Geoffroy, Étienne François

(b. Paris, France, 13 February 1612; d. Paris, 6 January 1731)

chemistry, medicine.

Known as Geoffroy the Elder (l’Aîné) to distinguish him from his brother Claude Joseph, he was the son of Matthieu François Geoffroy, a wealthy pharmacist who had been a Paris alderman, and Louise de Vaux, daughter of a well-known surgeon. Such scientists as Wilhelm Homberg and J. D. Cassini visited their home, giving demonstrations and lectures that supplemented Geoffroy education, His father, the fourth in a respected dynasty of pharmacists, hoping that Geoffroy would eventually take over the family business, sent him to Montpellier in 1692 for a year to learn pharmacy from a colleague, Pierre Sanche, whose son came to Paris. While in Montpellier, Geoffroy attended courses at the medical school; and although he qualified as a pharmacist in 1694 after his return to Paris, his real ambition was to become a physician. With his father’s consent he therefore turned to the study of medicine.

While still a Student Geoffroy was chosen as medical adviser by the comte de Talland, French ambassador extraordinary to England; and in 1698 he spent several months in London, where he became friendly with Hans Sloane. He was made a fellow of the Royal Society, of which Sloane was secretary; and in January 1699, after his return to Paris he was elected to the Academic des Sciences the student of Homberg; he became an associé later in 1699 and Pensionnaire in 1715. When first elected, he offered to keep the Academy informed of scientific developments in England, and his correspondence with Sloane became a valuable medium for the transmission of scientific news between the two countries.

On his way home from London, Geoffroy had visited Holland; and in 1700 he made another long journey, to Italy, He eventually graduated M.D. at Paris in 1704 and began to practice a few years later. He acquired a considerable reputation and was often consulted by other physicians.

Geoffroy succeeded J. P. de Tournefort as professor of medicine at the Collège Royal (now the Collége de France) in 1709 and retained the chair until his death; but his lecturing career had begun in 1707, when he first deputized for G.-C. Fagan, professor of chemistry at the Jardin du Roi. Until 1710 he shared this duty with Louis Lemery and Claude Berger; then Berger acted alone until his death in 1712, when Fagan retired completely from the chair and Geoffroy was appointed. Geoffroy normally lectured on materia medica for two or three hours immediately after his two-hour lecture on chemistry, a feat that earned the praise of Bernard de Fontenelle; the comments of the students are not available.

In 1726 Geoffroy was elected dean of the Paris Faculty of Medicine, and after the customary two-year period he was reelected, serving until 1729, at a time when there was a serious dispute between the physicians and surgeons. The strains of this office, together with his chairs and his practice, weakened his health. He retired from the Jardin du Roi in 1730, and-within a year he died of consumption at the age of fifty-eight. Risson, Etienne Louis Geoffroy, became well known as a naturalist and was elected to the Institut de France in 1798.

A new Paris pharmacopoeia, Codex medicamentarius seu pharmacopoeia parisiensis, was published by the Faculty of Medicine in 1732 under the deanship of H. T. Baron. Largely the work of Geoffroy, it contained many chemical remedies in addition to the traditional galenicals, as did Geoffroy’s unfinished book on materia medica, based on his lectures. The part that he had dictated, containing medicaments from the mineral kingdom and part of the vegetable kingdom, was published in Latin as Tractatus de materia medica in 1741 and was translated into French in 1743. Geoffroy’s treatment of the vegetable kingdom was interesting. Exotic, plants were not usually imported whole, so he classified them under such headings as roots, barks, and leaves, since these were the parts used in medicine; but he described the whole plant in the case of those native to France. Almost always he included the results of qualitative and quantitative analysis by distillation, recording the nature and amount of each oil, phlegm, salt, or earth obtained; and he endeavored to relate the medicinal properties to the products of analysis. This approach to the study or vegetable remedies, with the implication that the products of distillation were originally present as such in the plant, had been introduced by earlier chemists at the Academy; and many such analyses are recorded in its minute books. By the end of his life, though, Geoffroy had lost faith in the method, according to the editors of the supplement to his Materia medica, who excluded these analytical results.

Geoffroy’s first publication a study of heat effects observed when saline substances were mixed (1700), is of interest as an early attempt to use the thermometer in chemistry; but his results were inconclusive and it is clear that his air thermometer responded too slowly to temperature changes. He soon entered a field of experimental chemistry which he related to a theory of matter.

Homberg had “decomposed?” common sulfur into an acid, a bituminous substance, and an earth. Geoffroy found in 1704 that it could be re-formed by heating oil of vitriol (sulfuric acid) and turpentine; after distillation iron, detected with a magnet, was ’present in the residue. In 1705 Geoffroy also found iron in the ashes of all vegetable matter, although it was not detectable in the original plant: he believed that the iron had been formed during these processes, a “sulfurous principle” being common to vegetable matter and metals and giving metals their properties of fusibility and ductility. Louis Lemery objected to this theory and argued that the iron was present all the time in the oil of vitriol or turpentine, and in the vegetable matter that had been burned (Mémoires de l’Académie royale des sciences for 1707 [1708], 5-11). He claimed that Geoffroy’s reasoning was unsound, for in some circumstances—when dissolve in acid and then crystallized for example-iron could not be detected with a magnet although it was certainly present (Histoire de l’Académie royale des sciences for 1708 [1709], 61-65). Yet Geoffroy persisted in’ his belief, and in 1720 he identified his “sulfurous principle” with Georg Stahl’s phlogiston.

On fermentation, urine produced volatile alkali; and in 1711 Geoffroy considered that the acid in urine had been converted into alkali. He also believed that alkali could be formed from mineral acids; he explained these changes as well as the formation of iron from vegetable matter, by a theory which was elaborated in his Materia medica but is also mentioned in some of his earlier publications.

Geoffroy recognized three “very simple substances”: fire, which could exist only in combination with the others; water, composed of hard, smooth, oval or wedge-shaped particles that dissolved solids by forcing their particles apart; and earth, composed of irregular particles with many pores between them. These three combined to’ farm two “principles:’ salt And sulfur, which were the usual products of analysis, Salt existed in two main forms, acid and alkali, which were interconvertible because they differed in the way their constituent fire, water, and earth were combined: the particles of acids were pointed at both ends; those of alkalies were spherical with projecting points that joined together, forming a porous globule into which acid particles could enter. Sulfur was formed by the combination of salt with more fire, water, and earth; this combination could take place in vegetables or animals, or beneath the ground, where, according to the proportions of the constituents, the product was one of a variety of substances, such as petroleum, coal, common sulfur, or a metal.

It was well known before Geoffroy’s time that certain substances could displace others from compounds; but in 1718 he advanced the first general proposition that if two substances in combination are approached by a third with which one of them has a greater relation (rapport), then that one will combine with the third, leaving the other free. He accompanied this with a sixteen-column table in which, using symbols, he showed the order of displacement of some common substances. The first column referred to compounds of mineral acids, with which fixed alkali (soda and potash were not yet distinguished) had the greatest relation, followed by volatile alkali (ammonia), absorbent earth (chalk and such), and metals. Since the order in which the metals displaced each other was not the same for all acids, the next three columns were devoted to the individual acids; and their reactions with metals. There followed columns for absorbent earth, fixed alkali, volatile alkali, metals in combination with acids, and common sulfur; and then six columns for the “compounds” of the metals with each other and one for water in relation to salt and alcohol.

No details were given by Geoffray of the experiments an which his table was based and in 1720 he had to reply to same criticisms. For example one critic challenged his statement that absorbent earth came below volatile alkali in the first column, for it was well known that lime expelled volatile alkali from salammoniac (ammonium chloride). Geoffroy replied that although it was formed by heating chalk, lime was not itself a pure absorbent earth; rather, it contained sharp and caustic particles of alkali, which might have been formed from acid in the wood that was bunted when the lime was made, or perhaps from “aluminous vitriolic acid” present in the original chalk. This opinion was criticized by Louis Lemery, who, like his father. Nicolas Lemery, believed that lime owed its causticity to fire particles (Histoire del’Académieroyale des sciences for 1720 [1722], 33). Thus it is easy to understand why Geoffroy’s table was not elaborated until after about 1750, when ideas on the nature of acids, alkalies, and earths were more clearly defined.

In 1718 and again in 1720 Geoffroy referred only to “rapport” and did not use the words “affinity” or “attraction.” There have been suggestions that he was influenced by Newton’s theory that chemical reactions were caused by attration between particles, but his detailed account of pointed and porous particules that combine by interlocking seems to make it clear that his ideas were akin to those of Descartes, Pierre Gassendi, Nicolas Lemery, and Nicolaas Hartseoker, and that he did not belong to the Newtonian school of chemists.

BIBLIOGRAPHY

I. Original Works. According to Fontenelle, Geoffroy was the principal author of Codex medicamentarius seu pharmacopoeia parisiensis (Paris, 1732). THe first version of his work on materia medica to be published was ATreatise of the Fossil, Vegetable and Animal Substances, That Are Made Use of in Physick (London, 1736), a partial English trans. by G. Douglas of a MS of Geoffroy’s lectures, which were delivered in Latin at the Collége Royal; this contains a short account of the animal kingdom, which is not in the Latin and French eds., and an English version of Fontenelle’s “Éloge.” The Latin text was published (by Étienne Chardon de Courcelles, according to Dorveaux) as Tractatus de materia medica 3 vols. (Paris, 1741); vol. I includes the Latin texts of Fontenelle’s “Éloge” and Geoffroy’s papers written in 1713, 1718, and 1720. A French trans. (by A. Bergier, according to Dorveaux) appeared as Traitéde matière Médicale, 7 vols. (paris, 1743; new. ed. [unaltered], 1757. Vol. I contains Fontenelle’s “Éloge,” Geoffroy’s papers written in 1713, 1718, and 1720, and a French trans. of one of his medical these: “Question, si l’homme a commencé par être ver.” The Latin and French eds. of Materia medica stop where Geoffroy’s MS ended, at the word “Melilotus” in the alphabetifcal list of indigenous plants. The vegetable kingdom was completed in Suite de la matière de M. Geoffroy, par M***, docteur en médecine, 3 vols. (Paris, 1750); the authors of this were apparently the men who published an account of the animal kingdom in Suite de la matière mèdicale de M. Geoffroy, par Mrs Arnault de Nobleville & Salerne, mèdecins d’Orléans, 7 vols. (Paris, 1756-1757). They claimed to follow Geoffroy’s order but added new material and acknowledged their indebtedness to Bernard de Jussieu and others.

Seventeen papers read by Geoffroy to the Académie des Sciences are listed in Poggendorff, I, 873-874. The most important, to which reference has been made above, are “Observations syr lkes disolutions et sur les fermentations que l’on peut appeller froide,” in Mémoires de l’Acaémie royale des sciences for 1700 (1703), 110-121; “Maniêre de semblables substances, avec quelques conjectures sur la composition des méltaux,” ibid, for 1704 (1706), 278-286; “Problème de chimie: Trouver des cendres qui ne contienent aucunes parcelles de fer,” ibid., for 1705 (1706), 362-363; “Éclaircissemens sur la production artificielle du fer, & sur la composition des autres métaux, faites avec le verre ardent du Palais Royal,” ibid, for 1709 (1711), 162-176; “Observations sur le vitriol et le fer,” ibid, for sels alkalis volatiles urineux,” ibid., for 1717 (1719), 226-238; “Table des différens rapports observés en chymie enter différens substances,” ibid., for 1718 (1719), 202-212; and “Éclaircissemens sur la table inserée dans les Mémoires de 1718, concernant les rapports observés entre différentes substances,” ibid., for 1720 (1722), 20-34. Some of his letters to Sloane were printed, in part, in Philosophical Transactions of the Royal society and are listed in P. H. Maty, A Genral Index to the Philosophical Transactions (London, 1787) pp. 633-634.

II. Secondary Literature. A general account of Geoffroy’s life is in Bernard de Fontenelle, “Éloge de M. Geoffroy,” in Histoire de l’Académie royale des sciences for 1731 (1733), 93-100. Additional information is given by P. Dorveaux,”Étienne-François Geoffroy,” in Revue d’histoire de la pharmacie, 2 (1931), 118-126; J. P. Contant, Enseignement de la chimie au Jardin Royal des Plantes de Paris (Cahors, 1952), pp.55-57; and J. Torlais, “Le Collège Royal,” in R. Taton, ed., Enseignement er diffusion des sciences en France au XVIII^e siècle (Paris, 1964), pp. 261-286. Geoffroy’s relations with British scientists (with extracts from his letters to Sloane which are now in the British Museum and the Royal Society) are discussed by I. B. Cohen, “Isaac Newton, Hans Sloane and the Académie Royale des Sciences,” in I. B. Cohen and R. Taton, eds., Mélanges Alexandre Koyré (Paris, 1964), I, 61-116; Cohen’s description of Geoffroy as “one of Newton’s chemical disciples” is disputed by W. A. Smeaton, “E. F. Geoffroy Was not a Newtonian Chemist,” in Ambix, 18 (1971), 212-214. A good account of tables of affinity is given by A. M. Ducan, “Some Theoretical Aspects of Eighteenth century Tables of Affinity,” in Annals of Science, 18 (1962), 177-194, 217-232.

W. A. Smeaton