Publisher Information: Utrecht: 1923.
Meitner, Lise (1878-1968). Autograph picture postcard signed, in German, to Otto Hahn (1879-1968). Utrecht, 14 September 1923 (postmarked the next day). 89 x 138 mm. One corner a bit bent, but very good. A fascinating postcard documenting not only the decades-long friendship and research collaboration between Meitner and Hahn, co-discoverers of nuclear fission, but also Meitner’s friendship with Einstein and the important Dutch physicist Paul Ehrenfest with whom she had been friends since her student days. The postcard reads as follows:
"L[ieber] O[tto] H[ahn], Ich bin eben von Leiden hierher gefahren u[nd] sitze im Bahn […], zum erstenmal ohne begleitenden Schutz. In Leiden hat mich noch Einst[ein] auf die Bahn gebracht, mit dem ich zwei wirklich schöne Tage in Ehrenfests Haus verbracht habe. Heute um 4h muss ich hier abfahren. Ich komme höchst wahrscheinlich Sonntag früh, am 16. abend muß ich noch in Eindhoven […], wohin ich morgen fahre. Ich hoffe Ihr seid alle wohl. Viele herzliche Grüße, Deine Lise M. Grüße auch die Institutsjugend."
[I have just traveled here from Leiden and am sitting in the railway station, for the first time without accompanying protection. In Leiden Einstein, with whom I spent two wonderful days in Ehrenfest’s house, escorted me to the train. I must leave from here at 4 o’clock. I will most probably return on Sunday morning; on the evening of the 16th I must [. . .] in Einthoven, where I am going tomorrow. I hope you are all well. Many hearty greetings, your Lise M. Greetings also to the Institute youth.]
Meinter wrote the postcard during her first visit to the Netherlands, a lecture tour arranged by her friend Dirk Coster, professor of physics at the University of Groningen. Coster would later play a critical role in Meitner’s life: In 1938 he persuaded her to leave Nazi Germany to avoid persecution as a Jew, and accompanied her during her the first leg of her escape, from Germany to the Netherlands.
Meitner obtained her doctorate in physics from the University of Vienna in 1905, where she became friends with her fellow student Paul Ehrenfest. In 1907 Max Planck invited her to Berlin to continue her post-doctoral studies; there she met radio-chemist Otto Hahn, who would be her research partner for the next thirty years, and also made the acquaintance of Einstein. During those early years in Berlin, before the outbreak of World War I, Einstein, Ehrenfest, Meitner and others would often gather at Planck’s home for long evenings of music and conversation.
In 1912 Hahn and Meitner joined the Kaiser Wilhelm Institute for Chemistry in Berlin (Meitner as an unpaid “guest” due to the fact that she was a woman), where they investigated the complex physical properties of radioactive elements and discovered the element protactinium (Pa). In 1919 Meitner was made a professor at the KWI, where she served as head of the Institute’s physics department, and in 1926 she was appointed full professor of physics at the University of Berlin—the first woman in Germany to hold such a post. Between 1924 and 1934 the Hahn-Meitner team gained international prestige with their work in what became known as nuclear physics. In 1934, after learning about the results of Fermi’s neutron bombardment of uranium, Meitner persuaded Hahn and his assistant, Fritz Strassmann, to join her in a thorough investigation of these phenomena. During the next four years (1934-38) the Meitner-Hahn-Strassmann team identified numerous radioactive “transuranes” resulting from neutron bombardment of uranium; although the chemical evidence for these elements appeared strong, the physics of their creation—which conformed to no known pattern—puzzled Meitner deeply. Meitner also had other problems to contend with—as a Jew in Nazi Germany, she found her career and even her life becoming steadily more endangered, and in July 1938, with the aid of Dirk Coster, she fled to safety in Stockholm. Although forced to abandon her hands-on investigations at the KWI, Meitner maintained a constant scientific correspondence with Hahn, and was thus kept abreast of their ongoing researches.
In 1938 Hahn and Strassmann, continuing with the irradiated uranium investigations, discovered barium isotopes among the decay products produced by the bombarded nuclei. At a loss to interpret this result, the two men communicated their result by letter to Meitner, who, with the help of her nephew Otto Frisch (a member of Bohr’s Copenhagen Institute for Theoretical Physics), came up with the correct explanation: The large uranium nucleus breaks up upon bombardment into two or more smaller nuclei through the mutual repulsion of its many protons, which makes it behave like a droplet of water in which the surface tension has been reduced. By taking the difference between the mass of the original nucleus and the slightly smaller total mass of the fragment nuclei, and using Einstein’s mass-energy equivalence, Meitner calculated the large amount of energy (equal to 200 million electron volts) that would be released during the splitting process, which she and Frisch named “fission.” Sime, Lise Meitner, p. 99.Book Id: 44102