Über das Zerplatzen des Urankernes durch langsame Neutronen Abhandlungen der Preußischen Akademie der Wissenschaften. Jahrgang 1939. Mathematisch-naturwissenschaftliche Klasse.

Berlin: Akademie der Wissenschaften, 1939. Quarto. 20-page offprint, original green wrappers printed in black. A little fading along the spine and edges, lightly rubbed at the extremities. An excellent copy. The Abhandlungen offprint of the first of Hahn and Strassman's "three fundamental papers on nuclear fission, containing the first comprehensive account of the phenomenon" (Hook & Norman, Norman Library of Science and Medicine 963). Abhandlungen issues in the green wrappers are not true offprints because they could contain multiple papers, though in the case of the Hahn & Strassman fission papers each contains only the one paper. Offprints in the orange wrappers labelled "Einzelausgabe" are the true offprints, as they only ever contained a single paper. "In 1938 Hahn and Strassman had demonstrated the presence of radioactive barium, lanthanum and cerium among the products of neutron bombardment of uranium, an observation that seemed to contradict all previous experiences of nuclear physics" (Hook & Norman). They announced these unexplained findings in an earlier paper published in Naturwissenschaften on January 6th, 1939, but before that wrote to Lise Meitner, then in exile in Copenhagen, "telling her of their baffling discovery and asking for advice. It was this letter that inspired Meitner and her nephew Otto Frisch to create their hypothesis of a fission process, which they published on 11 February 1939" (Hook & Norman). The present paper was presented at the May 25th, 1939 meeting of the Akademie and published on September 18th of that year. The following two papers in this series would not appear until 1944 and 1945.