Beschreibung:

BOUGUER, Pierre (1698-1758). La figure de la terre, dtermine par les observations de Messieurs Bouguer, & de la Condamine, de l'Acadmie Royale des Sciences, envoys par ordre du Roy au Prou, pour observer aux environs de l'quateur . Paris: chez Charles-Antoine-Jombert, 1749. 4 o (250 x 193 mm). With cancel leaves A1, N4, Y4 and Ll3, errata leaf at end. 8 folding engraved plates and one folding engraved map, woodcut title vignette by Papillon after nicolas-cochin-the-elder" title="Charles-Nicolas Cochin the elder">Charles-Nicolas Cochin 2 engraved headpieces, by Flipart l'ain after Cochin and after Soubeyran, woodcut factotum initials and tailpieces. (Occasional light browning.) Contemporary mottled calf, spine gilt, red-stained edges (rubbed). FIRST EDITION of the most important work to issue from the Peruvian expedition of 1735-1744, undertaken by the Academy with the encouragement of Maurepas with the goal of measuring an arc of the meridian near the equator, which resulted in the determination of the shape of the earth as an oblate spheroid. Bouguer quarreled with his fellow scientists on the expedition, La Condamine and Godin, and thus published his own report separately. "Bouguer's work on the expedition... was of high quality. Apart from the main geodetic program, he did an astonishing amount of other scientific work, measuring the dilatation of various solids by making use of the large range of temperatures found in the Cordillera, investigating the phenomena of atmospheric refraction and the measurement of heights with the barometer, devising a new type of ship's log, and undertaking a number of other researches, despite the very difficult physical conditions under which the geodetic measurements had to be carried out" (DSB). Alden & Landis 749/35; Sabin 6876; Norman 285. [ With :] BOUGUER, Pierre. Trait d'optique sur la gradation de la lumiere; ouvrage posthume . Paris: H. L. Gurin & L. F. Delatour, 1760. 4 o (268 x 210 mm). 7 folding plates, woodcut title vignette and tailpieces. UNCUT AND UNOPENED. (Occasional minor marginal dampstaining, final quire and folding plates detached.) Later 18th-century wrappers, manuscript title label on spine, pastedown endpapers from a late 18th-century almanac; cloth folding box. Provenance : E. N. da C. Andrade (bookplate, Sotheby's London, 7 February 1972, lot 29). FIRST EDITION of Bouguer's second and expanded work on photometry, completed just before his death and published by his friend the astronomer l'Abb Nicolas Louis de la Caille. "The Trait goes far beyond the Essai , describing a number of ingenious kinds of photometers ... and even attempting an elaborate theory of the reflection of light from rough surfaces, although this was not successful. The third and last part of the book, however, gives a valid elementary theory of the horizontal visual range through an obscuring atmosphere, arriving at a law, usually credited to H. Koschmieder, considered to belong to the twentieth century" (DSB). Norman 286. (2)