. See Argonne.

D'Arquier (Augustine), a French astronomer, fellow of the royal society of Toulouse, correspondent member of the royal academy of Paris, and a member of the Institute, was born at Toulouse, Nov. 23, 1718, and having early cultivated the science of astronomy, and the sciences connected with it, devoted his long life to the same pursuits, and acquired great reputation among his countrymen. Such was his enthusiasm, that, without any assistance from government, he purchased the most valuable instruments, erected an observatory on his house, taught scholars, and defrayed the expence of calculations, &c. He died in his native city, Jan. 18, 1802. He published, 1. “Observations Astronomiques faites a Toulouse, &c.Paris, 1778, 4to, the most complete collection of observations that had ever been furnished from a provincial city. There are six hundred of the moon, thirtythree oppositions, several observations of Mercury, of the spots in the sun, the satellites of Jupiter, and the eclipses of the stars. One of the most surprizing circumstances in this collection is the great number of the passages of Mercury that have been observed by M. D’Arquier, | notwithstanding the pretended difficulties which have discouraged modern astronomers from observing that planet. 2. “Observations Astronomiques,” 17s3, 2 vols. 4to, containing a series of the usual astronomical observations, from 1748 to 1781: some useful instructions on the management of the pendulum: and observations on the motion and magnitude of the Georgium sidus. 3. “Lettres sur l’astronome pratique,1786, 8vo. Besides these he published some translations, as Simson’s Geometry, Lambert’s Cosmological Letters, and Ulloa’s Observation on the eclipse of the sun in 1778. D’Arquier died Jan. 18, 1802, in Toulouse. 1


Dict. Hist. Month. Kev. vols. LIX and LXX.