Leipzig, Johann Ambrosius Barth, 1921. 8vo (21.5 x 14.1 cm). 28 pp., six text illustrations. Contemporary half morocco over marbled boards. Spine with blind embossing, gilt title and vignettes. Floral endpapers. Speckled edges.

Seminal paper by the physicist Carl Wilhelm Ramsauer (1879-1955) in which he described the discovery of what was to be named the Ramsauer–Townsend effect. "He pioneered the field of electron and proton collisions with gas molecules (Wikipedia). Ramsauer studied the absorption in gases of electrons with steadily decreasing velocity. On this occasion Ramsauer coined the term - and the associated concept - 'effective cross section' (Wirkungsquerschnitt), which became one of the most common technical terms in atomic and nuclear physics" (DSB). Contained in Annalen der Physik, fourth series, volume 64, edited by Wilhelm Wien and Max Planck. The whole volume. A clean copy, nicely bound and without any library marking. Light shelf wear to edges, otherwise a very good, clean copy. DSB 15, p. 490.