Künstliche Atomumwandlungen und die Spaltung schwerer Kerne; reprinted from Strahlentherapie, 75. Band, 1944, pp. 16–27

Berlin and Vienna: Urban & Schwarzenberg, 1944. First Edition. Offprint, 8vo (241 × 171mm), pp. 12. Sonderabdruck from the journal of the Deutsche Röntgengesellschaft and the Deutsche Gesellschaft für Lichtforschung. Self-wrappers, staple-bound, soft crease, light toning, publisher's paper reinforcement to the spine with some staple rust, else near fine. Signed by Hahn on the front wrapper. A survey lecture delivered at Bremen on October 21, 1940 and at Jena on June 25, 1942, in which Hahn, as director of the Kaiser-Wilhelm-Institut für Chemie in Berlin-Dahlem, reviews the state of artificial nuclear transmutation and heavy nucleus fission for a medical-scientific audience. The paper covers the principal modes of artificial atomic transformation (alpha-particle bombardment, proton and neutron irradiation, and beta-decay chains) and their products, including artificially radioactive isotopes and their applications as tracers and indicators in chemistry and biology. The second half addresses nuclear fission directly, summarizing the experimental evidence for the splitting of uranium and thorium nuclei under neutron bombardment, the range of fission products identified across the periodic table, and the role of secondary neutrons in sustaining the chain reaction. Written and delivered before the public announcement of the atomic bomb, the paper reflects Hahn's position at the center of the discovery he had made with Strassmann in December 1938, presenting its implications within the framework of academic science while the military applications of that same discovery were being pursued elsewhere.