2 books for « becquerel edmond i... »Edit

‎Recherches sur divers Effets Lumineux qui résultent de l'Action de la Lumiere sur les Corps.(Ce Travail comprend les deux Mémoires présentés à l'Academie des Sciences le 16 novembre 1857 et le 24 Mai 1858). (Premiere-deuxieme Mémoire).‎

‎(Paris, Victor Masson et Fils, 1859). Without wrappers. In: ""Annales de Chimie et de Physique"", 3e Series - Tome 55, Cahier Janvier 1861. Pp. 5-128 a. 2 large folded engraved plates (emission-lines and the phosporoscope). The entire issue offered.‎

‎First appearance of Becquerel's first two pioneering studies on lluminiscent phenomena. ""It was in these studies that Becquerel first described the phosphoroscope, an instrument of his own invention consisting of a box sealed with two disks mounted on the same axis and pierced with holes arranged in such a way that light could not at any one time pass through the entire apparatus. By rapidly revolving these perforated disks, an observer could continously view substances in the dark only fractions of a second after they had been exposed to brilliant light"" and by regulating the speed of the revolution of the disks, one could measure the lenght of time that substances continued to glow after the exposure to light. Using this device, Becquerel was able to identify many new phosphorescent substances and to show that the phenomenon G.C. Stokes had named fluorescence in 1852 was in reality only phosphorescence of an extremely short duration....In this manner substances could be analyzed without physical or chemical alteration.""(DSB I, p. 556).Becquerel dis his most importent work in optics on the phenomena of luminescence. In the middle years of the nineteenth century, he virtually monopollized the significant discoveries made inthis field.(DSB).‎