Dalencé, Joachim

(b. Paris, France, ca. 1640; d. Lille, France, 17 February 1707 [?])

astronomy, physics.

Few details are known of Dalencé’s life; most information is drawn from archival material and correspondence.

His father, Martin Dalencé, surgeon, to the king and a Jansenist, purchased for him the office of royal secretary and counsellor on 15 September 1663.

In 1668, during a trip to England, where he bought a telescope, Joachim formed a friendship with Henry Oldenburg, and in 1675 he is known to have served as an intermediary between Oldenburg and Huygens. He was also in communication with Leibniz and served as liaison between the French Academy and Huygens.

Beginning in 1679 he published anonymously the first six collections of the Connaisance des temps, the first French ephemerides of a purely scientific nature.

He gave up this project in 1684 and in 1685 moved to the Low Countries, where for three years he purchased books and art objects for the royal collections.

During this time he published the Traité de l’aiman (1687), a well–written discussion of magnets, and the Traittez des barometres, thermometres et notiometres ou hygrometres(1688).

His detailed description of the principal meteorological instruments of the period is enriched with several new ideas, such as the calibration of the thermometric scale on the basis of two points of change of state; the point at which water freezes and—a much more contestable point—that at which butter melts.

Dalencé married Geneviève Troisdames, by whom he had at least one son, Denis.

BIBLIOGRAPHY

I. Original Works. Dalencé’s writings include La connaissance des temps, ou calendrier et ephemerides du lever et du coucher de la lune et des autres planètes, avec les eclipses pour l’année (Paris, 1679–1684); Traité de l’aiman, 2 pts. (Amsterdam, 1687); and Traittez des barometres, thermometres et notiometres ou hygrometres (Amsterdam, 1688, 1708, 1724; Liège, 1691; The Hague, 1738).

II. Secondary Literature. For Dalencé’s life and work see A. Birembaut, “La contribution de Réaumar à la thermométrie,” in La vie et l’oeuvre de Réaumur (1683–1757) (Paris, 1962), p. 48; M. Daumas, Les instruments scientifuques au XVIIe et XVIIIe siècles (Paris, 1953), pp. 77–79; J. Guiffrey. Comptes des bâtiments du roi sous le règne de Louis XIV, Vols, II and III (Paris, 1887, 1891), passim; A. R. Hall and M. B. Hall, eds., The Correspondence of Henry Oldenburg, Vol. V (Madison, Wis., 1968), passim; C. Huygens, Oeuvres complètes, Correspondance, Vols. VII, IX (The Hague, 1897, 1901); E. Labrousse, Inventaire critique de la correspondance de Pierre Bayle (Paris, 1960), Passim; M. Marie, Histoire des sciences mathématiques et physiques, V (Paris, 1884), 130; W. E. R. Middleton, A History of the Thermometer (Baltimore, 1966); A Rivaud, Catalogue critique des manuscrits de Leibniz, 2nd cahier (Poitiers, 1914–1924), nos. 329, 1105; and the article on Dalancé in Nouvelle biographie générale, I (Paris, 1852), col. 786.

RenÉ Taton