Research for this paper was supported by a grant from the Australian Research Grants Committee. I am grateful to Maurice Crosland, Ivor Grattan-Guinness and Jim Cross for comments on an earlier draft.

¹ Poisson, , ‘Mémoire sur la théorie du son’, Journal de L'École Polytechnique, 7 (1808), 319–392.Google Scholar Cf. the judgement of Lamb, Horace, The Evolution of Mathematical Physics (Cambridge, 1924), p. 9.Google Scholar

² Poisson, , ‘Mémoire sur la distribution de l'électricité à la surface des corps conducteurs’, Mém. de l'Institut, 12 (pt. 1), 1–92Google Scholar; ‘Second mémoire sur la distribution de l'électricité à la surface des corps conducteurs’, ibid., 12 (pt. 2), 163–274.

³ Crosland, Maurice, The Society of Arcueil: A View of French Science at the Time of Napoleon I (London, 1967).CrossRefGoogle Scholar

⁴ Fox, R., ‘The Rise and Fall of Laplacian Physics’, Historical Studies in the Physical Sciences, 4 (1974), 81–136.CrossRefGoogle Scholar

⁵ Grattan-Guinness, I. with Ravetz, J. R., Joseph Fourier 1768–1830 (Cambridge, Mass., 1972)Google Scholar; Grattan-Guinness, , ‘Mathematical Physics in France, 1800–1835’, pp. 349–370Google Scholar in Jahnke, H. N. and Otte, M., eds., Epistemological and Social Problems of the Sciences in the Early Nineteenth Century (Dordrecht, 1981)CrossRefGoogle Scholar; idem., ‘Mathematical Physics in France 1800–1840: Knowledge, Activity and Historiography’, pp. 95–138Google Scholar in Dauben, J. W., ed., Mathematical Perspectives: Essays on Mathematics and Its Historical Development (New York, 1981)Google Scholar; idem., ‘Recent Researches in French Mathematical Physics of the Early 19th Century’, Annals of Science, 38 (1981), 663–690.Google Scholar

⁶ Frankel, Eugene, ‘Career-Making in Post-Revolutionary France: The Case of Jean-Baptiste Biot’, British Journal for the History of Science, 11 (1978), 36–48.CrossRefGoogle Scholar See also idem., ‘J. B. Biot and the Mathematization of Experimental Physics in Napoleonic France’, Historical Studies in the Physical Sciences, 8 (1977), 33–72.Google Scholar

⁷ See, however, the recently-published volume marking the bicentenary of his birth, Siméon-Denis Poisson et la science de son temps, ed. Métivier, M. et al. (Paris, 1981).Google Scholar

⁸ Libri, G., ‘Lettres à un américain sur l'état des sciences en France. III: M. Poisson’, Revue des deux mondes, ser. 2, 23 (1840), 410–437, p. 412.Google Scholar Arago, drawing ostensibly on Poisson's own testimony, does not mention fainting, but in a similar vein stresses Poisson's distaste for the career that had been chosen for him (Arago, , ‘Poisson’, Oeuures complètes, II [Paris, 1854], 593–698.Google Scholar

⁹ Arago reports that Poisson was actually ready to take the examination a year earlier, but was prevented by ill health from doing so (Arago, , op. cit., p. 598).Google Scholar

¹⁰ Libri, , op. cit., p. 416.Google Scholar

¹¹ Ibid., pp. 415, 417. Their paper was published in J. École Polytechnique, 4 (11th cahier), an X, 170–172.Google Scholar

¹² Académie des Sciences, Procès-verbaux des séances de l'Académie tenues depuis la fondation jusqu'au mois d'août, 1835 (10 vols., Hendaye, 1910–1922), II, 277, 283Google Scholar; J. École Polytechnique, 4 (11th cahier), an X, 173–181.Google Scholar

¹³ Fourcy, A., Histoire de L'École Polytechnique (Paris, 1828), p. 272Google Scholar; Libri, , op. cit., p. 418.Google Scholar Poisson was living at this time with Jean Guillaume Garnier, who ran a preparatory school for students intending to sit the entrance examination for the École Polytechnique in addition to serving as suppléant for Fourier, absent in Egypt with Bonaparte's famous expedition, at the École itself. Poisson did some of the teaching at Garnier's school in return for board and lodging (cf. Fourcy, , op. cit., p. 154Google Scholar, and Garnier's autobiographical notes, published in Quetelet, A., ‘Notice sur Jean Guillaume Garnier (1766–1840)’, Annuaire de L'Acad. Roy. de Bruxelles, 1841, pp. 161–207; p. 171.Google Scholar Garnier claims to have been acting also as professeur adjoint to Lagrange during the period 1798–1802, but Fourcy does not mention this, and the story seems impossible anyway since Lagrange retired in 1799 and was replaced by Lacroix). Poisson is reported also to have been receiving financial support during these years from the well known social philosopher Henri de Saint-Simon (Crosland, , The Society of Arcueil, p. 91).Google Scholar

¹⁴ Ibid.: ‘Véritablement, cela vous était dú’. Garnier reports with considerable bitterness how, though Fourier had promised him the succession to his chair, Laplace had intervened to have Poisson appointed to the position instead (Quetelet, , op. cit., p. 172).Google Scholar

¹⁵ Procès-verbaux, III, 211, 222, 303–305, 563, 594–597.Google ScholarArago, , History of My Youth, trans. Powell, Baden (London, 1855), p. 19.Google Scholar

¹⁶ Ibid., II, 640, 642.

¹⁷ Costabel, Pierre, art. ‘Poisson’ in Dictionary of Scientific Biography, XV, 480–490.Google Scholar

¹⁸ Arago, , op. cit., pp. 603–604.Google Scholar

¹⁹ Procès-verbaux, III, 305.Google Scholar

²⁰ See n. 15 above. Lists of Poisson's publications are given in Royal Society of London, Catalogue of Scientific Papers (1800–1863) (London, 1867–1872), IV, 964–969Google Scholar; in Arago, , op. cit. (n. 8), pp. 672–689Google Scholar; and in Métivier, et al. , op. cit. (n. 7), pp. 212–225.Google Scholar The last of these supersedes the other two. Poisson's experience with the Savans étrangers was by no means unusual. He was more fortunate than some in having such ready access to alternative journals in which his work could be published.

²¹ See n.1 above.

²² Procès-verbaux, III, 563, 594–597.Google Scholar

²³ Ibid., III, 532, 623, 626. Though it was certainly within the Academy's rules not to proceed at once to an election (cf. Réglement intérieur de la Classe des Sciences Mathématiques et Physiques de l'Institut National [Paris, an XI], p. 7), one nevertheless wonders at the legality of the academicians' refraining for so long from filling a vacancy in their midst. Perhaps the Academy's officers also had doubts on the matter, for on both occasions the unanimity of the decision was carefully recorded.

²⁴ Clairaut, A., Théorie de la figure de la terre (2nd ed., Paris, 1808)Google Scholar. Cf. Procès-verbaux, IV, 45.Google Scholar Poisson's contribution to the new edition amounted to no more than a short preface and the elimination of typographical errors from the first edition.

²⁵ Procès-verbaux, IV, 78, 89–92Google Scholar; cf. Poisson, , ‘Sur les inégalités séculaires des moyens mouvements des planètes’, J. École Polytechnique, 8 (1809), 1–56.Google Scholar

²⁶ Procès-verbaux, IV, 181, 190–192Google Scholar; cf. Poisson, , ‘Sur le mouvement de rotation de la terre’, J. École Polytechnique, 8 (1809), 198–218.Google Scholar

²⁷ Procès-verbaux, IV, 266, 290–291Google Scholar; cf. Poisson, , ‘Sur la variation des constantes arbitraires dans les questions de mécanique’, J. École Polytechnique, 8 (1809), 266–344.Google Scholar

²⁸ Procès-verbaux, IV, 405.Google Scholar This prize had been endowed by Lalande towards the end of his life, to be awarded each year for ‘the most curious observation or the most useful memoir for the progress of astronomy’ during the previous twelve months (resident members of the Institut being ineligible for the award).

²⁹ Ibid., IV, 253.

³⁰ Gratten-Guinness had laid considerable stress on the disputes that later erupted between Biot and Arago (op. cit., n. 5). He sees the first signs of these in a misunderstanding that Arago described many years later over their 1806 joint paper on atmospheric refraction, (Arago, , Oeuvres complètes, XI (Paris, 1859), 702–703)Google Scholar. However, either any tension aroused at that stage must soon have dissipated, or else Arago succeeded very well in bottling up his resentment, because during and after the Spanish expedition the two men seem to have worked together in close and friendly co-operation.

³¹ Crosland has suggested that Lalande's place was not filled for so long because it had been earmarked for the absent Arago from the start (Crosland, , Society of Arcueil, pp. 163–165)Google Scholar. An indication that Arago's claim to the position was not as clear-cut as that is provided by the terms in which the Academy decided to award the 1808 Lalande Prize to his rival, Mathieu. To be sure, the report adopted by the Academy leaves no doubt that Arago's merits were regarded as superior to Mathieu's; but it also reveals that his work was not seen as sufficiently outstanding to prevent Mathieu's nevertheless being given the prize. ‘In the absence of new observations and important works’, we read, it had been decided to award the prize ‘as encouragement to M. Mathieu for the work to which he has devoted himself in conjunction with M Biot, to determine the length of the pendulum. The Commission points out that it would have proposed giving the award to M. Arago, had it not judged him sufficiently encouraged by his nomination to the place of adjoint at the Bureau des Longitudes’ (Procès-verbaux, IV, 149).Google Scholar

³² Lefort, F., ‘Un savant chrétien: J.-B. Biot’, Le Correspondant, 72 (1867), 955–995; p. 965.Google Scholar Though Lagrange may have paid lip service to Biot's argument, it does not automatically follow that he cast his vote for Arago in what was, after all, a secret ballot.

³³ Arago, , History of My Youth, p. 106.Google Scholar

³⁴ Bucciarelli, Louis L. and Dworsky, Nancy (Sophie Germain: An Essay in the History of the Theory of Elasticity [Dordrecht, 1980], p. 130)CrossRefGoogle Scholar offer as their guess, though without giving any reasons for their choice, that Poisson's four votes might have come from Laplace, Berthollet, Biot and Gay-Lussac. This, however, is to neglect both Lefort's claim that Biot was an active campaigner on Arago's behalf and the manifold evidence available of Poisson's strong links with other members of the geometry section besides Laplace, most notably with Lagrange and Lacroix. If we accept Lefort's statement that, in addition to Biot, two other mathematician members of the Academy, Delambre and Legendre, were Arago supporters, we are left with Laplace, Lagrange, Lacroix and the 79-year-old Bossut as the four members of the First Class most likely to have cast their votes for Poisson on this occasion.

³⁵ Index biographique de l'Academie des Sciences du 22 décembre 1666 au 1^et octobre 1978 (Paris, 1979).Google Scholar

³⁶ The other members of the section at this time were then well known balloonist and public lecturer in experimental physics J.-A.-C. Charles, the navigator turned expert on optical instruments A.-M. Rochon, the professor of experimental physics at the Collège de France, Louis Lefévre-Gineau, and the hydrographer and one-time balloonist Pierre Levêque.

³⁷ Frankel, Eugene, ‘Corpuscular Optics and the Wave Theory of Light: The Science and Politics of a Revolution in Physics’, Social Studies of Science, 6 (1976), 141–184CrossRefGoogle Scholar; Chappert, André, Étienne-Louis Malus (1775–1812) et la théorie corpusculaire de la lumière (Paris, 1977).Google Scholar

³⁸ Bucciarelli, and Dworsky, (op. cit. [n. 34], pp. 35–38)Google Scholar suggest that Laplace was scheming to have Poisson elected to the ‘general physics’ section as early as the first part of 1809, that is, several months before Arago captured the vacant astronomy position. This is, at least, their suggested explanation for the Academy's announcement in April of that year of a special prize competition on the mathematical theory of the vibrations of elastic solids which they interpret as ‘part of Laplace's efforts to be helpful to Poisson and to turn his attention to terrestrial problems of physics that were of interest to Laplace himself’. Three points, however, tell against this suggestion. First, Poisson was hard at work at precisely this time on the final two parts of his trilogy of papers on problems in celestial mechanics, and we have Libri's testimony concerning Poisson's work habits that he always confined his attention exclusively to one question at a time (Libri, , op. cit., [n.8], p. 432)Google Scholar. Since his chances of election to the Academy must at that point have seemed much brighter in astronomy than in physics, it appears unlikely that he would have diverted his attention at this stage to the physics-oriented topic of the prize competition. Secondly, Laplace already had a favoured candidate, Malus, for the next opening in the physics section. Any plans he might have had for Poisson in this connection must, therefore, have been very long-range indeed. Finally, as Bucciarelli and Dworsky themselves admit, there is no evidence that Poisson took up the question posed by the prize competition until several years after this. If he did take it up once his celestial mechanics memoirs were completed, the work appears to have come to nothing at that time.

³⁹ Among Ampère's papers at the Archives de l'Académie des Sciences, Paris (box 26, chemise 392) is a voluminous MS headed ‘Cours de Mécanique fait par M^r. Poisson en 1812. 1^er Division. École Royale Polytechnique’ and signed at the end ‘Le 20 fevrier 1816 pour copie conforme a mes régistres. Le Brun’, which includes frequent cross-references to Poisson's Traité. Grattan-Guinness has recently pointed out that the Traité is in fact a re-working of a 500-page set of lecture notes published in 1810 under the title Cours de mécanique (Grattan-Guinness, , Ann. Sci., 38 [1981], 663–690; p. 690).Google Scholar

⁴⁰ Procès-verbaux, IV, 560, 562–3.Google Scholar The announcement of this competition has seldom been noted by historians, presumably chiefly because the prize was never awarded. The full text of the competition topic is given in Archives de l'Académic des Sciences, Paris, packet for the séance of 6 January 1812, as follows: Déterminer par le calcul, et confirmer par l'expérience, la manière dont l' électricité se distribue à la surface des corps électriques, et considérés soit isolément, soil en présence les uns des autres, par example, à la surface de deux sphères électrisées, et en présence l'une de l'autre. Pour simplifier le problème, la Classe ne demande que l'examen des cas oú l'électricité répandue sur chaque surface reste toujours de la méme nature. The renewal of the competition on elastic plate vibrations was announced at the same meeting.

⁴¹ The published version of the competition topic was, in the detail it provided, even more closely aligned with the direction that Poisson's work was taking than that approved initially, which had merely specified a prize for research on ‘the laws of electrical equilibrium of two spheres in the presence of each other’. (Procès-verbaux, IV, 562–3).Google Scholar

⁴² On Trouville, , cf. ‘Extraite d'un memoire sur la manière d'employer le syphon pour éleven l'eau dans le machine du C. Trouville, par le C. Prony’, Bull. Soc. Philomathique, 2, 92–94Google Scholar (in No. 36, Ventose, an VIII). However, this gives no details at all about Trouville himself.

⁴³ For the events surrounding the election, see Procès-verbaux, V. 20–40.Google Scholar Bertrand provides some additional colourful details about the lobbying that took place beforehand (Revue des deux mondes, 137, 1896, 287–288)Google Scholar. (I owe this and several other references to Jim Hofmann). Costabel (op. cit. [n. 17]) notes that Poisson's election was confirmed by Napoleon within three weeks. He sees this promptness as a sign that ‘the authorities had not forgotten the acquiescent attitude that [Poisson] had adopted in 1804’ in heading off a rebellion among the students at the École Polytechnique against the proclamation of the Empire. However, a delay of only three weeks was by no means exceptional in this regard; on the contrary, this was about the average time it took for approval to be granted.

⁴⁴ In the published version, the first two of Poisson's presentations were combined into a single paper, and in the absence of the original manuscripts it is impossible to determine how much of the work Poisson had actually completed at the time of the election. Further to confuse the issue, the date on which the first part was read is wrongly given as 9 May 1812 rather than 9 March, not only in the ‘official’ publication in the Academy's Mémoires but also in the various summaries that were published earlier. This was no typographical error, therefore, but a deliberate attempt to mislead, probably perpetrated in order to lend an air of legitimacy to the publication in the Mémoires of a paper, part of which, having been communicated by someone who was not at the time a member of the Academy, should by rights have appeared in the Savans étrangers instead.

⁴⁵ Poisson was later criticized by some of his colleagues in the Academy for presenting a paper on vibrating elastic surfaces while the long-running Academy competition on that subject was still current (Bucciarelli, and Dworsky, , op. cit. [n.34], p. 65)Google Scholar. In the present case, however, no similar criticism was offered, and there can surely have been no question of impropriety about his actions, the contest having so manifestly been set for his benefit in the first place.

⁴⁶ The two once-sealed notes, together with Gardini's essay, are preserved in the packet of papers dealing with this competition at the Archives de l'Académie des Sciences, Paris.

⁴⁷ Procès-verbaux, V, 250, 292.Google Scholar

⁴⁸ The Academy's electoral procedures are described and their significance in maintaining disciplinary boundaries noted by Crosland, ‘The French Academy of Sciences in the Nineteenth Century’, Minerva, 16, 1978, 73–102.Google Scholar

⁴⁹ On Beccaria, , see my paper, ‘Franklin's Electrical Atmospheres’, British Journal for the History of Science, 6, 1972, 131–151Google Scholar, and Heilbron, J. L., Electricity in the 17th and18th Centuries: A Study of Early Modern Physics (Berkeley, 1979), pp. 362–372.Google Scholar

⁵⁰ Coulomb, , Hist, de l'Acad., 1785 (publ. 1788), Mém. pp. 578–611.Google Scholar

⁵¹ On Aepinus, see Aepinus's Essay on the Theory of Electricity and Magnetism, introductory monograph and notes by R. W. Home, translation by Connor, P. J. (Princeton, 1979).Google Scholar

⁵² Biot, , ‘Sur un probléme de physique, relatif a l'électricité’, Bull. Soc. Philomathique, 3, 21–23Google Scholar (in No 51, Prairial, an IX).

⁵³ Quod summa electricitatum absolutarum quaecumque quam habeant duo corpora, ista dum in contactum veniunt, ct quoquomodo inter se communicant, distribuitur ipsa summa in ipsis juxta rationem capacitatis eorum’.

⁵⁴ Cavendish, , Phil. Trans., 61 (1771), 584–677.CrossRefGoogle Scholar

⁵⁵ Procès-verbaux, IV, 560, 562–3.Google Scholar