1. For the text and the signers of the Manifesto della razza , and on the subsequent period, see R. De Felice, Storia degli Ebrei italiani sotto il fascismo (History of the Italian Jews under Fascism), 3d ed. (Turin: Einaudi, 1972).

2. On Jenkins, see In Memoriam , University of California, Berkeley, 1962, F. A. Jenkins, 1899-1960. On Brode, see ibid. 1986, R. B. Brode (1900-1986), p. 2.

3. On the history of the Radiation Laboratory, see the works cited in chapter 5, n. 4.

4. See works cited in chapter 5, nn. 5, 6.

5. See Martin D. Kamen, Radiant Science, Dark Politics: A Memoir of the Nuclear Age (Berkeley and Los Angeles: University of California Press, 1985), which vividly portrays the Radiation Laboratory and the scientific climate in the United States before the war.

6. See A. A. Noyes and W. C. Bray, A System of Qualitative Analysis for the Rare Elements (New York: Macmillan, 1927).

7. Tables of natural radioactive isotopes go back to Curie, Rutherford, and their colleagues. With the discovery of artificial radioactivity, they became much larger. A first one was drawn up in Rome by our group and by G. Fea. I drew a useful diagram, following Heisenberg, while still in Rome. Later keeping such tables current required several people, and these days isotope tables are as thick as telephone directories.

8. E. Segrè and G. T. Seaborg, "Nuclear Isomerism in Element 43," Phys. Rev. 54 (1938): 772; ibid. 55 (1939): 808.

9. See also the work cited in chapter 5, n. 7, as well as U.S. Atomic Energy Commission, In the Matter of J. Robert Oppenheimer: Transcript of Hearing before Personnel Security Branch and Texts of Principal Documents and Letters (1954; Cambridge, Mass.: MIT Press, 1971), which gives a vivid picture, not only of Oppenheimer, but also of many other persons who testified at those hearings, among them Edward Teller, L.W. Alvarez, W. M. Latimer, H. A. Bethe, General Leslie Groves, and I. I. Rabi.

10. L. I. Schiff, Quantum Mechanics (New York: McGraw-Hill, 1955).

11. On S. K. Allison, see Bull. Atomic Scientists 22 (1966): 2.

12. F. A. Jenkins and E. Segrè, "The Quadratic Zeeman Effect," Phys. Rev. 55 (1939): 52.

13. E. Segrè, R. S. Halford, and G. T. Seaborg, "Chemical Separation of Nuclear Isomers," Phys. Rev. 55 (1939): 55.

14. E. Segrè, "An Unsuccessful Search for Transuranic Elements," Phys. Rev. 55 (1939): 1104.

15. E. Segrè and C. S. Wu, "Some Fission Products of Uranium," Phys. Rev. 57 (1940): 552, and "Radioactive Xenons," ibid. 67 (1945): 142.

16. On Placzek, see also Edoardo Amaldi, "George Placzek (1905-1955)," Ricerca scientifica 26 (1956): 2038.

17. Cornog, in Discovering Alvarez: Selected Works of Luis W. Alvarez, with Commentary by His Students and Colleagues, ed. W. P. Trower (Chicago: University of Chicago Press, 1987), p. 26. And see D. R. Corson, K. R. MacKenzie, and E. Segrè, "Possible Production of Radioactive Isotopes of Element 85," Phys. Rev. 57 (1940): 459, and "Artificially Radioactive Element 85," ibid. 58 (1940): 672-78.

18. E. Fermi and E. Segrè, "Fission of Uranium by Alpha Particles," Phys. Rev. 59 (1941); 59. FP135.

19. E. Segrè, "Possibility of Altering the Decay Rate of a Radioactive Substance," Phys. Rev. 71 (1947): 274; R. F. Leininger, E. Segrè, and C. E. Wiegand, "Experiments on the Effect of Atomic Electrons on the Decay Constant of Be7," Phys. Rev. 76 (1949): 897, and ibid. 81 (1951): 284.

20. See V. A. Johnson, Karl Lark-Horovitz: Pioneer in Solid State Physics (New York: Pergamon, 1969).

21. Birge was well known for his studies on molecular spectra and on universal constants, and also an important administrator at the University of California, to which he was deeply devoted. One of the physics buildings at Berkeley bears his name, well-deserved recognition of his work. See E. McMillan, "R. T. Birge, 1887-1980," in Am. Phil. Soc. (Philadelphia), Year-book, 1981 , p. 430.

22. R. T. Birge, "History of the Physics Department" (University of California, Berkeley, 1966-?; 5 vols., mimeographed).

23. See the documentation in G. T. Seaborg, Early History of Heavy Isotope Research at Berkeley , Lawrence Berkeley Laboratory Publication No. 97 (Berkeley, 1976). The archives of the Bancroft Library at the University of California, Berkeley, contain much additional material, including a letter from Segrè to Fermi dated January 11th, 1941, signaling the beginning of the work.

24. Many of these documents are to be found in the Bancroft Library.

25. G. T. Seaborg and E. Segrè, "The Transuranium Elements," Nature 159 (1947): 159; E. Segrè, E. M. McMillan, J. W. Kennedy, and A. C. Wahl,

"An Account of the Discovery and Early Study of Element 94," UCRL report No. 2791, Dec. 23, 1942.

26. Letter of G. T. Seaborg to Fermi, January 11, 1941, Bancroft Library.

27. J. W. Kennedy, G. T. Seaborg, E. Segrè, and A. C. Wahl, "Properties of 94 ²³⁹ ," Phys. Rev. 70 (1946): 555-56.

28. On A. L. Loomis, see L. W. Alvarez in Nat. Ac. of Sciences, Biographical Memoirs, vol. 51 (Washington, D.C.: National Academy of Sciences, 1980), p. 309.

29. See J. W. Kennedy and E. Segrè, "Component Analysis of Small Uranium Samples," Manhattan District Report MDDC-973, March 26, 1943.

30. E. Segrè, "Artificial Radioactivity and the Completion of the Periodic System of the Elements," Scientific Monthly 57 (1943): 57.

31. See, e.g., H. D. Smyth, Atomic Energy for Military Purposes (Princeton: Princeton University Press, 1945), the first and justly famous report on the atomic bomb. For details and documentation, consult R. G. Hewlett and O. E. Anderson, Jr., A History of the United States Atomic Energy Commission, vol. 1, The New World, 1939/1946 (University Park, Pa.: Pennsylvania State University Press, 1962).

32. A letter to Fermi written in 1942, now in the Bancroft Library, gives my feelings about going to Los Alamos.