Henrion, Denis or Didier

(b. ca 1580; d. Paris [?], France, ca. 1632)

mathematics.

Information on Henrion is very scarce and imprecise. The date and place of his birth are unknown. In 1613 he speaks of his youth; and since he had been an engineer in the army of the prince of Orange before settling in Paris in 1607, his birth may be placed around 1580. The date of his death is somewhat delimited by the appearance in 1632 of the French edition of Euclid’s Elements and Data, under his name, sold “en l’Isle du Palais, à l’lmage S. Michel, par la veusve [widow] dudit Henrion.” His first name is generally indicated as Denis, although he always gave only the initial D.—except in a Latin writing of 1623, where it is given as Desiderius, the Latin form of Désiré or Didier.

Henrion’s scientific activity was devoted mainly to private instruction and to the translation into French of Latin mathematical texts. From 1607 it seems to have taken place exclusively in Paris. His first work, published in 1613, is a course in elementary mathematics, in French, for the use of the nobility, that is, for the instruction of officers. Although it displays no great originality, it is a serious work, most particularly the section on geometry, which contains a group of 140 remarkable problems. Yet here, as in all of his work, Henrion drew very freely on his predecessors, especially Clavius.

Henrion’s various editions of Euclid’s Elements were really only translations of the Latin editions done by the Jesuits at Rome. He sometimes embellished them with a summary of the algebra in which this science was presented in a quite antiquated manner, without regard for the advances made by Viète, Albert Girard, and Stevin.

When the Data was combined with this translation of Euclid in 1632, Henrion translated the introduction by Marinus of Flavia Neapolis and the text itself from the Latin of Claude Hardy (1625). His French translation of Theodosius of Tripoli’s Spherics (1615) was drawn from the Latin paraphrase by Clavius (1586).

Henrion’s other works are in the same vein. His Tradé des logaritlhmes (1626), taken from the work of Briggs, saved his name from oblivion by being the second work on the subject published in France—the first was that of Wingate (1625)—and the first written by a Frenchman.

Henrion was greatly interested in mathematical instruments, especially in the proportional divider, the invention of which he attributed to Jacques Alleaume, who had constructed several copies of it in Paris. He also described the slide rules of Edmund Gunter in the Logocanon (1626).

His work was not untouched by polemic. Henrion often bore a grudge against his competitors, the other translators of Euclid and writers of manuals. He was severely taken to task by Claude Mydorge regarding his notes to Jean Leurechon’s Recréations mathématiques.

In conclusion, the body of Henrion’s work, although greatly inferior to that of Hérigone, nevertheless played a not unimportant initiatory role in France.

BIBLIOGRAPHY

Henrion’s own writings include Mémoires mathématiques recueillis et dressez en faveur de la noblesse françcoise, 2 vols. (Paris, 1613–1627; 2nd ed., vol, I, 1623); Traicté des triangles sphériques (Paris, 1617); L’usage du compas de proportion(Paris, 1618; 2nd ed., Paris. 1624; 4; b ed.. Park 1631: 5th ed. Rouen, 1637, 1664, 1680), further eds. by Deshayes (Paris, 1682, 1685); Cosmographie ou traictée général des chases tant célestes qu’élémentaires (Paris, 1620; 2nd ed., Paris, 1626); Canon manuel des sinus, touchantes et coupantes (Paris, 1623); Somntaire de l’algébre trés nécessaire pour faciliter l’inierpréiation du dixiesme livre d’Euclide (Paris, 1623), which also appears in Henrion’s various eds. of Euclid; Sinuum, tangentium et secantium canon manualis (Paris, 1623); Logocanon, ou Regle proportionelle sur laquelle sont appliquées plusieun lignes et figures divisées seion diverses proportions et mesures (Paris, 1626); Traict’ des logarithmes (Paris, 1626); L’usage du mecometre, qui est un instrument géométrique avec lequel on peat trés facilement mesurer toutes sortes de longueurs (Paris, 1630); and Cours math’ématique demontré d’une nouvelle méthods (Paris, 1634).

Henrion edited or translated Les trois livres des Éléments sphériques de Théodnse Tripolitain (Paris, 1615); Les quinze livres des Élémens d’Euclide (Paris, 1614. 1615; 2nd ed., Paris, 1621; 3rd ed., Paris. 1623; 4III ed. Pans. 16.51: 5th ed,. Rouen. 1649): Traduction et annotations du Traicté des globes et de leur usage, de Robert Hues (Paris, 1618); Edtion dc la Geometric et practique générate d’icelle de Jean Errard (Paris, 1619); Les tables des directions et profections de Jean de Montroyal, corrigées, augmentées. et leur usage... (Paris, 1625; annotated new ed., Paris. 1626): Nottes sur les Récréations mathématiques du Fire Jean Lenrechon (Paris, 1627. 1630. 1639, 1659, 1660, 1669); and Les quinze livres des Élémens gémnétriques... plus le livre des Donnez du mesme Euclide... (Paris, 1632; Rouen, 1676; Paris, 1677, 1683; Rouen, 1683, 1685).

Jean Itard