A study in the history of diffusion of knowledge: Part 7
Niels Bohr visiting Otto Hahn in 1920 in Berlin. From left to right: Otto Stern*, Wilhelm Lenz, James Franck*, Rudolf Ladenburg, Paul Knipping, Niels Bohr*, E. Wagner, Otto von Bayer, Otto Hahn*, Lise Meitner, Georg von Hevesy*, Wilhelm Westphal, Hans Geiger, Gustav Hertz*, Peter Pringsheim.
*Received Nobel Prizes; names in italics were forced to leave Germany or German-occupied countries; G. Hertz was forced to leave his job but did not leave Germany.
Turmoil in Europe and the migration of scientists
In 1933, the Nazis secured complete power in Germany and began to use it for the realization of their social and political aims. They launched the most formidable armaments program ever attempted up to that time. Among their aims were the extermination of the Jews and the domination of the world as the “master-race,” believing that they possessed some quality that made them superior to other men in the realm of leadership. As a result of these ideas and actions, many leading Jewish scientists left Germany and the Nazi leadership never succeeded in dealing with science and scientists satisfactorily.
At that time, the largest number of Nobel Prize winners were from Germany, the majority of whom were in Berlin, which made the city an important scientific centre. However, the scientific community was divided more than ever, which negatively impacted scientific work in physics. The era of the discovery of uranium fission coincided with this period of great political turmoil. The deterioration of the political situation in Germany encouraged scientists in neighbouring countries to leave for the United States to be away from European troubles. For example, Lars Onsager, a Norwegian who was studying in Switzerland, left in 1933; he was later awarded the Nobel Prize in chemistry. In 1940, Wilhelm Kroll, a metallurgist in Luxembourg, had to flee to the United States, where he later developed the titanium industry.
The German Jewish scientists who went to England under the persecution laws included Rudolph Peierls, a young research physicist from Berlin, and Franz Simon, a professor of physics at the University of Breslau (present-day Wroclaw) in Poland. As the Nazis gained more and more influence in Italy, they intensified persecution in that country. The specific persecution of Jews was added to the violence already practised by Mussolini. Fascism in Italy forced liberal scientists to leave their country.
Lise Meitner (1878-1967), who was born in Vienna, studied under Ludwig Boltzmann and Franz Exner at the University of Vienna. In 1907, she left for Berlin to attend Max Planck’s lectures at the University of Berlin. In Berlin, she met Otto Hahn who had just returned from abroad and started working on radiochemistry at the Chemistry Institute at the university. They worked together for many years. During the first years of the Nazi regime in Germany, she was safe from harm, even though she was Jewish, because she was an Austrian national. However, after the Anschluss in 1938, when Germany and Austria became one country, she was forced to leave. She settled first in Copenhagen but then had to escape to Stockholm when Denmark was occupied by the Nazis. She was a co-discoverer of protactinium.
Edgar Sengier (1879-1963) graduated from the University of Louvain in Belgium and occupied numerous positions with the Union minière du Haut Katanga. When Belgium was occupied by the Nazis in 1940, he moved his office to New York City. A year earlier, in 1939, he had been alerted by French and British scientists about the strategic importance of uranium. As a result, he had ordered 1,250 tons of rich ore to be shipped to the United States.
Niels Bohr (1885-1962), born in Copenhagen, worked with J.J. Thomson at Cambridge and with Rutherford at Manchester. In 1916, he became a professor of physics at Copenhagen. Bohr received the Nobel Prize for physics in 1922 for his work on the electronic structure of the atom. He escaped from Denmark when it was occupied by the Germans and became a scientific adviser to the British Government; later, he moved to the United States. Otto Frisch, Rudolph Peierls and others joined the American establishment at Los Alamos where the huge task of designing and building the manufacturing plant that made the atomic bombs was carried out.
John Cockcroft (1897-1967), educated at Manchester and Cambridge, was a professor at Cambridge from 1939 to 1946, the director of the Atomic Energy Division of Canada from 1944 to 1946 and, later, the director of the UK Atomic Energy Research Establishment. He shared the Nobel Prize in physics with Ernest Walton in 1951 for work on the disintegration of lithium by proton bombardment.
Leo Szilard (1898-1964) was born in Hungary and went to the Kaiser Wilhelm Institute in Berlin to conduct research under Albert Einstein. He fled Nazi Germany in 1933 to settle temporarily in London. When he learned of Rutherford’s sceptical view of releasing atomic energy, he went to see him at the Cavendish Laboratory in Cambridge and tried to explain to him his idea of a chain reaction, but without success. Szilard immigrated to America in 1939, where he met his fellow Hungarian refugee, Eugene Wigner, whom he had known at the Kaiser Wilhelm Institute and who had become a professor of physics at Princeton University. His visit coincided with that of Niels Bohr who carried the news from Copenhagen that the Germans were able to split the uranium atom. He was the first person to conceive of an atomic bomb.
Enrico Fermi (1901-1954) was born in Rome and studied at the University of Pisa. After receiving his doctorate in 1922, he went to Germany for a year and then taught at the University of Florence. In 1926, he became a professor of theoretical physics at the University of Rome. In 1938, he received the Nobel Prize for his work on slow neutrons. After the ceremony, instead of returning to Rome, where the Fascist regime was well established, he sailed to the United States where he joined the University of Chicago. There, in 1942, he and his coworkers successfully demonstrated the first sustained nuclear chain reaction, which led to the exploitation of nuclear energy.
Otto Frisch (1904-1979), a nephew of Lise Meitner, was born in Vienna. He obtained a doctorate in physics from the University of Vienna in 1926. After graduating, he left for Berlin to work at the Physikalische Technische Reichsanstalt. In 1930, he moved to Hamburg to accept a teaching assistantship but was fired from his position in 1933 because of the anti-Semitic laws introduced in Germany. He accepted a temporary position in London and a year later went to the Institute of Theoretical Physics in Copenhagen, under the direction of Niels Bohr. The German occupation of Denmark during World War II forced Frisch to move again, first to Birmingham University and then to Liverpool. In 1943, he acquired British citizenship, which enabled him to join the British delegation sent to the Los Alamos nuclear research centre in the United States, where he participated in developing the first atomic bomb. On his return to England, he became associated with the Atomic Energy Establishment at Harwell (near Oxford) until 1947, when he moved to the University of Cambridge.
Emilio Segrè (1905-1989), born in Tivoli, Italy, was a professor of physics at the University of Rome from 1932 to 1936 and at the University of Palermo from 1936 to 1938. He emigrated from Fascist Italy in 1938 to work at the University of California at Berkeley; from there, he went to Los Alamos. Segrè was the first person to produce a synthetic element, which he called technetium, by bombarding molybdenum with alpha particles. He received the Nobel Prize in physics in 1959.
Hans Bethe (1906-2005) was born in Strasburg in Alsace-Lorraine and studied in Frankfurt and Munich. He left Germany in 1933 to first go to England and then, in 1935, to Cornell University in the United States. He was the director of the Theoretical Physics Division at Los Alamos from 1943 to 1946. Bethe won the Nobel Prize in physics in 1967.
Edward Teller (1908-2003), who was born in Budapest, studied in Karlsruhe, Munich, Göttingen and Copenhagen. He left Germany in 1933, going first to England and then to the United States. He worked on the Los Alamos atomic bomb project (1941-1946) and then became a professor of physics at the University of Chicago and an advisor to President Truman’s program that built and tested the hydrogen bomb in 1952.
The young Austrian Jewish experimental physicist Hans Halban fled Austria to join Joliot in Paris and became a French citizen. Klaus Fuchs (1911-1988) left Germany for England in 1933 and then moved to the United States in 1943. A communist supporter, he was accused of transmitting nuclear secrets to the Russians during his participation in the Manhattan Project from 1943 to 1946. He was arrested in England and condemned to 14 years in prison. After serving his sentence, he became a refugee in the former German Democratic Republic.
The migration of scholars, whether voluntary or involuntary, due to persecution or otherwise, has played an important role in the diffusion of knowledge since ancient times. In addition, a number of enlightened monarchs have advanced their countries by hiring foreign experts, many of whom chose to stay on in their adopted countries. Travelling scientists certainly contributed to advancing knowledge by communicating their observations to others. Well-known professors attract students from different countries to study at their institutions, and the interaction among these students is of immense importance in the diffusion of knowledge. The examples examined in this series serve to illustrate the important role played by scholarly migration in the development of the sciences.