Eberhard Buchwald. Das Korrespondenz-prinzip. Sammlung Vieweg, Heft 67. Fr. Vieweg-Verlag, Braunschweig, 1923, pp. VI + 127.

Eberhard Buchwald. The Correspondence Principle.

In modern teaching about the structure of the atom, the correspondence principle occupies a central place. It proves to be indispensable both in the study of the simplest hydrogen atom, and, for example, for a complete description of the phenomena of Stark and Zeeman. With its aid we can pass to the construction of a theory of more complex atomic and molecular systems, despite our insufficient knowledge of the mechanical and electrodynamic laws governing them. However, acquaintance with this fruitful principle is greatly hampered by the circumstance that there is still no systematic and detailed exposition of it. Everything relating to it is scattered in the form of journal articles—chiefly by Bohr himself and his pupils—as well as in Bohr’s books Three Articles on Spectra and the Structure of Atoms and Über die Quantentheorie der Linienspektren and the dissertations of Kramers and Burgers. Therefore the appearance of Buchwald’s book will be welcomed by many. In 130 pages, very elementary and clear, the author sets forth the most important applications of the correspondence principle, analyzing in detail a number of the most important cases. The exposition is almost everywhere conducted so thoroughly that it does not require the reader to have prior knowledge. Only the small size of the book did not allow a more detailed treatment of the theory of complex atoms, in particular Bohr’s ideas on the formation of the periodic system by the successive capture of electrons. In any case, the book will greatly facilitate the study of the theory of the atom.

Gr. Landsberg.