Séguin, Armand

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(b. Paris, France, March 1767; d. Paris, 24 January 1835)

chemistry, chemical technology, physiology.

Séguin’s father was the treasurer (apparently corrupt) of the duke of Orléans. Althought little is known of his education, it is evident that he had some training in the sciences, for by the mid-1780’s he had become part of Lavoisier’s circle. Séguin was Lavoisier’s assistant from 1789 until the latter’s death in 1794. During this time, Séguin produced those memoris (some written with Lavoisier) on heat and respiration for which he is best known. In 1796 he assisted Mme Lavoisier in preparing her husband’s memoirs for publication. But they soon ended this collaboration because Séguin was unwilling to denounce in print Lavoisier’s executioners and because, in a preface prepared by Séguin, he took more credit for Lavoisier’s later work than Mme Lavoisier rightly thought he deserved.

Meanwhile, Séguin had become director of a tanning works at Sévres, an enterprise that was based on processes of his own devising and that won the contract to supply the revolutionary armies with boot leather. Although Séguin made no fundamental innovations in tanning, he found several ways to rationalize and accelerate the operation, being unhampered by craft my steries. He shortened the time for tanning hides from more than a year to a few weeks. Understandably, he received support, encouragement, and subsidies from the Comité de Salut Public.

Séguin made money out of the wars, but Napoleon, who had no love for profiteers, later reduced his fortune by taxes and fines (even to the point of imprisoning him), but did not succeed in impoverishing him. Séguin survived the Empire and Restoration and lived thereafter the life of an eccentric, Balzacian rentier, devoting most of his intellectual energies after 1815 to the composition of pamphlets on government finances. He was also devoted to horseracing and wrote a number of works on that subject.

Séguin’s scientific contributions were made chiefly in collaboration with others. In the work he published with Fourcroy and Vauquelin on the synthesis of water, and in the papers he wrote with, or under the tutelage of, Lavoisier, he wrote crisply and authoritatively. Thereafter he lost his grip, and, with the exception of his research on tannin, his independent investigations were trivial. Although he contributed a number of “first memoirs” on several subjects, mostly pharmaceutical, to the Annales de chimie in 1814, these papers had been written years before and were never followed up.

In May 1790 Séguin read to the Académie des Sciences the report on the larg-scale synthesis of water carried out in Fourcroy’s laboratory by himself, Fourcroy, and Vauquelin. The purpose of this experiment was to establish finally that water is composed only of hydrogen and oxygen and that the weight of water is fully accounted for by the weights of the two gases. They also sought to determine accurately the combining ratio of the components of water, an especially important constant in oxygen chemistry. They found that the ratio hydrogen: oxygen is 2.052:1 by volume and 14.338:85.662 by weight. (The discrepancies from the true figure probably arose from the difficulties of weighing the gases.)

Séguin’s papers on respiration, animal heat, and caloric are all derivative from Lavoisier’s work and ideas, although the evidence suggests that Séguin was an enthusiastic collaborator and one who made the master’s ideas his own. Séguin’sd series of papers in caloric competently summarized and systematized Lavoisier’s later thinking on the subject and also, as Robert Fox has recently shown, thoroughly refuted the Irvinist theory of caloric. This work helped to consolidate the Lavoisier Laplace version of caloric theory and thus paved the way for the developments of that theory in the following three decades.


I. Original Works, séguien’ works are listed in the Royal Society Catalogue of Printed Papers, V. 628–629: those which he contributed to Lavoisier’s Mémoires de chimie, 2 vols. (Paris. 1805), are listed in Denis I. Duveen and Herbert S. Klickstein, A Bibliography of the Works of Antoine Laurent Lavoisier 1743–1794(London, 1954), 204–214, His papers written with Lavoisier are “Premier mémoire sur la respirataion,” in Mémoires de l’ Acadeémie reyale des sceience (1789), 566–484: “Premier mémoire sur la transpiration des animaux,” ibid, (1790), 601–612; “Second mémoire sur la transpiration,” in Annales de chimie, 90 (12814), 5–28::Second mémoire sur la respiration,” ibid., 91 (1814), 318–334; and “Sur la respiration des animauzx,” in Lavoisier, Mémoires de chimie, II, 52–64 (in the separately paginated last section), See also “Observation géneérales sur la respiration et sur la cheleur animals,” in Observations sur la physique, sur;’histoire natrurelle et sur les arts, 37 (1790), 467–472. Séguin’s paper with Fourcroy and Vauquelein is “Mémorie sur la combustion du gaz hydrogéne dans des vaisseaux clos,” in Annales de chimie, 8 (1791), 230–307; reprinted in Lovoisier op. cit., 11, 313–413.

The Bibliothèque Natioanle Catague des livers imprimés Séguin’s financial and miscellaneous writings.

II. Scondary Literature. On Séguin and his work, see Michaudm ed., Biographie universelle; and J. R. Partington, History of Chemistryu, III (London, 1962), 106–107, For his contribution to the theory of heat, see Robert Fox, Caloric Theory of Gases (Oxford, 1971), chap, 2, especially pp. 38–39: for relatiions with Mme Lavoisier, see Edouard Grimaux, Lavososer (Paris, 1888), 330–336, and Duvenn and Klickstein, op, cit., 199–204; and for his on tanning, see C. H. Leliever and Pelletier, “Rapport au Comite de Dault Public, sur les noveaux noyens de tanner les cuirs, proposés par le cit, Armand Séguin,” in Annuals chimie,20 (1797), 15–77.

Stuart Pierson