Recherches sur le Spectre solaire et sur les Spectres des Corps Simples. Traduit de l'allemand, par M.L. Grandeau. (Premier-) Seconde Partie. (2 Papers).

Paris, Victor Masson et Fils, 1863 a. 1864. Boundin 2 contemp. hcalf. Gilt spines, raised bands, light wear along edges. In: "Annales de Chimie et de Physique", 3e Series - Tome 68 a. 4e Series, tome 1. 512 pp. a. 5 large folded engraved plates. + 512 pp. a. 3 large folded engraved plates. Kirchhoff's papers: pp. 5-45 a. pp. 396-411. 5 plates belongs to K's papers, 4 showing spectra and 1 plate (double page) depicts the famous spectroscope invented by K. and used by K. and Bunsen in their importent analysis of the spectra of the elements. First edition in French of Kirchhoff's milestone papers on the interpretation of the dark D lines - noticed by Fraunhofer in 1814 - in the spectrum of the sun, the papers that inspired Max Planck to his theory of quanta (1900). The papers are the French translations of his papers published in Abhandl. d. königl. Akad. d. Wissenscchaften in Berlin in 1861 and 1862.In the course of his preparatory work in the autumn of 1859, Kirchhoff made an unexpected observation. It had long been known that the dark D lines, noticed in the solar spectrum by Fraunhofer (1814), coincided with the yellow lines emitted by flames containing sodium.Kirchhoff's unexpected discovery was that if the intensity of the solar spectrum increased above a certain limit, the dark D lines were made much darker by the interrposition of the sodium flame. He instantly felt that he had got hold of "something fundamental", even though he was at a loss to suggest an explanation. On the day following the surprising observation, Kirchhoff found the the correct interpretation, which wass soon confirmed by new experiments: a substance capable of emittiing a certain spectral line has a strong absorptive power for the same line.The dark D lines in the solar spectrum could accordingly be ascribed to absorption by a solar atmosphere containing sodium. Immense prospects thus opened up of ascertaining the chemical composition of the sun and other stars from the study of their optical spectra. A few more weeks sufficed for Kirchhoff to elaborate a quantitative theory of the relationship between emissive and absorptive poweer."(DSB VII, pp. 381-82).PMM, 278 b. - Barchas, 1169-70 - Sparrow, 117 - Horbli, 59 - Dibner, 153 (the note).…