BOUGUER

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 academie 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'academie des sciences_. in 1729 he published _essai d'optique sur la gradation de la lumiere_, 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 academie 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 determinee_. 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:--_traite d'optique sur la gradation de la lumiere_ (1729 and 1760); _entretiens sur la cause d'inclinaison des orbites des planetes_ (1734); _traite de navire, &c._ (1746, 4to); _la figure de la terre determinee, &c._ (1749), 4to; _nouveau traite de navigation, contenant la theorie et la pratique du pilotage_ (1753); _solution des principaux problemes sur la manoeuvre des vaisseaux_ (1757); _operations faites pour la verification du degre du meridien entre paris et amiens_, par mess. bouguer, camus, cassini et pingre(1757). see j.e. montucla, _histoire des mathematiques_ (1802).