(b. Dijon, France, end of 1778 or beginning of 1779; d. Paris, France, 21 November 1841),
When Clément had finished his primary education in Dijon, he went to Paris as clerk to an uncle who was a notary. Since childhood he had devoted all his leisure time to chemistry, and in Paris he was able to attend the courses at the Jardin des Plantes. Chance altered the course of his career; he won the lottery and from then on was able to devote himself entirely to chemistry. He developed quite extensive connections within the first group to be promoted at the École Polytechnique and then throughout the scientific world. He later married the daughter of Charles-Bernard Desormes, an assistant in the laboratory of Guyton de Morveau at the Ecole Polytechnique. A lasting scientific collaboration was established between the two men, and Clément often used the name Clément-Desormes. Hence, some accounts report that Clément and Desormes were the same person.
The scientific work of Clément and Desormes was numerous and varied; here we must be content to enumerate only the most important. It began in 1801–1802 with the exact determination of the composition of carbon monoxide and of carbon disulfide. A controversy took place on this subject with Berthollet, who harbored a lasting grudge against Clément. Berthollet held that carbon could not exist without containing hydrogen and that carbon disulfide was identical to hydrogen sulfide, and he presupposed “water combined in gases” to take account of the composition of certain barium salts, for which Clément and Desormes gave the correct analysis. In 1806 the analysis of ultramarine was achieved; by establishing definitely that the blue color was not due to iron, Clément prepared the way for the synthesis that J. B. Guimet carried out twenty-one years later.
Research on alum in the same year established that the preference given to Italian alums was based solely on prejudice for certain purely exterior characteristics: for example, the color resulting from inert impurities was considered essential; consequently, alum that was too pure was not accepted. This finding permitted the development of a French alum industry. Also in this period Clément achieved one of his most remarkable successes by giving an exact account of the chemical reactions produced in the manufacture of sulfuric acid; the quality of its production was improved, which aided the entire chemical industry.
Another part of the work of Clément and Desormes concerned the study of heat (ca. 1812–1819). Their investigations led them to give a number of a satisfactory order of magnitude for absolute zero; their attempts to estimate the quantities of heat existing outside of a material support seem to have been severely criticized by Gay-Lussac, even though the law he formulated was the basis for their calculations. In addition, they published papers on the mechanical power of fire. They hoped to discover its basis in the law, named for Watt, according to which the quantity of heat in a given weight of water vapor is independent of its temperature and volume—a law that the limits of contemporary practice allowed one to consider as exact. Using this relationship and Gay-Lussac’s law, Clément and Desormes correctly deduced that it is advantageous to operate the machine at high pressures and to allow maximum expansion to take place. From the lecture notes of a student at the Conservatoire des Arts et Métiers, it is known that Sadi Carnot attended Clément’s lectures; it is also known that the latter lent Carnot the manuscript of an important memoir of 1819, unpublished and now lost, in which the detailed results of his work on steam engines were presented (the 1819 memoir is cited many times in Carnot’s Réflexions sur la puissance motrice du feu, which Clément recommended that his students read when it appeared in 1824). It is certain that Carnot owed a great deal to Clément, beginning perhaps with his choice of subject matter and title.
The year 1819, moreover, marked the peak of Clément’s scientific career; he became a professor at the Conservatoire des Arts et Métiers, holding one of the three chairs in higher technical education established that year. Clément was all the more suited because he was an experienced business manager; he had to his credit, among other things, a beet-sugar refinery, a distillery that manufactured alcohol from potatoes, and an alum refinery. During his later years Clément acquired the habit of traveling during the summer to study the principal business enterprises in France and abroad. As a result of his competence, he was sought as consulting engineer by, among others, the Salines de I’Est and the Compagnie de Saint-Gobain. It was with the latter that he achieved a fatal success: he had made a contract on a percentage basis, which obliged the company to pay him considerable sums, and it therefore terminated its connection with him as soon as the processes he introduced were sufficiently developed for his services to be unnecessary. This disappointment seems to have shortened Clément’s life, for soon afterward, in 1839, he had a stroke, following which he was deprived of his faculties. He died suddenly on 21 November 1841.
I. Original Works. Almost all of Clément’s works were presented to the Institute and are enumerated from day to day in the Procès-verbaux des séances de l’Académie tenues depuis la fondation de l’Institut jusqu’au mois d’août 1835, 10 vols. (Hendaye, 1910–1922).
Clément’s other publications include the following, without collaborators: “Remarques sur l’évaporation de l’eau par l’air chaud. Observations sur un procédé économique de M. Curaudau inséré dans les Annales des arts et manufactures, no.118 (avril 1811), “in Annales des chimie, 79 (1811), 84–89; “Sur la quantité de matière ligneuse existante dans quelques racines et dans quelques fruits. Note lue le 3 fevrier 1816 à la Société Philomatique,” in Annales de chimie et de physique, 1 (1816), 173–176; “Sur la fermentation alcoolique,” ibid., 5 (25 Aug. 1817), 422–423; Appréciation du procédé d’éclairage par le gaz hydrogène du charbon de terre par M. Clément-Desormes, manufacturier (Paris, 1819): “Sur un procédé pour découvrir la magnésie.” in Annales de chimie et de physique, 20 (1822), 333; “Sur la découverte d’une pierre propre à la fabrication de ciment romain,” ibid24 (10 Oct. 1823), 104–106; “Cascade chimique,” in Annales des mines, 9 (1824), 194–196; “Note sur des lingots de cuivre obtenus par la voie humide,” in Annales de chimie et de physique, 27 (1824), 440–442; Théorie générale de la puissance mécanique de la vapeur d’eau (n.p., n.d. [Paris 1826]), of which the only copy is in Musée Carnavalet, Paris série topographique, grands cartons XIV; Programme du cours de chimie appliquée ([Paris], 1829); and Influence du bas prix du sel sur sa consommation (n.p., 1834). Another published work is Manuel de chimie appliquée (n.p., n.d.); a work available in MS form is “Travaux de M. Clément,” with an autobiography written when he was a candidate for the Institute, undoubtedly 27 January 1823; an original autograph, presented to the Conservatoire des Arts et Métiers on 20 September 1854 by Anselme Payen is in the Conservatory’s archives—ser. 10, liasse 494, presently in the Conservatory’s library. There is also “Chimie industrielle, Journal des cours de 1825 à 1830,” with introductory material, table of contents, and remarks by J. M. Baudot, 3 MS vols. at the library of the Conservatory: cote 8° Fa 40.
In collaboration with Charles-Bernard Desormes he wrote “Sur la réduction des métaux par le charbon. Anomalie qu’elle présente. Découverte d’un gaz nouveau,” ibid38 (an IX), 285–290, on carbon monoxide; “Memoire sur la réduction de l’oxyde blanc de zinc par le charbon et sur le gaz oxyde qui s’en dégage,” in Annales de chimie39 (an IX), 26–64; “Expériences sur le charbon,” ibid42 (an X), 121–152, containing an announcement of carbon disulfide; “Experiences sur l’eau contenue dans les gaz et sur quelques sels barytiques,” ibid43 (an X), 284–305; “Mémoire sur l’outremer lu à l’Institut le 27 janvier 1806,” ibid., 57 (1806), 317–326; “Théorie sur la fabrication de l’acide sulphurique. Mémoire lu à l’Institut le 20 janvier 1806,” ibid59 (1806), 329–339; “Fabrication du blanc de plomb (procédé de Montgolfier),” ibid80 (1811), 326–329; “Sur le nouveau procédé de congélation de M. Leslie, et sur les applications de ce procédé considéré comme un moyen d’évaporation, ibid78 (1811), 183–202; “De l’épuration des corps par la cristallisatioin,” ibid92 (1814), 248–253; “Détermination expérimentale du zéro absolu de la chaleur et du calorique spécifique des gaz,” in Journal de physique, 89 (1819), 321–346, 428–455, reprinted in shorter form in Bibliothèque universelle des sciences année 5, 13 (1820), 95–111; and “Mémoire sur la théorie des machines a feu. Extrait,” in Bulletin des sciences par la société philomatique de Paris (1819), 115–118.
Another work done in collaboration, this time with L. de Freycinet, is “Mémoire sur la distillation de l’eau de mer et sur les avantages qui en resultent pour la navigation,” in Annales de chimie et de physique4 (1817), 225–241.
II. Secondary Literature. On Clément or his work, see Jean Chaptal and N.-L. Vauquelin, “Rapport du mémoire sur l’alun de MM. Desormes et Clément, fait à l’Institut le 27 janvier 1806,” in Annales de chimie, 57 (1806), 327–333; Pierre Costabel, “Le ‘Calorique du vide’ de Clément et Desormes (1812–1819),” in Archives internationales d’histoire des sciences, 21 (1968), 3–14; Charles Dunoyer, “Clément-Desormes,” in Journal des economistes, 1 (1842), 208–213; Louis-Bernard Guyton de Morveau and Marie Riche de Prony, “Rapport sur un appareil établi à la Monnaie pour faire consumer la fumée des machines (Institut, 16 janvier 1809),” in Annales de chimie69 (1809), 189–203; Anselme Payen, “Notice sur Clément-Desormes,” in Bulletin de la Société d’encouragement41 (1842), 377–380; Jacques Payen, “Une source de la pensée de Sadi Carnot,” in Archives internationales d’histoire des sciences, 21 (1968), 15–37; paul Thénard, Traité de Chimie 5th ed., I (Paris, 1827), 77–81, an edition of a fragment of the memoir of 1819 on machines à feu—see also the commentary added by Thénard, pp. 81–82.