THE DISCOVERY OF BALMER LINES.

BALMER, J. J. (JOHANN JAKOB).

Notiz über die Spectrallinien des Wasserstoffs.

Leipzig, Johann Ambrosius Barth, 1885. 8vo. Contemporary half calf. 5 raised bands, gilt spine and gilt lettering to spine. A few scratches to spine. Small stamp on half title, title page and verso of title page. In: "Annalen der Physik und Chemie", Band. XXV. VIII, 680 pp. + 4 large folded plates all with a small stamp.Balmer's paper: pp. 80-87. Internally fine and clean.

First edition of Balmer's seminal paper on spectral lines of the hydrogen atom which today is known as Balmer series, the first discovery of a mathematical relationsship between the frequencies of atomic spectral lines. Balmer's discovery was the decisive factor in Bohr's famous and groundbreaking discovery and description of his model of atomic structure published in 1913. "As soon as I saw Balmer's formula, the whole thing was immediately clear to me" Bohr told Leon Rosenfeld in an interview. (Heilbron, Historical studies in the theory of atomic structure, p. 265).

The discovery that sets of lines in the spectra of alkalis and alkaline earth are related in series was discovered by G. D. Liveing in 1879 but Balmer discovered a simple formula (presented in the present paper) how to relate the wavelength of a series of line in the visible spectrum of hydrogen. The Balmer series was far from similar to the more simple ratio proposed by George Stoney. Although Balmers fomular linked together the four then known hydrogen spectra and turned out to by applicable for the ultraviolet and infrared spectra of hydrogen a complete understandig of the relations came first with Bohr in 1913.

"What Balmer did is slightly incredible. Having at his disposal four frequencies measured by Åndgtröm, he fitted them with a mathematical expression that predicts an infinity of lines - and his formula is in fact correct! Balmer's formula has stood the test of time as more hydrogen lines kept being discovered. Soon his results became widely known; they were quoted in the 1912 edition of the Encyclopedia Britannica. For nearly thirty years no one knew, however, what the formula was trying to say - then Bohr came along." (Pais. Niels Bohr's Times, pp. 142-3).

Due to the relatively large occurrences of hydrogen in the universe the Balmer lines are useful in astronomy since the spectral classification of stars, which is primarily a determination of surface temperature, is based on the relative strength of spectral lines.
(Appeared simultaneously in Verhandlungen der Naturforschenden Gesellschaft in Basel, Vol. 7, 1885, pp. 548-556, 750-752).

Other papers of interest contained in the present volume:
Lorenz, L. Bestimmung der electrischen Widerstände von Quecksilbersäulen in absolutem electromagnetischen Maasse. Pp. 1-31.
Kirchhoff, G. Ueber einige Anwendungen der Theorie der Formänderung, welche ein Körper erfährt, wenn er magnetisch oder diëlectrisch polarisirt wird. Pp. 601-617.
And many other.

Order-nr.: 43112