Braunschweig, Germany: Friedr. Vieweg & Son, 1920. Hardcover. First Edition. iv, 478 pp. 8vo. Gray cloth spine with gray patterned cloth covers. Some scuffing overall with a clean interior. Previous owner's name in ink on first free endpaper.
Niels Bohr (1884-1962) first gives a name to the correspondence principle (“Korrespondenzprincip”) in a presentation to the Berlin Physical Society in 1920. The correspondence principle "says that for large orbits and for large energies, quantum calculations must agree with classical calculations." (https://en.wikipedia.org/wiki/Correspondence_principle) Also contains Otto Stern's article, “Eine direkte messung der thermischen molekulargeshwinidigkeit” (“Direct measurement for the thermal molecular velocity”) on pp. 49-56. Very Good. More

Berlin, Germany: Julius Springer, 1926. Hardcover. First Edition. viii, 948 pp, 8vo. Volume is ex-library with brown patterned paper boards, lighter brown cloth spines and corner tips; gold embossed titling to spine. Wear to edges of cover boards where cloth has worn to reveal board beneath, hinge cloth beginning to split at front and rear cover but still tight to boards. Library stamps within, including stamps on title page of each volume, very clean with card pocket remaining on the rear pastedown of each volume. All text in German.
“Über die Spektra von Atomsystemen mit zwei Elektronen” by Werner Heisenberg (pp. 499-518) outlines the experiment in which Heisenberg refined the principle of "exchange interaction" Very Good. More

Berlin, Germany: Julius Springer, 1926. Hardcover. First Edition. vii, 951 pp, 8vo. Volume is ex-library with brown patterned paper boards, lighter brown cloth spines and corner tips; gold embossed titling to spine. Library stamps within, including stamps on title page of each volume, very clean with card pocket remaining on the rear pastedown of each volume. All text in German.
“Über dass Wasserstoffspektrum vom Standpunkt der neuen Quantenmechanik” by Wolfgang Pauli (pp. 336-363) in which Pauli outlines his theory of the hydrogen spectrum which contributed to the study of quantum mechanics; “Zur Deutung einiger Erscheinungen in den Molekelspektren” by Freidrich Hund (pp. 657-674) is his early paper on Molecular Orbital Theory; “Zur Quantelung des Idealen Einatomigen Gases” by Enrico Fermi (pp. 902-912) outlines what became..... More

Darmstadt, Germany: Wissenschaftliche Buchgesellschaft, 1959. Hardcover. First Edition. First Wissenschaftliche Buchgesellschaft Edition, reprinting Riemann's 24, [2] Index pp. 12mo. Light terracotta cloth coverd boards with gold titling to spine. Clean, crisp copy with previous owner's signature in ink on first free endpaper. Text in German.
Translates to "On The Hypothesis Which Underlies Geometry" and originally delivered by Riemann in 1854. Riemann's work on "Riemann Geometry" was later used by Albert Einstein in the development of his theories. Fine. More