¹ The following examples are illustrative. Heat theory is ignored in a discussion of Lavoisier's chemistry in Wolf, A., A History of Science, Technology & Philosophy in the 18th Century (2nd edn., 2 vols., New York: Harper, 1961), i. 366–75.Google Scholar It is all but ignored in this connexion in Hall, A. R., The Scientific Revolution, 1500–1800 (Boston: Beacon, 1956), pp. 328, 336–67.Google Scholar As an example of Lavoisier's conservatism, see Butterfield, H., The Origins of Modem Science, 1300–1800 (new edn., New York: Macmillan, 1960), p. 207.Google Scholar Certainly not all historians have ignored the chemical role of caloric; see Partington, J. R., A History of Chemistry (4 vols., London: Macmillan, 1961–1970), iii. 421–2.Google Scholar

² ‘Expérience sur le passage de l'eau en glace communiquée à l'Académie des Sciences’, Introduction aux Observations sur la Physique, ii (1772), 510–11.Google Scholar

³ The report was made in August 1772 and subsequently published: ‘Expériences du docteur Black sur la march de la chaleur dans certaines circonstances’, Introduction aux Observations sur la Physique, ii (1772), 428–31.Google Scholar For the report on Black to the Academy see Guerlac, H., Lavoisier—The Crucial Year: The Background and Origin of his First Experiments on Combustion in 1772 (Ithaca, N.Y.: Cornell Univ. Press, 1961), pp. 68–9, 92–3.Google Scholar

⁴ This is the manuscript of July 1772 discussed below. Concerning its identity with that to which Lavoisier referred, see Guerlac, , op. cit. (3), pp. 93–7.Google Scholar

⁵ Lavoisier used various terms to indicate heat matter. In manuscripts of 1773 and in his Opuscules he referred to this fluid as phlogiston or an inflammable principle; see Fric, René, ‘Contribution à l'étude de l'évolution des idées de Lavoisier sur la nature de l'air et sur la calcination des métaux’, Arch. Int. Hist. Sci., xii (1959), 149–50Google Scholar, and Opuscules Physiques et Chymiques (Paris, 1774), pp. 279–80.Google Scholar However, Lavoisier's later denial of the existence of phlogiston resulted in his subsequent use of different terminology. Except for this restriction, prior to the nomenclature revision of 1787 (Guyton de Morveau, L. B. et al. , Méthode de Nomenclature Chimique proposée par MM. de Morveau, Lavoisier, Bertholet, & de Fourcroy [Paris, 1787]Google Scholar, cited hereafter as Nomenclature Chimique), Lavoisier was indifferent to the terminology he used. He called heat the igneous fluid, fire matter, heat matter, the principle of heat, the matter of fire or light, the matter of fire, heat, and light, in addition to other similar phrases. In the manuscript preparation of his Traité de Chimie he proposed the terms ‘thermogéne’ and ‘principe échauffant’ (quoted in Daumas, M., ‘L'élaboration du Traité de Chimie de Lavoisier’, Arch. Int. Hist. Sci., iii [1950], 580, 584)Google Scholar, although in the published Traité he used ‘calorique’, conforming to the new nomenclature (Nomenclature Chimique, p. 30).Google Scholar The term ‘calorique’ was probably Guyton's invention. The adjective ‘calorifique’ had seen widespread usage throughout the century. However, in 1785 Guyton had used it as a noun indicating the matter of heat or of fire; see Partington, , op. cit. (1), iii. 421.Google Scholar Cf. the same usage in Observations sur la Physique, xxx (1787), 45–6Google Scholar, and see Fox, R., The Caloric Theory of Gases from Lavoisier to Regnault (Oxford: Clarendon Press, 1971)Google Scholar, p. 6n. Another change in the new nomenclature was the listing of light as a distinct element; see Nomenclature Chimique, pp. 28–30.Google Scholar Lavoisier was indifferent to the problems of differentiating between heat and light and of specifying the chemical role of light: see, for example, ibid., p. 293n., and Traité Élémentaire de Chimie (2 vols., Paris, 1789), i. 200–2Google Scholar; also Metzger, H., ‘Newton: La théorie de l'émission de la lumière et la doctrine chimique au XVIIIème siècle’, Archeion, xi (1929), 24–5.Google Scholar He did state in a few places that the state of oxygen gas is due to both caloric and light combined in it: for example, in Nomenclature Chimique, p. 296Google Scholar; Traité, i. 201; ii. 523Google Scholar; and Mémoires de Chimie (2 vols., Paris, 1803?), ii. 155.Google Scholar In the Traité de Chimie, ii. 523Google Scholar, he gave as a basis for this some work by Berthollet showing that ‘obscure’ heat cannot produce oxygen gas from oxide of mercury.

⁶ Opuscules, p. 280.Google Scholar

⁷ Gough, J- B., ‘Lavoisier's early career in science: an examination of some new evidence’, Br. J. Hist. Sci., iv (1968–1969), 52–7.CrossRefGoogle Scholar

⁸ Quoted in ibid., 54.

⁹ For the probable date of composition, see Guerlac, , op. cit. (3), pp. 100–1.Google Scholar The manuscript, originally published by Fric, in op. cit. (5), is reproduced in Guerlac, , pp. 215–23.Google Scholar

¹⁰ Quoted in Fric. op. cit. (5), 145.Google Scholar The words in brackets are those crossed out in the manuscript.

¹¹ Dissolution was considered to be a chemical process; see Venel, G. F., ‘Menstrue & action menstruelle, ou dissolvant & dissolution’, Encyclopédie ou Dictionnaire Raisonné …, ed. Diderot and d'Alembert, x (1765), 339, 340.Google Scholar As far as I can tell, however, prior to Lavoisier, of all changes of state only evaporation (not vaporization in general) was considered to be a dissolution in which air (not fire) acts as the menstruum; see [Turgot, A. R. J.], ‘Expansibilité’, Encyclopédie, vi (1756), 282Google Scholar, and the corrections, p. 927.

¹² Cooling was the single phenomenon which indicated to Lavoisier a combination of fire had taken place; the only fusion phenomenon which he associated with his theory of combination of fire was the cooling of an ice-salt mixture. See Fric, op. cit. (5), 141–2.Google Scholar

¹³ ibid., 147–51.

¹⁴ Guerlac argues that the appearance of the July memoir as being devoted primarily to explain the fixation of air is because the memoir was never completed; see ‘Lavoisier's draft memoir of July 1772’, Iris, lx (1969), 381–2.Google Scholar Cf. Morris, R. J., ‘Lavoisier on air and fire: the memoir of July 1772’, Isis, Ix (1969), 374–7.CrossRefGoogle Scholar

¹⁵ ‘De l'élasticité et de la formation des fluides élastiques’, published by Gough, J. B., in ‘Nouvelle contribution à l'étude de l'évolution des idées de Lavoisier sur la nature de l'air et sur la calcination des métaux’, Arch. Int. Hist. Sci., xxii (1969), 271–5.Google Scholar

¹⁶ See Daumas, M., Lavoisier, Théoricien et Expérimentateur (Paris: Presses Universitaires de France, 1955), pp. 38–41.Google Scholar

¹⁷ ‘De la combinaison de la matière du feu avec les fluides évaporables, et de la formation des fluides élastiques aëriformes’ [1778], Mémoires de l'Académie Royale des Sciences, 1777 (1780), p. 420.Google Scholar The date in brackets refers to the date the paper was first read. The date in parentheses is the publication date for the volume of Mémoires. Thus this paper, presented to the Academy in September 1777, was read in July 1778 (Daumas, , op. cit. [16], pp. 40, 42)Google Scholar, and published in 1780 in the Mémoires for 1777.Google Scholar

¹⁸ Lavoisier cited Richman, George Wilhelm (1711–1753)Google Scholar, de Mairan, Jean Jacques Dortous (1678–1771)Google Scholar, Cullen, William (1710–1790)Google Scholar, and Bauré, Antoinc (1728–1804)Google Scholar as having demonstrated evaporative cooling (ibid., p. 424, and footnotes). He had cited Cullen and Baumé in the same context in 1775 (Gough, , op. cit. [15], 271Google Scholar; see Gough's discussion).

¹⁹ Mém. Acad. R. Sci. 1777, p. 425.Google Scholar The concept of air as a state had been stated earlier by Turgot (loc. cit. [11]). For a brief discussion of the development of this concept, see Crosland, M. P., ‘The development of the concept of the gaseous state as a third state of matter’, Actes du X^e Congrès International d'Histoire des Sciences; Ithaca, 1962 (1964), pp. 852–53.Google Scholar For the possible influence of Turgot on Lavoisier, see Gough, , op. cit. (15), 269–70.Google Scholar Cf. Morris, , op. cit. (14), 377n.Google Scholar

²⁰ Although a persistent theme since at least 1766, his only published reference to his idea prior to the Mémoires for 1777Google Scholar was the short passage in the Opuscules quoted above. He may have mentioned the idea in May 1777; see Daumas, , op. cit. (16), p. 38.Google Scholar A memoir in the Oeuvres de Lavoisier (6 vols., Paris, 1862–1893; v. 271–81)Google Scholar purports to be a slightly modified version of the one read in May 1777. The original was not published.

²¹ Mém. Acad. R. Sci. 1777, pp. 429–32.Google Scholar

²² ‘Mémoire sur la combustion en général’ [1777], Mém. Acad. R. Sci. 1777, pp. 592–600.Google Scholar The chronological difficulties with this paper are similar to the previous one; see n. 17 above. The paper was read in November 1777 and again in December 1779; see Daumas, , op. cit. (16), pp. 40, 44.Google Scholar Although the first reading preceded that of the memoir on the formation of elastic fluids (see n. 17), it was published in the Mémoires following the latter and was clearly written with the latter in mind.

²³ Mém. Acad. R. Sci. 1777, p. 595.Google Scholar

²⁴ ibid.

²⁵ In the Opuscules (p. 280)Google Scholar he had called the base of air ‘la partie fixe’ but he had used the terminology of the paper on combustion in preceding articles published in the Mémoires for 1777. He referred to the base of aeriform fluids in his ‘Mémoire sur la combustion des chandelles dans l'air atmosphérique et dans l'air éminemment respirable’ (Mém. Acad. R. Sci. 1777, p. 204)Google Scholar, in ‘Expériences sur la combinaison de l'alun avec les matières charbonneuses et sur les altérations qui arrivent à l'air dans lequel on fait brûler du pyrophore’ (Mém. Acad. R. Sci. 1777, p. 371)Google Scholar, and in his ‘Mémoire sur la vitriolisation des pyrites martiales’ (Mém. Acad. R. Sci. 1777, p. 399n.).Google Scholar

²⁶ Mém. Acad. R. Sci. 1777, pp. 595–8.Google Scholar

²⁷ From early spring of 1777 he was assisted in his experimental work by Laplace, and their collaboration is often cited in subsequent papers; see Guerlac, H., ‘Laplace's collaboration with Lavoisier’, Actes du XII^e Congrès International d'Histoire des Sciences; Paris, 1968, iii B., 31–36.Google Scholar In addition to the papers discussed, there are several others which stem from this period and express the same viewpoint. One is the manuscript mentioned in n. 20 above. Two others extend his theory of vapours to show that it is in accord with chemical phenomena of a variety of elastic fluids. The first is ‘De quelques substances qui sont constamment dans l'état de fluides aëriformes au degré de chaleur et de pression habituel de l'atmosphere’. Almost all the experiments cited were performed in February 1776. The paper was submitted to the Academy early in 1776 to be initialled, déposé in 1777 (Daumas, , op. cit. [16], pp. 36–7, 41)Google Scholar, and published in Lavoisier, 's posthumous Mémoires de Chimie, i. 348–85.Google Scholar The second is entitled ‘Mémoire sur quelques fluides qu'on peut obtenir dans l'état aériforme à un degré de chaleur peu supérieur à la temperature moyenne de la terre’ [1780], Mém. Acad. R. Sci. 1780 (1784), pp. 334–43.Google ScholarDaumas, (op. cit. [16], p. 45)Google Scholar describes it as ‘la suite naturelle’ of the preceding paper.

²⁸ Fric, op. cit. (5), 152.Google Scholar The date of this manuscript is uncertain although it must have been written before 1781. Its content suggests a close relation with the memoirs of July 1772 and April 1773.

²⁹ ibid., italics mine. Cf. a similar statement in the paper of July 1772, ibid., 142.

³⁰ Experiments and Observations on Animal Heat and the Inflammation of Combustible Bodies, being an Attempt to Resolve these Phaenomena into a General Law of Nature (London, 1779).Google Scholar He published a considerably expanded second edition in 1788, also in London.

³¹ Crawford acknowledged his indebtedness to these two men. For example, see Animal Heat (1779), pp. 2, 4Google Scholar, 12n., 17n., 49n. Irvine was professor of chemistry at Glasgow; see Kent, Andrew, ‘William Irvine, M.D.’, in An Eighteenth-Century Lectureship in Chemistry, ed. Kent, Andrew (Glasgow: Jackson, 1950), pp. 140–50.Google Scholar Crawford had gone to Scotland in 1776 where he attended Irvine's lectures. His experiments were begun in the summer of 1777 (Animal Heat [1779], p. 18).Google Scholar His theory was communicated to Irvine and others that autumn and explained to the faculty and students in Edinburgh during the 1777–8 session (Animal Heal [1788], p. 4).Google Scholar For a discussion of various aspects of Crawford's ideas ‘see Fox, R., ‘Dalton's caloric theory’, in John Dalton & the Progress of Science, ed. Cardwell, D. S. L. (Manchester: Manchester Univ. Press, 1968), pp. 190–2Google Scholar; Partington, J. R. and McKie, D., ‘Historical studies on the phlogiston theory. III: Light and heat in combustion’, Annals of Science, iii (1938), 346–50Google Scholar; and Mendelsohn, E., Heat and Life: The Development of the Theory of Animal Heat (Cambridge, Mass.: Harvard Univ. Press, 1964), pp. 123–33CrossRefGoogle Scholar, and passim.

³² Crawford, (Animal Heat [1779], p. 16)Google Scholar defined capacity as the power of a given substance to collect and retain ‘the element of fire’, and it is determined by the change of temperature produced in the substance by a given quantity of fire compared to the change produced by the same quantity of fire in the temperature of some other substance (water) taken as a standard. He did not use the term ‘specific heat’. This term was introduced by Magellan; see below.

³³ ibid., p. 51. Crawford was apparently the first person to determine the heat capacities of airs; see McKie, D. and Heathcote, N. H. de V., The Discovery of Specific and Latent Heats (London, 1935), p. 43Google Scholar, n. 4.

³⁴ Animal Heat (1779), p. 58.Google Scholar

³⁵ ibid., p. 61.

³⁶ ibid., p. 76.

³⁷ ibid., p. 15n.

³⁸ ibid., p. 49n.

³⁹ Magellan played a central role in introducing British ideas of pneumatic chemistry into France in 1771–2 (Guerlac, op. cit. [3], chapter II, passim.) and possibly transmitted to Paris the brief article published in 1772 (cited in n. 3) concerning Black's work on heat (ibid., pp. 68–9).

⁴⁰ Magellan, J. H., ‘Essai sur la nouvelle théorie du feu élémentaire et de la chaleur des corps’, in Collection de Différens Traités sur des Instrumens d'Astronomie, Physique, etc. (London, 1780)Google Scholar; ‘Essai sur la nouvelle théorie du feu élémentaire & de la chaleur des corps’, Observations sur la Physique, xvii (1781), 375–86; and ‘;Suite du mémoire de M. H. Magellan sur le feu élémentaire et la chaleur: Sommaire de l'ouvrage du docteur Crawford’, Observations sur la Physique, xvii (1781), 411–22. An announcement of the publication of Crawford's book and a brief summary of his theory appeared early in 1780; see ‘Extrait d'une lettre de M. Magellan de la Société Royale de Londres sur les montres nouvelles qui n'ont pas besoin d'être montées, sur celles de M. Mudge, & sur l'ouvrage de M. Crawford’, Observations sur la Physique, xvi (1780), 62–3.Google Scholar For a summary of Magellan's account see McKie, and Heathcote, , op. cit. (33), pp. 40–5.Google Scholar

⁴¹ Observations sur la Physique, xvii (1781), 375.Google Scholar

⁴² Observations sur la Physique, xvii (1781), 376.Google Scholar Its appearance in the 1780 edition of Magellan's paper (op. cit. [40], 167) is apparently the first published use of this term; see McKie, and Heathcote, , op. cit. (33), p. 42.Google Scholar

⁴³ Observations sur la Physique, xvii (1781), 381.Google Scholar

⁴⁴ ibid., 384. This is apparently the first published table of specific heats; see McKie, and Heathcote, , op. cit. (33), p. 43.Google Scholar

⁴⁵ Deluc, J. A., ‘To the conductors of the Edinburgh Review’, The Edinburgh Review, vi (1805), 511.Google Scholar In fact, Deluc stated that the Academy gave Monge and Vandermonde ‘the special commission to examine and follow that new view [Crawford's].’

⁴⁶ Daumas, , op. cit. (16), p. 45.Google Scholar The vaporization was produced by heated mercury and the temperature change of the latter was measured.

⁴⁷ ibid., p. 46.

⁴⁸ ibid., p. 47. The ‘seconde séance’ of experiments with the calorimeter is dated 27 July; the ‘première séance’ is mentioned but not dated.

⁴⁹ ibid., p. 48; Lavoisier, and Laplace, , ‘Mémoire sur la chaleur’ [1783], Mém. Acad. R. Sci. 1780 (1784), pp. 355–408.Google Scholar Discussions of this paper are common in secondary literature; for example see Wolf, op. cit. (1), i. 183–8.Google Scholar

⁵⁰ Lavoisier, and Laplace, , op. cit. (49), p. 388.Google Scholar The term latent heat was not used. Magellan had rejected the term on the grounds that, strictly speaking, the effects of heat in this form are sensible not latent (Observations sur la Physique, xvii [1781], 381; cf. 385).Google Scholar

⁵¹ ibid., pp. 356, 383–4, 394. In addition to the terminology and explicit references to Crawford and his theory, the citation of Kirwan (‘Kirven’, pp. 385, 387, 390)Google Scholar is further indication of Magellan as their source of information.

⁵² ibid., pp. 385–9. The calculations of absolute zero are further indications that Lavoisier and Laplace had read Magellan's articles. Although the calculational technique can be derived from Crawford's discussion and although, judging from William Irvine's posthumously published Essays (McKie, and Heathcote, , op. cit. [33], pp. 130–4)Google Scholar, Crawford might well have learned the method during his stay in Glasgow, he made no mention of it and only referred in passing to the ‘point of total privation’ of heat (Animal Heat, p. 97n.). Magellan, on the other hand, discussed the theory and as an example calculated the total quantity of heat in ice at its melting point; see Observations sur la Physique, xvii (1781), 383–4.Google Scholar He stated further that he had obtained the method from Kirwan (ibid., 384). For a discussion of the technique of calculation, see McKie, and Heathcote, , op. cit., pp. 130–7.Google Scholar

⁵³ Mém. Acad. R. Sci. 1780, p. 394.Google Scholar Although they described a method to determine the specific heat of airs (pp. 295–6), none were given. Such work was carried out during the winter of 1783–4 but not published until the Mémoires de Chimie.

⁵⁴ Mém. Acad. R. Sci. 1780, p. 406.Google Scholar The authors cited no experimental data to support this explanation; see Mendelsohn, , op. cit. (31), pp. 150–1.Google Scholar

⁵⁵ Mém. Acad. R. Sci. 1780, p. 387.Google Scholar

⁵⁶ Daumas, , op. cit. (16), pp. 45, 46.Google Scholar The account of this work was published in Lavoisier, 's Mémoires de Chimie, i. 246–80, 295–311.Google Scholar

⁵⁷ Mém. Acad. R. Sci. 1780, p. 374.Google Scholar

⁵⁸ ibid., pp. 391–2. Lavoisier and Laplace continued their experiments with the ice-calorimeter during the late autumn and winter of 1783–4 (Daumas, , op. cit. [16], p. 51)Google Scholar, but the results were published much later in the Mémoires de Chimie, i. 121–47.Google Scholar

⁵⁹ Mémoire sur l'affinité du principe oxygine avec les différentes substances auxquelles il est susceptible de s'unir’ [1785], Mém. Acad. R. Sci. 1782 (1785), pp. 530–40.Google Scholar It was presented in December 1783 and read in 1785; see Daumas, , op. cit. (16), pp. 51, 56.Google Scholar

⁶⁰ ibid., pp. 531–2. The forces of affinity and atmospheric pressure are opposed by that of heat matter, and the solid, liquid, and aeriform states depend upon whether the latter is weaker, equal to, or stronger than the former.

⁶¹ ibid., pp. 534–5.

⁶² For a general discussion of Lavoisier's ideas on affinity see Daumas, M., ‘Les conceptions de Lavoisier sur les affinités chimique et la constitution de la matière’, Thalès, vi (1949–1950), 69–80.Google Scholar Daumas virtually ignores the role of caloric in this context.

⁶³ ‘Réflexions sur le phlogistique pour servir de développement à la théorie de la combustion & de la calcination publiée en 1777’ [1785], Mém. Acad. R. Sci. 1783 (1786), pp. 505–38Google Scholar; Daumas, , op. cit. (16), p. 58.Google Scholar

⁶⁴ Mém. Acad. R. Sci. 1783, p. 505.Google Scholar

⁶⁵ ibid., pp. 509, 517; see below for Lavoisier's ideas on the weight of heat fluid.

⁶⁶ ibid., p. 506; cf. ‘Sur la combustion’ [1777], Mém. Acad. R. Sci. 1777, pp. 595–6Google Scholar for a similar argument (see above).

⁶⁷ Mém. Acad. R. Sci. 1783, pp. 509–10.Google Scholar

⁶⁸ ibid., p. 519. Wilcke, Johan Karl (1732–1796).Google Scholar Wilcke's work on specific heat was published in the memoirs of the Swedish Academy for 1781; see McKie, and Heathcote, , op. cit. (33), pp. 95–108.Google Scholar Lavoisier and Laplace had referred to this paper in the joint memoir stating they had seen it after reading their own in June 1783 (Mém. Acad. R. Sci. 1780, p. 373n.).Google Scholar Wilcke mentioned Black, Crawford, and Kirwan, deriving his information from Magellan (McKie, and Heathcote, , op. cit., p. 108).Google Scholar

⁶⁹ The Traité de Chimie (i. 1–3)Google Scholar opens with a similar statement which is repeated in the Mémoires de Chimie (i. 3–4).Google Scholar

⁷⁰ Mém. Acad. R. Sci. 1783, p. 524.Google Scholar In his Mémoires de Chimie (i. 5) he identified the force as universal gravitation.

⁷¹ Indeed, heat capacity was the term most generally used.

⁷² Mém. Acad. R. Sci. 1783, pp. 527–8.

⁷³ ibid., pp. 529–30.

⁷⁴ ibid., pp. 532–3.

⁷⁵ This was mentioned in the joint memoir on heat (Mém. Acad. R. Sci. 1780, p. 401)Google Scholar and repeated in his ‘Mémoire sur la formation de l'acide nommé air fixe ou acide crayeux’, Mém. Acad. R. Sci. 1781, p. 454Google Scholar, where he stated that the change in volume is proportional to the change in density. According to modern theory, the volume should not change.

⁷⁶ Mém. Acad. R. Sci. 1783, pp. 530–2.Google Scholar His knowledge of the relative specific heats of the two airs probably came from Crawford. Apparently Lavoisier and Laplace only determined the specific heats of vital and atmospheric air (see n. 83).

⁷⁷ ibid., pp. 535–6.

⁷⁸ ibid., p. 536. Lavoisier added (p. 537) that the ideas relating absorption and release of heat to volumetric changes ‘ne me sont point propres. Mrs. Vandermonde & Monge ont avancé la même chose dans un Mémoire lü à l'Académie.’ I have not been able to locate this paper. Lavoisier stated that Monge, among others, considered all mixtures and combinations in which there is a release of the matter of heat as species of combustion, and the example given was the mixing of water with various substances causing a reduction in volume accompanied by a release of heat. Lavoisier again referred to the ideas of Monge and Vandermonde in his Mémoires de Chimie (i. 8).Google Scholar In discussing his idea that the capacity of a substance to contain heat fluid depends upon the internal pore-space within the substance, Lavoisier stated that the consequence ‘qui se trouve confirmée par les expériences de MM. Wilk [sic], Vandermonde, Monge, de la Place, et par les miennes, ne me paroit pas moins exacte; c'est que si on rapproche, par une force égale quelconque, les molécules de plusieurs corps, la quantité de calorique qui en sortira, sera différente.’ An incomplete manuscript by Monge describing a theory of heat has been published by Taton, R., ‘A propos de l'oeuvre de Monge en physique’, Rev. Hist. Sci., iii (1950), 177–9.Google Scholar It was purportedly written around 1783 (ibid., 177) although use of the term ‘calorique’ suggests a later date. It expresses the same ideas and uses the same terminology as the first part of a 1790 paper published in the second volume (1816) of the Dictionnaire de Physique [Encyclopédie Méthodique] (4 vols., Paris, 1793–1822), pp. 170–1Google Scholar; discussed in Taton, R., L'Oeuvre Scientifique de Monge (Paris: Presses Universitaires de France, 1951), pp. 323–5.Google Scholar In it Monge explained heat phenomena entirely in terms of forces: the mutual attraction among the particles of a substance, the attraction between these particles and caloric, and external pressure. Any change in the first of these which causes the particles of a substance to come closer together will result in the extrusion of some of the interposed caloric (Dictionnaire, ii. 171–2).Google Scholar The origin of these ideas is not known; see n. 45 above, for Monge's possible knowledge of Crawford's theory.

⁷⁹ Mém. Acad. R. Sci. 1783, pp. 537–8.Google Scholar In 1773 in Rozier's journal, he had published an account of temperature changes accompanying the crystallization and solution of salts (‘Observations lues par M. Lavoisier à l'Académie Royale des Sciences sur quelques circonstances de la crystallisation des sels’, Observations sur la Physique, i [1773], 10–13)Google Scholar probably based on experiments performed late in 1771 (Daumas, , op. cit. [16], p. 27).Google Scholar There is no indication in this article nor in his reference to the phenomena in the manuscript memoir of July 1772 (Fric, op. cit. [5], 141–2)Google Scholar that he considered the solution of salt to be simply a change of state like fusion.

⁸⁰ Mém. Acad. R. Sci. 1783, pp. 527, 528.Google Scholar

⁸¹ ibid., p. 536.

⁸² See the discussion above.

⁸³ Although not published until the Mémoires de Chimie (i. 136–7)Google Scholar, in February 1784 (Daumas, , op. cit. [16], p. 51)Google Scholar a value of 0.65 was determined for the specific heat of vital air, a figure considerably less than the value Crawford had given and which Lavoisier had tentatively accepted in 1783.

⁸⁴ Mém. Acad. R. Sci. 1783, p. 535Google Scholar; note that the heat in vital air is free heat (specific heat) and combined heat.

⁸⁵ Traité, i. 57.Google Scholar The discussion of heat is unchanged in the second edition (2 vols., Paris, 1793) and in the third (2 vols., Paris, an IX [1801]).

⁸⁶ Mém. Acad. R. Sci. 1783, pp. 524–5.Google Scholar This can be deduced from the role of air pressure discussed in the 1778 paper on the formation of elastic fluids (Mém. Acad. R. Sci. 1777, pp. 425, 429).Google Scholar

⁸⁷ Traité, i. 8Google Scholar; cf. the somewhat stronger statement in the Mémoires de Chimie (i. 296–7)Google Scholar: ‘Il ne faut point perdre de vue que l'état de liquide n'est, en quelque façon, qu'un état précaire qui est soumis à toutes les variations de pesanteur de l'atmosphère, et qui n'existeroit pas sans cette pesanteur.’

⁸⁸ Traité, ii. 534.Google Scholar Cf. the statement by Guyton de Morveau: ‘Le feu est exactement aux métaux ce que l'eau est aux sels; la fusion est une dissolution; le refroidissement n'est autre chose qu'une évaporation d'une portion de la matière ignée’ (‘Lettre de M. de Morveau à l'auteur de ce recueil sur les crystallisations métalliques’, Observations sur la Physique, xiii [1779], 90). Lavoisier consistently referred to the action of the matter of fire as a dissolution process; and it is clear that he considered dissolution in caloric and combination with caloric to be equivalent (for example, see Mémoires it Chimie, i. 322). The novelty of the concept of fire as a dissolvent is suggested by the debate during the 1770s over whether crystals formed upon the solidification of molten metals are true crystals or whether that true crystals come only from aqueous solutions; Smith, C. S., ‘The development of ideas on the structure of metals’, Critical Problems in the History of Science, ed. Clagett, M. (Madison: Univ. of Wisconsin Press, 1959), p. 488.Google Scholar

⁸⁹ Traité ii. 422–8, 432–3, 437–9.Google Scholar

⁹⁰ Mém. Acad. R. Sci. 1780, pp. 399–400.Google Scholar

⁹¹ In 1787 he had indicated that the combustion of inflammable gas evolves more heat than the combustion of phosphorus (Nomenclature Chimique, pp. 294–7).Google Scholar

⁹² Traité i. 103–15.Google Scholar Similar calculations are given in the joint memoir on heat; however, their purpose was to give a quantitative demonstration of the general principle that when the product of combustion is a solid, more heat is released than when the product is a gas (Mém. Acad. R. Sci. 1780, pp. 398–9).Google Scholar Lavoisier returned to this subject in his Memoires de Chimie (i. 137–41)Google Scholar where he repeated many of his earlier computations. In discussing the presence of caloric combined in solids, he admitted that oxygen in uniting even with phosphorus may not give up all its caloric; hence caloric is probably combined in phosphoric acid and perhaps even in carbon.

⁹³ Madame Lavoisier, in the brief introduction, said that work on this was begun in 1792 (i. p. iii). In one of the memoirs Lavoisier stated that he was writing in 1793 (i. 122). Although the date of publication is usually given as 1805, Partington has shown that the book was distributed in or before 1803 (op. cit. [1], iii. 372). For a discussion of the facts of publication and a résumé of the articles, see Duveen, D. I. and Klickstein, H. S., A Bibliography of the Works of Antoine Laurent Lavoisier, 1743–1794 (London: Dawson, 1954), pp. 199–214Google Scholar, and Duveen, D. I., Supplement to a Bibliography of the Works of Antoine Laurent Lavoisier, 1743–1794 (London: Dawson, 1965), pp. 113–14.Google Scholar W. A. Smeaton in his review of the Duveen and Klickstein Bibliography argues that Lavoisier intended the title to be Mémoires de Physique et de Chimie; see The Library, xi (1956), 133.Google Scholar

⁹⁴ Mémoires de Chimie, i. p. iii.Google Scholar

⁹⁵ The volume (‘Part I’ of the Mémoires) is entitled ‘Vues générales sur le calorique, ou principe de la chaleur, sur ses effets, sur leur mesure, et sur la formation des liquides et des fluides’ (ibid., p. 1). Part I is incomplete, ending on p. 416 in mid-sentence. However, considering the length of the volume and the development of ideas, it is likely that the missing part is comparatively insignificant. The second volume (‘Part II’ of the Mémoires) is entitled ‘De la décomposition de l'air de l'atmosphère …’ (ibid., ii. 1). The purpose of the first few papers is the same as Chapter III of the Traité to demonstrate that atmospheric air is not a simple substance but a mixture. Indeed, the opening sentences of the first paper in Part II indicates the purpose of Part I. ‘Je n'ai présenté jusqu'ici [that is, in Part I] que des considérations générales sur la formation des fluides élastiques aëriformes; j'ai cherché à établir qu'ils sont tous formés de la solution d'une substance quelconque, dans le calorique et la lumiére. Il est résulté des principes que j'ai posés, que notre atmosphère devoit être un mélange, un composé de toutes les substances susceptibles d'être tenues dans l'état aëriforme aux degrés de chaleur et de pression que nous éprouvons’ (ibid., ii. 1–2).

⁹⁶ The increased length is due to the inclusion of four papers by an associate Armand Seguin (which comprise over a fourth of the entire volume) and of papers by Lavoisier, the contents of most of which had been only summarized or alluded to in his earlier works.

⁹⁷ Mém. Acad. R. Sci. 1783, p. 526Google Scholar; Mém. Acad. R. Sci. 1780, pp. 399–400.Google Scholar

⁹⁸ A major part of the manuscript of 1775 is devoted to a discussion of the different degrees of affinity that fire has for substances with which it is combined in forming the vaporous state; see Gough, , op. cit. (15), 272–5.Google Scholar

⁹⁹ In the 1785 essay on phlogiston, he had indicated that, strictly speaking, heat can never be absolutely free because of the mutual adherence between it and the particles of other substances (Mém. Acad. R. Sci. 1783, pp. 526–7).Google Scholar

¹⁰⁰ Mémoires de Chimie, i. 14.Google Scholar

¹⁰¹ ibid., i. 137.

¹⁰² ibid., i. 286–8.

¹⁰³ The same inconsistency occurs in Lavoisier's use of the term ‘dissolution’. The dissolution of metals in acids is different from the dissolution of salts in water. In the former, the elementary constituents of both metal and acid are affected, whereas in the latter the individual particles of the salt are separated without affecting their original identity. In the Traité de Chimie (ii. 423–4)Google Scholar, Lavoisier attempted to distinguish these two kinds of reactions by restricting the term ‘dissolution’ to apply to the former and using the term ‘solution’ for the latter. Unfortunately this distinction was not rigidly maintained either in the Traité or in his other works. Robert Kerr in his translation was more precise in his use of the terminology than was Lavoisier in the original: Elements of Chemistry in a New Systematic Order Containing All the Modern Discoveries (Edinburgh, 1790).Google Scholar Compare Kerr's translation (pp. 368–72, 375, 380) with the corresponding sections in the Traité (ii. 423–8, 432, 438).Google Scholar

¹⁰⁴ Traité ii. 422–3.Google Scholar

¹⁰⁵ Duveen, and Klickstein, , op. cit. (93), p. 201Google Scholar, describe it as a ‘monograph on physics’.

¹⁰⁶ Mémoires de Chimie, i. 246–80, 295–311.Google Scholar

¹⁰⁷ Mém. Acad. R. Sci. 1780, p. 374.Google Scholar In the opening paragraph of the memoir on the expansion of liquids, Lavoisier stated ‘il sembleroit done qu'il existe une sorte de relation entre l'augmentation de capacité de chaleur qui a lieu dans les changemens d'état, et l'augmentation de dilatabilité’ (Mémoires de Chimie, i. 295).Google Scholar

¹⁰⁸ Mém. Acad. R. Sci. 1780, p. 391.Google Scholar

¹⁰⁹ Mémoires de Chimie, i. 281. Seguin denied there is a direct relationship between heat capacity and expansion (Annales de Chimie, iii [1789], 154n.)Google Scholar and in 1790 claimed that he had discussed the matter several times with Lavoisier and had persuaded him to abandon the view that there is a correlation between the two effects; see ‘Résponse de M. Seguin à la lettre de M. de Luc insérée dans le Journal de Physique du mois de mars 1790’, Observations sur la Physique, xxxvi (1790), 420.Google Scholar However, influence of the idea is seen in the opening lines of the paper on the expansion of fluids (n. 107 above).

¹¹⁰ See Morris, , op. cit. (14), 377–9Google Scholar; cf. Guerlac, , op. cit. (14), 380–2.Google Scholar

¹¹¹ Partington, (op. cit. [1], iii. 131)Google Scholar described Lavoisier's concept of air as a state as ‘an extension of Black's theory of latent heat’. See similar statements in McKie's introduction to Lavoisier, 's Elements of Chemistry (op. cit. [103], pp. xxiii, xxviii)Google Scholar and in Duveen, and Klickstein, , op. cit. (93), pp. 52, 54.Google Scholar

¹¹² Black explained changes of state in terms of combined fire in his Lectures on the Elements of Chemistry, ed. Robison, J. (2 vols., Edinburgh. 1809), i. 49, 129, 157, 176, 192–5.Google Scholar Although there is some doubt as to whose ideas are stated in Black's Lectures, a statement of this particular version of Black's views appeared in the second edition of the Encyclopaedia Britannica (10 vols., Edinburgh, 1778–1783Google Scholar; ‘Congelation’, iii [1778], 2189Google Scholar; ‘Evaporation’, iv [1779], 2847, 2848Google Scholar; ‘Heat’, v [1780], 3539).Google Scholar However, the article of 1772 (loc. cit. [3]) states only that heat is absorbed and becomes hidden during changes of state. The same idea is contained in Cochrane, Thomas, Notes from Doctor Black's Lectures on Chemistry, 1767/8, ed. McKie, D. (Cheshire: Imperial Chemical Industries Ltd., 1966), pp. 12, 13, 15Google Scholar, and in the anonymous account of Black's ideas published in 1770: An Enquiry into the General Effects of Heat, with Observations on the Theories of Mixture (London), pp. 40, 48.Google Scholar

¹¹³ Lavoisier was not alone in explaining changes of state in terms of the combination of fire matter. In 1772 Wilcke published his theory of the latent heat of fusion; see McKie, and Heathcote, , op. cit. (33), pp. 78–94.Google Scholar Wilcke and Black seem to have arrived at the concept of latent heat by consideration of times and quantities of heat required to melt ice and snow (ibid., pp. 16, 78). A conclusion similar to Lavoisier's and based on the same kinds of evidence that Lavoisier used was published in 1772 in Deluc, Recherches sur les Modifications de l'Atmosphere (2 vols., Geneva). Deluc cited evaporative cooling and the condensation of water vapour on a cold surface to demonstrate that vaporization is caused by a combination of the matter of fire with water (ibid., i. 178, 180, 182–3, 264–5; ii. 175).

¹¹⁴ See a discussion of this point in Morris, , op. cit. (14), 378–9Google Scholar; cf. Guerlac, , op. cit. (14), pp. 380–1.Google Scholar

¹¹⁵ Cited in n. 2 above.

¹¹⁶ Fric, op. cit. (5), 142.Google Scholar

¹¹⁷ ibid., 152.

¹¹⁸ The major point on which Lavoisier and Crawford disagreed was on whether fire is combined or not.

¹¹⁹ Or Monge's interpretation?

¹²⁰ Mém. Acad. R. Sci. 1777, p. 420.Google Scholar

¹²¹ Mém. Acad. R. Sci. 1780, p. 358.Google Scholar

¹²² See for example his discussion of heat combined in various substances (ibid., pp. 394, 399–400). If Lavoisier wavered in his view, he did so only in the first half of this memoir.

¹²³ ‘Sur le phlogistique’ [1785], Mém. Acad. R. Sci. 1783, p. 524.Google Scholar

¹²⁴ Trailé, i. 6.Google Scholar

¹²⁵ Mémoires de Chimie, i. 2.Google Scholar

¹²⁶ Venel, , ‘Feu (Chimie)’, Encyclopédie, vi. 609Google Scholar; Macquer, , Elémens de Chymie-théorique (new edn., Paris, 1753), p. 16.Google Scholar For a discussion of Rouelle and his significance in this connexion, see Rappaport, R., ‘Rouelle and Stahl: the phlogistic revolution in France,’ Chymia, vii (1961), 76–7, 85–6.Google Scholar

¹²⁷ Indeed, Joseph Black attributed the qualities of softness, ductility, and malleability to latent heat (Lectures, i. 138–40).Google Scholar

¹²⁸ For example, the idea of opposing forces was stated by Boerhaave, (A New Method of Chemistry, trans. Shaw, P. [3rd edn., 2 vols., London, 1753], i. 246–7)Google Scholar and Turgot (op. cit. [11], p. 282).Google Scholar The latter (p. 277) described changes of state as nuances of the general expansive action of heat.

¹²⁹ Mémoires de Chimie, i. 404–11.Google Scholar These fluids differ from gases in that they have varying abilities to penetrate the pores of different substances such as glass and metals. Caloric is more subtle than the electric and magnetic fluids.

¹³⁰ Traité, ii. 526–7.Google Scholar

¹³¹ ‘Sur le phlogistique’ [1785], Mém. Acad. R. Sci. 1783, p. 509.Google Scholar As Seguin remarked, ‘notre idée se refuse à l'existence d'un corps dont la pesanteur est absolument nulle’ (Annales de Chimie, iii [1789], 185Google Scholar; cf. a similar statement by him in Lavoisier, 's Mémoires de Chimie, i. 158–9, note).Google Scholar

¹³² Mémoires de Chimie, i. 408.Google Scholar Cf. similar statements in ‘Mémoire dans lequel on a pour objet de prouver que l'eau n'est point une substance simple, un élément proprement dit, mais qu'elle est susceptible de décomposition & de récomposition, Mém. Acad. R. Sci. 1781, p. 473Google Scholar; ‘Nouvelles réflexions sur l'augmentation de poids qu'acquièrent en brûlant le soufre & le phosphore, & sur la cause à laquelle on doit l'attribuer’, Mém. Acad. R. Sci. 1783, pp. 419–21Google Scholar; ‘Sur la pesanteur de la matière de la chaleur’, Oeuvres, v. 293.Google Scholar

¹³³ Macquer had remarked that without heat all matter would be ‘une seule masse immense, homogene, & d'une dureté absolue’ (Dictionnaire de Chymie [2 vols., Paris, 1766], i. 498).Google Scholar

¹³⁴ Traité, i. 24–7.Google Scholar Regarding repulsion as being in reality an effect of attraction, see Seguin's views in Lavoisier, 's Mémoires de Chimie, i. 158–9Google Scholar, note.

¹³⁵ Mémoires de Chimie, i. 6–7, 19–25.Google Scholar

¹³⁶ For example see Boerhaave, , Method of Chemistry, i. 359–64Google Scholar; and Macquer, , Dictionnaire (1766), i. 498; ii. 203.Google Scholar This feature gave Lavoisier's predecessors greater-latitude in accounting for heat phenomena, for temperature could be related to either the quantity of fire matter or the degree of its own internal motion.

¹³⁷ Fric, op. cit. (5), 142.Google Scholar

¹³⁸ The motion feature was absent in most material theories of heat discussed during the last quarter of the century. This resulted in a weakness in the explanations of mechanical production of heat, a weakness not present in the earlier material heat theories and one which Count Rumford exploited in his unsuccessful attempt to revive a vibratory theory in 1798. Most writers simply ignored the question of the motion of fire matter. The few who argued against it did so on the grounds that fire, being matter, should not possess a property which is not characteristic of matter in general; see ‘Fire’, Encyclopaedia Britannica (2nd edn.), iv (1779), 3003Google Scholar; and Pierre, Jean Baptistede Monet, Antoinede Lamarck, , Recherches sur les Causes des Principaux Faits Physiques … (2 vols., Paris, an II [1794]), i. 51, 66–7.Google Scholar

¹³⁹ ‘Sur la combustion’ [1777], Mém,. Acad. R. Sci. 1777, p. 598.Google Scholar

¹⁴⁰ According to Macquer (Elémens de Chymie-théorique [1753], P. 16)Google Scholar, fire can be fixed only in the form of phlogiston which does not change the state of either solids or fluids; see also n. 128.

¹⁴¹ Fric, op. cit. (5), 149–50.Google Scholar Cf. the same argument in the Opuscules, p. 280.Google Scholar

¹⁴² The first volume of Mémoires de Chimie comes closest to conforming to this description and these papers together contain a discussion of virtually all Lavoisier had to say on the subject. Yet in spite of the breadth indicated by the titles of the various memoirs, the treatment in many is very restricted.

¹⁴³ The association was also chemical. Lavoisier's treatment of the heat phenomena of chemical reactions most commonly occurs in a context discussing the reactions of oxygen gas. In part as a result of this, he gives the impression that he believed caloric and oxygen to have a unique relationship which is maintained even when both are combined with other components. In this context, caloric is never treated as simply one of several chemical constituents united in a given compound. Caloric in these compounds is that retained by oxygen when the latter combines, and it is by virtue of its prior union with oxygen that caloric is carried over and becomes a constituent in other combinations: vital air ‘retient plus ou moins de calorique, suivant la nature des substances avec lesquelles il se combine’ (Mémoires de Chimie, i. 140).Google Scholar

¹⁴⁴ Quoted in Eyles, V. A., ‘The evolution of a chemist, Sir James Hall, Bt. F.R.S., P.R.S.E., of Dunglass, Haddingtonshire (1761–1832), and his relations with Joseph Black, Antoine Lavoisier, and other scientists of the period’, Annals of Science, xix (1963), 167, 169–70.Google Scholar

¹⁴⁵ ‘Sur la combustion des chandelles’, Mém. Acad. R. Sci. 1777, P. 204Google Scholar; cf. a similar statement, ibid., p. 399 n.

¹⁴⁶ ‘Introduction et plan d'un deuxiéme volume des Opuscules Physiques et Chimiques’, Oeuvres, v. 268.Google Scholar

¹⁴⁷ Nomenclature Chimique, pp. 292–7.Google Scholar

¹⁴⁸ Kirwan, Richard, An Essay on Phlogiston and the Constitution of Acids [1784] … To which are added Notes Exhibiting and Defending the Antiphlogistic Theory and Annexed to the French Edition of this Work [1788] … With Additional Remarks by the Author, trans. Nicholson, W. (London, 1789 [London: Cass, 1968]), pp. 11–22Google Scholar; cf. similar arguments by Lavoisier, , pp. 45–52.Google Scholar