1911 Encyclopædia Britannica/Bouguer, Pierre

BOUGUER, PIERRE (1698–1758), French mathematician, was born on the 16th of February 1698. His father, John Bouguer, one of the best hydrographers of his time, was regius professor of hydrography at Croisic in lower Brittany, and author of a treatise on navigation. In 1713 he was appointed to succeed his father as professor of hydrography. In 1727 he gained the prize given by the Académie des Sciences for his paper “On the best manner of forming and distributing the masts of ships”; and two other prizes, one for his dissertation “On the best method of observing the altitude of stars at sea,” the other for his paper “On the best method of observing the variation of the compass at sea.” These were published in the Prix de l’Académie des Sciences. In 1729 he published Essai d’optique sur la gradation de la lumière, the object of which is to define the quantity of light lost by passing through a given extent of the atmosphere. He found the light of the sun to be 300 times more intense than that of the moon, and thus made some of the earliest measurements in photometry. In 1730 he was made professor of hydrography at Havre, and succeeded P. L. M. de Maupertuis as associate geometer of the Académie des Sciences. He also invented a heliometer, afterwards perfected by Fraunhofer. He was afterwards promoted in the Academy to the place of Maupertuis, and went to reside in Paris. In 1735 Bouguer sailed with C. M. de la Condamine for Peru, in order to measure a degree of the meridian near the equator. Ten years were spent in this operation, a full account of which was published by Bouguer in 1749, Figure de la terre déterminée. His later writings were nearly all upon the theory of navigation. He died on the 15th of August 1758.

The following is a list of his principal works:—Traité d’optique sur la gradation de la lumière (1729 and 1760); Entretiens sur la cause d’inclinaison des orbites des planètes (1734); Traité de navire, &c. (1746, 4to); La Figure de la terre déterminée, &c. (1749), 4to; Nouveau traité de navigation, contenant la théorie et la pratique du pilotage (1753); Solution des principaux problèmes sur la manœuvre des vaisseaux (1757); Opérations faites pour la vérification du degré du méridien entre Paris et Amiens, par Mess. Bouguer, Camus, Cassini et Pingré (1757).

See J. E. Montucla, Histoire des mathématiques (1802).