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).

BOUGUEREAU, ADOLPHE WILLIAM (1825-1905), French painter, was born at La
Rochelle on the 30th of November 1825. From 1843 till 1850 he went
through the course of training at the Ecole des Beaux-Arts, and in 1850
divided the Grand Prix de Rome scholarship with Baudry, the subject set
being "Zenobia on the banks of the Araxes." On his return from Rome in
1855 he was employed in decorating several ar