‎"FRAUNHOFER, JOSEPH.‎
‎Kurzer Bericht von den Resultanten neuerer Versuche über die Gesetze des Lichtes, und die Theorie derselben. - [SPECTROSCOPY AND THE FORMULATION OF THE GRATING EQUATION]‎

‎(Leipzig), 1823. Wrappers blank. Uncut. Extracted from ""Gilberts Annalen der Physik und der Physikalischen Chemie"", Bd. 74, Jahrg. 1823, Achtes Stück, pp. (337-) 378. First and last leaves a bit browned.‎

Reference : 39978

‎First edition of this important paper where Fraunhofer analyzed diffraction phenomena and interpreted them in terms of a wave theory of light, leading him to formulate the GRATING EQUATION: ""In the paper in 1823, Fraunhofer revealed his continued invstigation of diffraction gratings. Using a diamond point, he could rule up to 3,200 lines per Paris inch. He continued his study of the effect of oblique rays, developed formulations based on the wave conception, and calculated a revised set of wavelenghts for the major spectral lines. Thus, his earlier observations of the dark lines in the solar spectrum enabled him to make the highly precise measurements of dispersions"" then his use of the wave theory of light allowed him to derive, with suitable simplifications, the general formulation of the grating equation still in use today."" (Reese V. Jenkins in DSB).‎