1932—Moving into the new physics
DOI: 10.1063/1.3070853
In 1972 we celebrate the fortieth anniversary of the “annus mirabilis” of nuclear and particle physics. Seen from the perspective of the present, the cluster of major conceptual and technical developments of 1932 mark that “marvelous” year as a very special one. It began with Harold Urey’s announcement in January that he had discovered a heavy isotope of hydrogen, which he called “deuterium.” In February James Chadwick demonstrated the existence of a new nuclear constituent, the neutron. In April John Cockcroft and E. T. S. Walton achieved the first disintegration of nuclei by bombarding light elements with artificially accelerated protons. In August Carl Anderson’s photographs of cosmic‐ray tracks revealed the existence of another new particle, the positively charged electron, soon to be called the “positron.” And later that summer Ernest Lawrence, Stanley Livingston and Milton White disintegrated nuclei with the cyclotron, an instrument that would generate almost 5‐million electron volts by the end of that eventful year.
References
1. J. Boyce to J. Cockcroft, 8 January 1932, Sir John Cockcroft Papers, Churchill College Library, Cambridge, UK.
2. C. D. Anderson to R. A. Millikan, 3 November 1931, Robert A. Millikan Papers, California Institute of Technology Archives, Pasadena. For Millikan’s account of his talks in Europe about the photographs, see R. A. Millikan, Electrons (+ and −), Protons, Photons, Neutrons and Cosmic Rays (Chicago, 1935), pages 327–330.
The reaction of some European physicists to these talks is documented and analyzed in N. R. Hanson, The Concept of the Positron (Cambridge, UK, 1963), page 139–142, 216–217.3. C. D. Anderson, Science 76, 238–239, 9 September 1932.https://doi.org/SCIEAS
4. Some of the 1932 nuclear events are also discussed in C. Weiner “Institutional Settings for Scientific Change: Episodes from the History of Nuclear Physics,” in A. Thackray and E. Mendelsohn, Science and Values (Humanities Press, N.Y.), in press.
5. J. Chadwick, “Some Personal Notes on the Search for the Neutron,” Proceedings of the 10th International Congress of the History of Science, Ithaca, 1962 (Paris, 1964), page 161.
6. J. Chadwick, “On the Possible Existence of the Neutron,” Nature 129, 312, 27 February 1932.https://doi.org/NATUAS
7. J. Chadwick to N. Bohr, 24 February 1932, and N. Bohr to J. Chadwick, 25 March 1932, Niels Bohr Papers, Niels Bohr Institute, Copenhagen, The Bohr Papers have been microfilmed by The American Physical Society–American Philosophical Society project on Sources for History of Quantum Physics, and the films are deposited at the American Philosophical Society, Philadelphia; at the Bancroft Library, University of California, Berkeley and at the AIP Niels Bohr Library, New York.
8. Information on the conferences is available in the Niels Bohr Institute administrative archive, Copenhagen.
9. Translation by Barbara Gamow in George Gamow, Thirty Years That Shook Physics, Doubleday, New York (1966), page 214.
10. For a full discussion of Heisenberg’s treatment of the neutron, see J. Bromberg, “The Impact of the Neutron: Bohr and Heisenberg,” in Historical Studies in the Physical Sciences, Vol. 3 (1971), page 307–341.
11. S. Goudsmit to N. Bohr, 4 November 1932. Niels Bohr Institute administrative archive, Copenhagen.
12. N. Bohr to S. Goudsmit, 28 December 1932, Niels Bohr Institute administrative archive, Copenhagen.
13. Interviews conducted in connection with the joint AIP–American Academy of Arts and Sciences conferences on the history of nuclear physics held in May 1967 and May 1969. The proceedings and abstracts of the interviews are now in press as part of the AIP Conference Proceedings Series.
14. E. Rutherford to N. Bohr, 21 April 1932, Niels Bohr Papers, Niels Bohr Institute, Copenhagen.
15. N. Bohr to E. Rutherford, 2 May 1932, Rutherford Papers, Cambridge University Library, Cambridge, UK.
16. Interview with J. Cockcroft by C. Weiner, 28 March 1967, Oral History Collection, AIP Niels Bohr Library, New York.
17. E. Lawrence to J. Cockcroft and E. T. S. Walton, 20 August 1932, Cockcroft Papers, Churchill College Library, Cambridge, UK.
18. Interview with M. S. Livingston by C. Weiner, 21 August 1967, Oral History Collection, AIP Niels Bohr Library.
19. E. Rutherford to W. Tisdale, 6 March 1933, Cockcroft Papers, Churchill College Library, Cambridge, UK.
20. E. Lawrence to J. Cockcroft, 2 June 1933, Cockcroft Papers, Churchill College Library, Cambridge, UK.
21. E. Rutherford to G. N. Lewis, 30 May 1933, G. N. Lewis Papers, Department of Chemistry, University of California, Berkeley.
22. F. Spedding to G. N. Lewis, 1 December 1934, Lewis Papers, Berkeley.
23. This data is drawn from the statistical study of the physics journal literature conducted by H. Small with the assistance of D. Schreibersdorf at the AIP Center for History and Philosophy of Physics under a National Science Foundation grant. Work‐in‐progress reports were presented by Small at the History of Science Society annual meetings in 1970 and 1971.
24. The brief sketch here is based on archival materials from the Lawrence Radiation Laboratory, the Cavendish Laboratory and the Bohr Institute in Copenhagen; physics‐department files at several US universities; Herbert Childs’s biography of Lawrence, An American Genius (Dutton, New York, 1968);
and on historical accounts of the cyclotron such as those by M. Stanley Livingston and Edwin M. McMillan in PHYSICS TODAY, October 1959, 18–34,
and Livingston’s Particle Accelerators: A Brief History (Harvard, Cambridge, 1969).25. D. Cooksey to M. S. Livingston, 8 June 1938, E. O. Lawrence Papers, Bancroft Library, University of California, Berkeley.
More about the Authors
Charles Weiner. American Institute of Physics, Center for History of Physics.
