Braunschweig, Friedrich Vierweg & Sohn; Berlin, J. Springer, 1924. 8vo (23.0 x 15.6 cm). 17 pp.; one illustration. Original printed wrappers.

Seminal work by Werner Heisenberg on understanding the anomalous Zeeman Effect. “Heisenberg’s real talents emerged in his work on the anomalous Zeeman effect, in which atomic spectral lines are split into multiple components under the influence of a magnetic field. Heisenberg developed a model that accounted for this phenomenon, though at the cost of introducing half-integer quantum numbers, a notion at odds with Bohr’s theory as understood to date” ( Brittanica). Contained in: Zeitschrift für Physik, volume 26 (4-5), pp. 291-307. The complete issue, in its original wrappers. Slight marginal fraying; both lower corners with a small bump; and minimal spotting at wrapper top edge; small chip and tear to spine top; otherwise a very good, clean and unmarked copy. Werner Heisenberg, in: Brittanica online. See also Mehra and Rechenberg (1982) The Discovery of Quantum Mechanics, pp. 10-126.