"Notiz uber die Spectrallinien des Wasserstoffs." In: Annalen der Physik und Chemie, Neue Folge, Band XXV, 1885.

Leipzig:: Johann Ambrosius Barth, 1885., 1885. 8vo. Pages 80-87. [Entire volume: viii, 680 pp.] Table. Quarter black cloth, cloth tips, paste-paper over boards, gilt spine; rubbed, inner hinge cracked. Ex library ms. spine label, rubber stamps. Very good. FIRST EDITION. Balmer was the first to discover a mathematical relationship between the frequencies of atomic spectral lines. "As soon as I saw Balmer's formula the whole thing was immediately clear to me," Niels Bohr remarked to Leon Rosenfeld (see: Hermann, Fruhgeschichte der Quantentheorie, pp. 173 ff.). (truncated) At the beginning the nineteenth century it had been found that the wavelength of the light emitted by some elementary substances when heated in a flame were characteristic of the atom involved. It became clear from the work of Fraunhofer, Bunsen and Kirchhoff that all the chemical elements could be identified by unique but complicated line spectra. At first these were merely tabulated, for their complexity baffled any attempt to see order in them. The first sign of this order was found in 1885 by the Swiss privatdozent Johann Balmer. Balmer made his great discovery without having received any specialized training in physics, and when he was almost sixty years of age. In 1884 he announced to the Basle Natural Science Society his finding that the frequencies of the lines in the hydrogen spectrum form a convergent series, now called the Balmer Series in his honor. (Appeared simultaneously in Verhandlungen der Naturforschenden Gesellschaft in Basel, Vol. 7, 1885, pp. 548-556, 750-752). Cajori, A history of physics, pp. 336-339; DSB, I, p. 425; Magie, A source book in physics, pp. 360-365; Pais, Inward Bound, pp. 170-173; Schonland, The atomists, pp. 65 ff. (Inventory #: S6021)