Bravais, Auguste

(b. Annonay, France, 23 August 1811; d. Le Chesnay, France, 30 March 1863)

botany, physics, astronomy, crystallography.

The ninth of ten children born to François–Victor Bravais, a physican, and Aurélie–Adelaïde Thomé, Auguste completed his classical education at the Collège Stanislas, Paris, in 1827, winning honorable mention in mathematics in the general competitive examination, He returned to Annonay and failed the polytechnical examination in 1828; after a year of special mathematics at the cllége St.–Louis, he won first prize in mathematics in the general competitive examination and was accepted at the École Polytechnique. He led his class at the end of his first year, and his academic record the next year made him eligible for any technical corps except mining. Since he wanted to participate in exploration, he chose to enter the navy. Bravais became a first–class cadet in 1831 and was sent to the Toulon naval district. He shipped out in January 1832, sailed the Mediterranean, and that April was assigned to map the coast of Algeria.

During his leaves in Annonay (November 1833–June 1835) Bravais studied plant organography with his brother Louis and his friend Charles Marins. The brothers’ publications on this subject won them membership in the Société Philomathique de Paris. Auguste’s work on shipboard led him to consider various methods of nautical surveying and the stability of ships; these were the subjects of his doctoral thesis, which he presented at Lyons in 1837. Shortly afterward he and Martins were assigned to the Commission Scientifique du Nord and sailed in June 1838 with the expedition that landed near North Cape.

While in Norwegian Lapland (August 1838 to September 1839), Bravis and the other Physicists from the commission made numerous observation in astronomy, meteorology, and terrestrial magnetism. He noticed that a certain alga, Fucus vesiculosus, formed a yellowish area whose upper limit always occurred at the same height above sea level; this served as a point of reference for surveying ancient shorelines. Accompanied by Martins, Bravais returned overland to Paris, arriving in January 1840. Immediately afterward the navy assigned him to publish an account of the expedition; the volumes dealing with meteorolgy, terrestrial magnetism, the northern lights, botanical geography, astronomy, and hydrography are largely his own work.

The navy authorized Bravais to teach astronomy at the Faculté des Sciences at Lyons in 1841. Shortly after his arrival, he and J. Fournet founded the Commission Hydrométrique des Orages et Météorologique de Lyon. Bravais climbed the Faulhorn in 1841 and 1842 with his brother Louis and Martins, in order to make observations. He was elected a member of the Acadèmie Royale des Sciences, Belles–Lettres et Arts de Lyon in 1844, and later that year the minister of public education entrusted him with a scientific mission in the Alps: accompanied by Martins, he climbed Mont Blanc and, once again, the Faulhorn. During his stay in Lyons he wrote the segment of Patria that contains a survey of verified falls of meteorites in France from 1198 until 1842.

Bravais was appointed professor of physics at the École Ploytechnique in 1845. Among the many communications he sent to the Académie des Sciences, the ones that drew the most attention were those of 1848 and 1849. They concerned reticular groupings and were based on speculations arising from a paper by Delafosse on the meaning of hemihedrism in crystals. The Academy admitted Bravais to its geography and navigation section in 1854.

The relationship between the external forms of crystals and an internal periodic corpuscular structure had been discussed by Kepler, Descartes, Hooke, and Huygens but was neglected in the eighteenth century for studies of the external forms alone, in the manner of Steno’s Prodromus. Afte Romé de I’Isle and Haüy attention was agin directed to internal structure seen as the repetition of fundamental polyhedral nuclei. In an exhaustive study of the properties of lattices (1848), Bravais derived the fourteen possible arrangements of points in space. The Bravais lattices effectively combined earlier concepts of periodicity with Haüy’s law of rational intercepts. (A.J. Shaler’s English translation of this fundamental paper was published in 1949 as Memoir no. 1 of the Crystallographic Society of America.)

In the Études cristallographiques (1866), Bravais concentrated on the relationships between the ideal lattice and the material crystal. He proposed to locate his lattice points at the centers of gravity of congruent molecular polyhedra (p. 196). His analysis of the symmetry of the molecular polyhedra (the thirty–two point groups had been derived by Hessel in 1830) led to the later derivation of the space groups by Barlow, Schönflies, and Fedorow. The Bravais molecular poluhedra, repeated in parallel orientation in the same way as the points of the Bravais lattice, constituted the modern representation of the atomic structure of crystals. Each peak of the polyhedron was “a center or pole of force” (ibid.), which Cauchy, in a remarkable report introducing the paper, under stood as an atom of a particular species. The Bravais rule that referred the most prominent planes of the crystal and the planes of cleavage to the nets of the Bravais lattice with the greatest reticular density (concentration of points) afforded a method by which mineralogists could determine lattice types and, in the simplest cases, structures. Bravais himself applied the rule to most mineral species with excellent but not perfect results.

Only constant work allowed Bravais to carry on extensive studies of the many different subjects that aroused his curiosity. He was, however, not able to bear such a strain indefinitely. He became seriously ill in 1856, resigned from his post at the École Polytechnique, and retired from the navy in 1857. His wife tried to nurse him back to health; on his death she withdrew to the Convent des Clarisses, in Versailles, of which she was founder.

Bravais’s work, continued by Friedel, Tammann, Bralow, and others, provided the mathematical and conceptual basis for the determination of crystal structures after Laue’s discovery of X–ray diffraction in 1911. The intensive development of solid–state physics in recent times had publicized Bravasi’s role in the origin of the application of the mathematics of symmetry and groups to the ory of solids.

BIBLIOGRAPHY

I. Original Works. A complete bibliography is in Poggendorff, I, 283–284; III, 184–185; IV, 177. Bravais’s books include Thése d’astronomie sur les méthodes employées dans les levés sous voiles… (Paris, 1837); Über die geometrische Anordnung der Blätter und der Blüthenstände… (Breslau, 1839); Sur l’équilibre des corps flottants… (Paris, 1840); Le Mont Blanc (Paris, n.d. [1854]); and Études cristallographiques (Paris, 1866). He also contributed to many works or was a coauthor: “Étoiles,” in P. Leroux and J. Reynaud, eds., Encyclopédie nouvelle…, V (Paris, 1839), 100–109, also published separately as Lesétoiles Ou résumé d’astonomie stellaire (Paris, 1844); the notes for L.F. Kaemtz’s Cours complet de météorologie…, trans. and annotated by Charles Martins (Paris, 1843); the following volumes (as coauthor) of Voyages de laCommission scientifique du Nord… Météorologie, 3 vols. (1844–1855); Magnétisme terrestre, 3 vols. (1843–1850); Aurores boréales (1845); Géographie physique, gégraphie botanique, botanique et physiologie, 2 vols. (1844–1846); and Astronomie et hydrographie (n.d.); three letters in A. Quételet, Lettres à S.A.R. le duc régnanat de Saxe–Cobourg et Gotha, sur la théorie des probabilités… (Brussels, 1846), pp. 412–424; and two chapters in Patria. La France ancienne et moderne…, 2 vols. (Paris, 1847), 1, 1–142, 143–176.

Bravais’s papers appeared in many journals; the Annales des sciences naturelles, from 2nd ser., Botanique, 7 (1837) to 3rd ser., Botanique, 3 (1845); Comptes rendus hebdomadaires… de l’Académie des sciences, from 4 (1837) to 42 (1856); Mémoires présentés par divers savants…, 9 (1846); Nouveaux mémoires de l’Académie roylae des science et belles–lettres de Bruxelles, 14 (1841); Mémoires courpnnés… par léAcadémie royale… de Bruxelles, 15 , pt. 2 (1843); Annales de chimie et de physique, from 3rd ser., 5 (1842) to 3rd ser., 46 (1856); Journal de mathématiques pures ou appliquées… from 8 (1843) to 2nd ser., 1 (1856); Journal de l’École polytechnique, from 30th cahier, 18 (1845) to 34th cahier, 20 (1851); the reports of the 6th and 9th sessions of the Congrès scientifique de France (1839, 1842); the Bibliothèque universelle de genève (1845); Le moniteur universel (18 Sept. 1844); Revue Scientifique et industrielle, 2nd ser., 4 (Jan. 1845); and Annuaire météorologique de la France for the years 1849–1853.

His communications to the Société Philomathique are condensed in L’Institut; Ire section, Sciences mathématiques, physiques et naturelles between 15 Feb. 1837 and 29 Nov. 1854; they are reproduced, after correction of misprints, in Extaits des procés–verbaux… of the Society for the years 1837–1854.

Lithographed copies of Bravais’s courses are École Ploytechnique, 2nd div., “Cours de physique, Ire année d’étude 1847–1848” École Polytechnique, 1st div., “Cours de physique. 2e année 1848–1849”; École Impériale Polytechniques, 2nd div., “Sommaire du cours de physique, Ire année” (1853–1854); École Impériale Polytechnique, 1st div., “Sommaire du cours de physique. 2e année” (1854–1855).

II. Secondary Literature, Writing on Bravais or his work are J.–M.–J. Bouillat, “Auguste Bravais, Voyageur et savant (1811–1863),” in Les contemporains, no. 588 (Paris, 1904); Élie de Beaumont, Éloge historique d’Auguste Bravais (Paris, 1865), trans, in the Smithsonian Report for 1869, pp. 145–168; J. Fournet, “Rapport sur trois mémoires de Bravais,” in Annales des sciences physiques et naturelles…, 9 (1846), lxxi–lxxv; and Jean Messié, “Auguste Bravais, savant annonéen,” in Revue du Vivarais, 67 (Jan.–Mar. 1963). 7–11.

Charles Martins wrote several works concerning his work with Bravais: “Lettre sur le voyage aux terres arctiques,” in Revue médicale française et étrangére (1838), 4 433–438; “Observations sur les migrations et les moeurs des Lemmings,’ in Revue zoologique… (July 1840). 193–206; “Une ascension au Faulhorn,” in Revue médicale française et étrangère (1841), 4 209–214; “Un hivernage scientifique en Laponie,” in Revue indépendante (25 Dec. 1843), 483–511: “Ascension au Mont Blanc par MM. Martins, Bravais et Lepileur,” in L’illustration, journal universal (5 Oct. 1844), 68–74; “Deux ascensions scientifiques au Mont–Blanc…,” in Revue des deux mondes (15 Mar. 1865), 377–411; and Du Spitzberg au Sahara (Paris, 1866).

Archival materials are Bravais’s dossiers in the Service Historique de la Marine and in the Archives de l’Acdémie des Sciences; the Registre de matricule des éléves, V (1820–1830), 353, at the École Polytechnique, Secrétariat de la bibliothèque; and the archives of the Société Philomathique, cartons 123–134, at the Bibliothèque de la Sorbonee.

Also used in preparing this article were Distribution générale des prix aux élèves des collèges royaux de Paris et de Versailles for 1827 (p. 23 and for 1829 (p. 10; Auguste Bérard, Description nautique des côtes de l’ Algérie…(Paris, 1837); “Instruction pour l’expédition scientificque qui se rend dans le Nord de l’Europe,” in Comptes rendus de l’Académie des sciences, 6 (23 Apr. 1838), 526–571; (30 Apr. 1838), 585; (13 May 1838), 673; (21 May 1838), 704; Gabriel Delafosse, “Recherches sur la cristallisation, considérée sous les rapports physiques et mathématiques,” in Mémoires présentés par divers savants…, 8 (1843), 641–690, first presented int he comples rendus, 11 (31 Aug. 1840), 394–400, and reported by Beudant, ibid., 12 (25 Jan. 1841), 205–210, Abbé Filhol, Histoire religieuse et civile d’Annonay, IV (Annonay, 1882); Mémoiresde l’Acadèmie royale des sciences, belles–lettres et arts de Lyon. Section des lettres et arts, 1 (1845), 111; and Notice des travaux scientifiques de M.A. Bravais (Paris, 1851, 1854).

Arthur Birembaut