LE MONNIER, PIERRE CHARLES, b. France; son of Pierre Le Moonier, a French astronomer and professor of philosophy in the college d'Harcourt; having inherited a love for the study of astronomy, and having proved his aptitude by drawing a correct map of the moon, which he presented to the academy of sciences, was elected a member of that society, as adjunct geometrician, and in the following year was asso ciated with Maupertuis and.Clairaut, at Tornea, in measuring a degree of the meridian ia Lapland, within the polar circle. He favored the introduction of the methods of Flamsteed, and the superior astronomical instruments of the English. In 1742, by the bounty of the king. to whom lie was introduced by the due de Noailles. he occupied apartments at the Capueins, rue St. Honors, and held them till the revolution; he also received a royal present of 15,000 livres, in acknowledgment of his services in fixing an accurate meridian at St. Sulpice. From 1732 to 1741 he was engaged in determining the sun's greatest equation, which in the latter year lie found amounted to 1° 55' 31'. In 1739 he was elected honorary member of the royal society of London, and for 12 years was its senior member. In 1741 lie published llistoire Celeste. In 1746 and 1748 he
made some successful telescopic observations in relation to the planets Jupiter and Saturn. and an eclipse of the sun. He held the chair of professor of physics in the col lege of France for many years. In 1746 he published Institutions Afdronomiques, an elementary work. In 1748 he went to England, and thence to Aberdour, in Fifeshire. Scotland, with the earl of Morton to observe the solar eclipse. In 1771 he published Nautical Astronomy, and various treatises on navigation, magnetism, and the variations of the compass, etc. For 50 years his contributions appeared in successive annual pub lications of the memoirs of the academy. The celebrated Lalande was his pupil. From the year 1791 to his death lie suffered from the effects of a paralytic attack. He was one of the 144 original members of the national institute. In 1763 lie married Mlle. de Cussy of Normandy, and had three daughters, all of whom married, and the second became the celebrated Lagrange. He was buried at Aerie, near Bayeux.