Lisle, Joseph Nicholas De

, younger brother of the preceding, was born at Paris April 4, 1688, and at first educated under his paternal roof. He then pursued his studies at the Mazarine-college, where the eclipse of the sun in 1706 seems to have directed his attention to astronomy, for which he soon displayed so much genius, as to be admitted into the academy of sciences, to the memoirs of which he contributed many valuable papers. In 1715 he calculated the tables of the moon according to the theory of sir Isaac Newton. He also, in the course of his pursuits, made many observations on the spots of the sun, and from them formed a theory to determine the sun’s rotation on his axis. In 1720 he delivered a proposal to the academy for ascertaining in France the figure of the earth, and some years afterwards this was carried into execution. In 1724 he paid a visit to England, where he became acquainted with Newton and Halley, who shewed him every mark of respect, and Halley in particular highly gratified | him by a present of a copy of his astronomical tables of the sun, moon, and planets, which he had printed in 1719, but which were not published for many years after. In. 1726 he was appointed astronomer royal in the imperial academy of sciences at Petersburg, where for twenty- one years he resided in the observatory-house built by Peter the Great, incessantly occupied in the improvement of astronomy and geography. During this period he published “Memoirs illustrative of the History of Astronomy,” 2 vols. 4to; and an atlas of Russia, first published in the Russian language, and afterwards in Latin. He constructed also a thermometer, differently graduated from those in use, the degrees beginning at the heat of boiling water, and thence increasing to 150, which was the freezing point. In 1747, after much ill-treatment on the part of the Russian government, he obtained his dismission, and arrived in Paris in September of the same year. He was then appointed professor of the mathematics at the college royal, in which situation he lived to render the greatest service to the interests of science, by training up some learned pupils, among whom was the celebrated M. de la Lande. In 1743, his pupil, M. Monnier, took a voyage to Scotland to observe an annular eclipse of the sun, and on this subject De Lisle published a large advertisement, which was reckoned a complete treatise on annular eclipses. He afterwards entered more fully on the consideration of the theory of eclipses, and he communicated a part of his researches on the subject to the academy in 1749. He was so expert in calculations, that he made many founded on the observations of Greenwich, Berlin, Scotland, and Sweden. In 1750 and 1753 he published “New charts of the Discoveries of admiral de Fonte, or Fuente, made in 1640, and those of other navigators, Spanish, Portuguese, English, Dutch, French, and Russian, in the Northern seas, with, explications.” In 1753 appeared his map of the world, in which he represented the effect of the parallaxes of Mercury in different countries, in order to point out the proper places for making such observations on the then expected transit, as should furnish a method of determining the distance of the sun, in a manner similar to that applied by Halley to the transit of Venus. Another work of his, published in the Transactions of the Academy, was on the comet of 1758, which was visible several months; but he was principally attentive to the one predicted by Di% Halley, | forty years before, which was first seen in January 1759, He gave an account of his observations on that comet irr the first volume of the “Mercure,” for July of that year. He was afterwards assiduously engaged on the transit of Venus, expected in 1761, in order to correct the error of Halley, and thus prevent persons from undertaking long voyages unnecessarily for the sake of observing it. He had, some years previously to this, been appointed astronomical geographer to the marine, and his business was to collect and arrange the plans and journals of naval captains, and to extract from them whatever might be found beneficial to the king’s service in this department. His majesty now purchased, with a pension- for life, all M. de Lisle’s rich astronomical and geographical collections, which were added to the Mss. in the depot. In 1758, JDeginning to decline, he withdrew as much as he could from public life, leaving the care of his observations to M. Messier, while M. de la Lamle was appointed his coadjutor at the college royal. He went to reside at the abbey of St. Genevieve, where he spent his time partly in devotional exercises, and partly in study, devoting the greatest part of his income to- acts of benevolence and charity. He died on the 11th of July 1768, in the eighty-first year of his age. As a man of science his merits are very great, and in private life he was distinguished by unaffected piety, pure morals, undeviating integrity, and most amiable manners. 1

1 Eloge by Lalande, io the Necrologie des Homines Celebres, for 1770. Rees’s Cyclopedia.