Essai d'optique sur la gradation de la lumiere.

12mo: [22]-164-[4] pp.; 3 pl. (sl. age-toned).

Contemp. mottled calf, gilt-orn. spine with raised bands, gilt sides, inner dentelles and edges (corners, sides, joints, bands and head sl. rubbed).

First edition by the French mathematician, geophysicist, geodesist and astronomer P. Bouguer (1698-1758), discoverer of the first practical way to measure light. "Bouguer’s achievement was to see that the eye could be used, not as a meter but as a null indicator, i.e., to establish the equality of brightness of two adjacent surfaces. He then made use of the law of inverse squares, first clearly set forth by Kepler." In this work he showed how to compare lights in this way and how to deal with the transmission of light through partly transparent substances. In the second part of "Essai optique" Bouguer deals with another of his discoveries often referred to as the Bouguer's law. This law was taken up by J.H. Lambert in his "Photometria" and, due to great rarity of copies of Bouguer's "Essai" sometimes unjustifiably referred to as Lambert's law. Ill. with 3 engr. fold. pl.
Ref. BnF. - DSB II:343.
Prov. Armorial bookpl. on front pastedown. - P. Lanszweert, Pharma, Ostend (bookpl. on lower bl. margin p. 77).
Joined: Leiss, C. - Die optischen Instrumente der Firma R. Fuess, deren Beschreibung, Justierung und Anwendung. Leipzig, Engelmann, 1899. 8vo. Bound (def., bookblock loose). Prov. Jean Mosselmans (bookpl.). - Stamp (on title). (2 vol.)