believes Franklin has overstated the case for the power of points. He asks: 1. how, if the electrical atmosphere is regarded as a tranquil fluid resting everywhere on the surface of the electrical body and taking a shape like the body, Franklin explains electrical wind; 2. how, if these atmospheres surround electrised bodies by the attraction the latter exert, they can be five or six feet in extent, as Franklin recognizes; and he questions the assertion that points have the property of both attracting and repelling electrical fluid. Nollet is still sure that what is called the power of points does not belong precisely and only to points; the effects they produce may also be owing to the surfaces between the pointed ends of a body.

Letter VII. To Benjamin Franklin. “Sur l’analogie du Tonnerre avec l’Electricité,” pp. 154–97. Dalibard and Delor have performed the experiment which Franklin conceived. The notion that lightning and electricity are identical has often been proposed before, by Nollet and others; but the Marly experiment proves that they are two effects of the same principle. Can Franklin really believe that lightning is now in men’s control? What evidence is there that a lightning-charged cloud large enough to cover a city, will be emptied in a few minutes by means of a rod or metal wire no larger than a finger? Anyone who would credit such an idea would propose preventing floods by inserting small tubes into the banks of streams. If points were enough, would not clock towers serve? Nollet proposed an apparatus to test the character of lightning and ring bells by its power.4 He regards as mere invention and ingenuity Franklin’s concept about clouds of the sea and of the land, electrised and nonelectrised; and examines §§ 11–23 of Franklin’s fourth letter (see above, III, 367–9). In conclusion he invites Franklin to correspond with him.

Letter VIII. To M. Jallabert,5 pp. 198–223. Nollet sends a copy of the French translation of Franklin’s Experiments and Observations and a copy of the Abbé Maugin’s Histoire générale et particulière de l’électricité. Jallabert will be pleased with them, but should know that most of the experiments have been previously performed elsewhere.

Letter IX. To M. Boze.6 “Dans laquelle on expose les raisons qui ont pû retarder les nouvelles découvertes dont il a été question dans les Lettres précédentes,” pp. 224–40. Replies to Boze’s letter of July 20; advises him to read Franklin’s Experiments in the original English.

“Expériences faites en presence de Messieurs Bouguer, de Montigny, de Courtivron, d’Alembert and le Roi, Commissaires nommés par l’Académie,” pp. 241–62. A record of experiments made by Nollet, June 14–August 29, 1752.

Nollet’s defense could not be ignored. William Watson gave an account of its contents to the Royal Society, May 13, 1753, without discussion or criticism, so that he seemed to receive Nollet’s views favorably, though he had formerly claimed he anticipated Franklin’s theories.7 In Philadelphia Franklin repeated the Abbé’s experiments and discovered that some results were quite different from what Nollet had reported and that all could be explained completely by his own principles. He began to prepare “a civil Letter” in reply, but decided against it when others came to his defense.8 One of these was Father Beccaria of Italy; another was the son of his old friend Cadwallader Colden.9 But Nollet’s conduct and tone rankled, and Franklin referred to the incident from time to time, even thirty years afterwards, as an example of what pride and stubbornness can lead a scientist into.1 When he visited Paris in 1767 the two men did not meet.