Bouguer, Pierre(pyĕr bo͞ogĕr`), 1698–1758, French mathematician and hydrographer. He made some of the first photometric measurements, calculating the intensity of the light of the sun as compared with that of the moon, and invented (1748) the heliometer. His works include Essai d'optique sur la gradation de la lumière (1729) and La Figure de la terre (1749).
Born Feb. 16, 1698, in Le Croisic, Brittany; died Aug. 15, 1758, in Paris. French physicist; one of the founders of photometry. Member of the Paris Academy of Sciences (1731).
At age 15, after his father’s death, Bouguer replaced him in his duties as a professor of hydrography. Bouguer was the first to establish the concept of a quantity of light, formulate the basic position of visual photometry (the principle of light gradation), describe photometric instruments, and work out methods of measuring the brightness of light. In 1729 he established the law of the weakening of a light ray in an absorbing medium. He was the author of Treatise About the Ship (1746) and A New Work on Navigation, Containing the Theory and Practice of the Navigational Art (1753), which were of great importance in the development of ships and shipping. From 1735 to 1743, along with C. M. de la Condamine, Bouguer headed an expedition organized by the Paris Academy of Sciences, which carried out grade measurements in Peru with the goal of defining the earth’s shape.
WORKSIn Russian translation:
Opticheskii traktat o gradatsii sveta. Moscow-Leningrad, 1950. (With a bibliography of Bouguer’s works.)