(b. Le Mans, France, ca. 1598; d. Paris, France, 5 April 1678)
Little is known about Hardy’s life. He is said to have been born in 1598 (G. Loria) or in 1605 (Claude Irson). In 1625 he was a lawyer attached to the court of Paris and in 1626 a counselor in the Châtelet. He took part in the weekly meetings of Roberval, Mersenne, and the other French geometricians in the Académie Mersenne, and was a friend of Claude Mydorge, who introduced him to Descartes. Several writers of the seventeenth century suggested methods for the duplication of the cube, including Viéte, Descartes, Fermat, and Newton. Among the less well-known persons who also occupied themselves with this problem was Paul Yvon, lord of Laleu, who claimed that he had found the construction of the two mean proportionals, required in solving the problem. In addition to Mydorge and J. de Beaugrand, Hardy exposed the fallacy of Yvon’s construction in his Examen of 1630 and again in his Refutation of 1638. In turn Hardy was attacked by other scholars. Owing to a lack of explicitness in statement, Fermat’s method of maxima and minima and of tangents was severely attacked by Descartes. In the ensuing dispute Fermat found two zealous defenders in Roberval and Pascal, while Mydorge, Desargues, and Hardy supported Descartes.
Hardy owed his greatest fame, however, to his knowledge of Arabic and other exotic languages, and in particular, to his edition of Euclid’s Data (1625), the editio princeps of the Greek text, together with a Latin translation. He is said to have translated the Isagoge (Tours, 1591) and the Zetetica (Tours, 1593) of Viète and to have occupied himself with a project for a universal language.
I. Original Works. Hardy’s ed. of the Data was published as Euclidis Data. Opus ad ueterum gemetriae autorumArchimedis, Apollonii, Pappi, Eutocii ceterorumque...(Paris, 1625). He was author of Examen de la duplication du cube et quadrature du cercle, cy-devant publiée à diverses fois par le Sieur de Laleu... (Paris, 1630); and Refutation de la manière de trouver un quarré égal au cercle rapportée ès pages 130 et 131 du livre nouvellement imprimé sous le titre de Propositions mathématiques de Monsieur de Laleu demonstrées par I. Pujos, et au prétendu triangle équilatéral mentionné au placard dudit sieur... (Paris, 1638).
II. Secondary Literature. On Hardy and his work, see (listed in chronological order) P. Colomiès, Gallia orientalis (The Hague, 1665), pp. 165–166, 259–260; C. Irson, Nouvelle méthode pour apprendre facilement les principes et la pureté de la langue françoise (Paris, 1667), p. 317; G. Loria, Storia delle matematiche, II (Milan, 1931), 309; and C. de Waard, ed., Correspondance du M. Mersenne, I (Paris, 1932), 187, 619, 666; II (Paris, 1937), 116, 550, 551; III (Paris, 1946), 230; IV (Paris, 1955), 322, 323; V (Paris, 1959), 136; VII (Paris, 1962), 63, 288–292; VIII (Paris, 1963), 417, 418.
H. L. L. Busard