12. Szilard to Fritz Lange, March 21, 1934 (LSP 11/20).
13. Maurice Goldhaber interview, December 4, 1985.
14. MIT Vol. II, pp. 36–38.
15. Murray to Szilard, April 27, 1934 (LSP 12/15); Szilard to Garnett, May 9, 1934 (LSP 8/23).
16. Eugene Wigner Memorandum, April 16, 1941: “Ideas Before the Discovery of Nuclear Fission” (LSP 65/23).
17. Szilard to Oliphant, May 20, 1934 (LSP 14/26).
18. This visit is mentioned in a letter by Walter Adams to Rutherford. See also Rutherford to Adams, May 30, 1934 (AAC SPSL, Sect. 4, Drawer 9, L. Szilard).
19. MIT Vol. II, p. 46. Rutherford recounted this meeting to Harvard spectroscopist Kenneth Bainbridge, whom he met in the hall. See “Orchestrating the Test” in Wilson, ed., All in Our Time p. 203. See also Blumberg and Owens, p. 86.
20. Szilard to Rutherford, June 7, 1934 (LSP 16/28).
21. Szilard to Felix Heim, July 19, 1934 (LSP 9/11).
22. Railing to Szilard, April 26, 1934, and Szilard to Railing, July 20, 1934 (LSP 8/28).
23. Paterson to Szilard, July 27, 1934 (LSP 8/28).
24. MIT Vol. II, pp. 37–38. Szilard to Railing, July 20, 1934 (LSP 8/28).
25. St. Cuilson and Paterson letters to Szilard, August 9, 1934, and Szilard to Paterson, August 14, 1934 (LSP 8/28).
26. At Szilard’s urging, Adams also asked Thomson if it might be worth approaching manufacturers “because of the possibility of its eventually being of importance for practical application.” Szilard to Walter Adams, July 23, 1934 (LSP 3/28). Adams to Thomson, July 24, 1934 (AAC SPSL Sect. 4, Drawer 9, L. Szilard).
27. G. P. Thomson to Walter Adams, July 26, 1934 (AAC SPSL, Sect. 4, Drawer 9).
28. Szilard to Simon, July 31, 1934 (FSP FS/14/3/S).
29. Szilard to Professor Singer, June 16, 1935 (LSP 18/3).
30. Szilard to Wigner, August 7, 1934 (LSP 21/4).
31. MIT Vol. I, p. 139.
32. Szilard to Hopwood, August 28, 1934 (LSP 9/40). See also MIT Vol. I, p. 143.
To an international conference on nuclear physics in London that September, Szilard explained his experiment this way: “By irradiating 25 gm. of beryllium with the penetrating radiation from 150 mgm. radium and exposing 100 c.c. ethyl iodine to the radiation excited in the beryllium we could induce radioactivity in iodine, and separate chemically the radioiodine from the ethyl iodine in the form of a silver iodide precipitate.” International Conference on Physics, London, 1934, Papers and Discussions in Two Volumes (Cambridge: The Physical Society, 1935). Vol. I, Nuclear Physics, pp. 88–89.
33. Szilard and Chalmers, “Chemical Separation of the Radioactive Element from Its Bombarded Isotope in the Fermi Effect.” Nature 134, p. 462 (September 22, 1934). MIT Vol. I, pp. 143–44.
34. International Conference, pp. 88–89.
35. MIT Vol. II, p. 20.
36. Szilard to Tristram Coffin, July 3, 1963 (LSP 6/22).
37. Szilard telegram to Polanyi, September 2, 1934 (MPP 14/9). Szilard to Polanyi, October 3, 1934, Josef Ernst translation (MPP unidentified correspondence 3/1).
38. MIT Vol. II, p. 40.
39. Nature 134, p. 880 (December 8, 1934). The work was completed on November 26, 1934. MIT Vol. I., pp. 140 and 148.
40. MIT Vol. I., p. 140.
41. “Atom Energy Hope Is Spiked by Einstein. Effort at Loosing Vast Force Is Called Fruitless.” Pittsburgh Post-Gazette headline, Section 2, p. 1, December 29, 1934, reporting Einstein’s visit to the city.
42. MIT Vol. I, p. 140.
43. Nature 135, p. 98 (January 19, 1935). MIT Vol. I, p. 140. Ugo Fano interview, March 17, 1987.
44. Nicholas Kurti interview, May 26, 1986.
45. See L. L. Whyte to Szilard, January 29, 1935 (LSP 21/2).
46. Nicholas Kurti interview, May 26, 1986.
47. Szilard to Lindemann, March 4, 1935 (LSP 12/7) and March 30, 1935 (FLP D. 23 1).
48. Wigner to Polanyi (MPP undated letters).
49. Szilard to C. K. Ogden, June 4, 1935 (LSP 14/23).
50. Isidor I. Rabi interview, August 19, 1985.
51. Dirac to Szilard, May 7, 1935 (LSP 7/15). “Book 1960” files (EWP).
52. Anna Kapitza interview (with Weiss and Patton), September 1988.
53. See Smithsonian Institution Negative No. 80-9568, Science Service of the Niels Bohr Library (AIP).
54. M. L. Oliphant, P. Harteck, and E. Rutherford, “Transmutation Effects Observed with Heavy Hydrogen,” Nature 133 (March 17, 1934), p. 413.
55. Hans Bethe interview, November 21, 1985. Bethe to the author, December 31, 1987.
56. FBI report, October 23, 1942 (LSP 95/9). Szilard to Professor Singer, June 16, 1935 (LSP 18/3).
57. The work with Chalmers led Szilard to conclude, mistakenly, that a “double” neutron, one with a mass of 2, might trigger such a process; in fact, he was observing an “isomer” of indium (having the same mass and atomic number) in a distorted radioactive state.
58. Szilard to Lindemann, June 3, 1935. MIT Vol. II, pp. 42–43.
59. June 6 draft for June 16, 1935, Szilard to Charles Singer (LSP 18/3).
60. Szilard to Charles Singer, June 16, 1935 (LSP 18/3). Dorothea Singer to Alice K. Smith, September 1, 1960. My thanks to Alice K. Smith for sharing this correspondence.
61. Szilard to Charles Singer, June 16, 1935 (LSP 18/3).
62. Esther Simpson interview, May 25, 1986.
63. Jean dePeyer Einersen to the author, December 16, 1987, and January 18, 1988.
64. Jean dePeyer Einersen to the author, January 18, 1988.
65. Szilard to Einersen, August 5, 1960. Quoted in her letter to the author on March 18, 1988.
66. DePeyer Einersen to Szilard, July 30, August 13, and September 12, 1960; his reply August 10, 1960 (LSP 7/12). Esther Simpson interview, May 25, 1986.
67. MIT Vol. II, p. 19.
68. MIT Vol. I, p. 186.
69. Walter Elsasser to the author, January 1, 1988.
70. Walter Elsasser interviews, November 12, 1985, and February 20, 1987.
71. J. Coombes to Claremont Haynes & Co., October 8, 1935 (EWP). Director of Navy Contracts to Szilard, March 25, 1936 (LSP).
72. Nicholas Kurti interview, May 26, 1986.
73. “Absorption of Residual Neutrons,” Nature 136, p. 950 (December 14, 1935). MIT Vol. I., pp. 140, 150–52. Rutherford to Szilard, December 17, 1935 (LSP 16/28).
74. Maurice Goldhaber in MIT Vol. I, p. 141.
75. Szilard to Breit and Wigner, January 12, 1936 (LSP 5/6). Niels Bohr to Szilard, February 4, 1936 (LSP 4/34).
76. Niels Bohr, “Neutron Capture and Nuclear Constitution,” lecture to the Royal Danish Academy of Sciences, reprinted in Nature 137, p. 348 (February 29, 1936).
77. Cockcroft to Szilard, January 22, 1936 (LSP 6/21).
78. Szilard to Fermi, March 13, 1936 (LSP 8/6).
79. Lindemann to Gen. Leslie Groves, July 12, 1945, with “Top Secret” attachment (MED 201, Szilard and Cherwell files).
At this time, Szilard had new reason to fear that nuclear weapons might be made. In his recent Nobel Prize lecture, Frédéric Joliot-Curie had predicted: “If we look back and take a glance at the progress achieved in ever-increasing measure in science, then we are justified in supposing that the investigators who are able to build up or break down elements at choice, will also learn how to realize transformations of an explosive character, veritable chemical chain reactions.” Frédéric and Irène Joliot-Curie, Oeuvres Scientifiques Complètes (Paris: Presses Universitaires de France, 1961), p. 552; Otto Hahn translation in New Atoms (New York: Elsevier, 1950), p. 29.
80. Szilard interview with Connie Lien, Glamour, January 5, 1962 (transcript, p. 2, in LSP 40/26).
81. Szilard to Fermi, March 13, 1936 (LSP S/6).
82. Goldhaber to Szilard, March 18, 1936. MIT Vol. II, p. 44.
83. Navy patent correspondence (LSP 4/2).
84. MIT Vol. II, pp. 44–45.
85. Szilar
d to Gertrud Weiss, March 26, 1936, Bela Silard translation (LSP 20/9).
86. Szilard left England for Calais on April 14, 1936, and entered Switzerland from Delle on April 16 (LSP 1/6). Gertrud Weiss Registration Certificate #598560 (EWP).
87. Szilard to Cockcroft, May 27, 1936 (LSP 6/21).
88. Szilard to Segrè, March 30, 1936 (LSP 17/18).
89. Szilard to Rutherford, May 27, 1936. MIT Vol. II, pp. 45á46.
CHAPTER 12
1. Nicholas Kurti interview, May 26, 1986.
2. Germany signed a treaty guaranteeing Austrian neutrality on July 11, 1936.
3. Attachment to October 11, 1943, court settlement; see especially pp. 4 and 8 (LSP 3/31-2).
4. Szilard to Arno Brasch, January 16, 1937 (LSP 5/4).
5. Szilard to Trude, March 31, 1937. Josef Ernst translation for this and all other personal letters between Leo and Trude (EWP).
6. Szilard to Trude, April 4, 1937 (EWP).
7. Hoover/Kreithe Navy report, 1942 (LSP).
8. Szilard to Trude, April 7, 1937 (EWP).
9. Szilard to Trude, April 13, 1937 (EWP).
10. Szilard to Trude, April 20, 1937 (EWP).
11. 1/4 Stmt, to N-400 (LSP 1/25, 2/9). FBI report, October 6, 1942 (LSP 95/9). See also April 20, 1937, Szilard to Trude (EWP).
12. Szilard to Brasch, July 3, 1937 (LSP 5/4).
13. Lindemann to Szilard, July 30, 1937 (FLP D.237).
14. Szilard to Trude, August 27, 1937 (EWP).
15. Szilard to Trude, September 3, 1937 (EWP).
16. Szilard to Trude, September 1 and 6, 1937 (EWP).
17. Roland Detre interview, October 1, 1986. Szilard to Trude, September 1, 1937 (EWP).
18. See Szilard to Lindemann, September 15, 1937 (FLP D.237).
19. Goldhaber in MIT Vol. I, p. 141. Maurice Goldhaber interview, December 4, 1985.
20. Joliot-Curie to Szilard, November 26, 1937 (LSP 10/23).
21. Szilard to Joliot-Curie, December 24, 1937 (LSP 10/23).
22. ICI to Szilard, December 31, 1937 (LSP). MIT Vol. II, p. 21.
23. Isidor I. Rabi interview, August 19, 1985.
24. Sent by Karl Polanyi on a Thursday from London, Bela Silard translation (MPP undated correspondence).
25. Gertrud Weiss Szilard’s “Identification and Personnel Data for Employment of United States Citizen,” September 8, 1961 (LSP). Frances Racker interview, November 22, 1985.
26. Szilard to Francis Simon, July 22, 1938, Josef Ernst translation (LSP 18/1).
27. Strauss correspondence in Szilard, Leo (LLS). See also Szilard’s 1/4 Stmt, to N-400 (LSP 1/25, 2/9).
28. Szilard to Lindemann, March 11, 1938 (FLP D.237).
29. Pfau, pp. 52–53.
30. Szilard to Francis Simon, July 22, 1938, Josef Ernst translation (LSP 18/1).
31. Strauss, p. 165. “Memorandum concerning my recollection of the conversations which I had with Mr. Strauss during 1938,” February 16, 1949 (LSP 41/11). Strauss remembers this as “toward the end of 1937” (p. 164), but Szilard was not in the United States then. See also Pfau, p. 53.
32. As he had done in London, Szilard turned to the handiest radiation source, a hospital, and in April arranged to have Dr. M. Lenz at the Montefiore Hospital for Chronic Diseases irradiate six cigars with 100 kilovolts for ten minutes on a side. “I hope,” Lenz wrote when returning the cigars to Szilard, “that your friend finds the taste unchanged.” Lenz to Szilard, April 15, 1938 (LSP). Cited in Rhodes, p. 239. In May, a Havana tobacconist wrote Szilard that his irradiated cigars had no difference in taste from untreated samples. Correspondent to Szilard, May 7 or 27, 1938 (LSP).
33. Elsbeth Liebowitz interview, October 2, 1986.
34. Szilard recommended irradiating the trichina worms, not to kill them but to sterilize them, thus preventing them from laying eggs. This strategy proved to be effective years later: Pork irradiation became a commercial process in many countries by the 1970s and was approved by the US Food and Drug Administration in 1986.
35. Szilard’s US-U.K. arrangement was initialed and dated May 6, 1938, by Lindemann. Chapman to Szilard, May 17, 1938; Lindemann to Szilard, June 6, 1938 (LSP 12/7).
36. Segrè oral-history interview, p. 31 (AIP). Rhodes, p. 240.
37. Szilard to Francis Simon, July 22, 1938 (LSP 18/1).
38. Lindemann to Szilard, July 30, 1938 (LSP 12/7).
39. Simon to Szilard, August 23, 1938, Bela Silard translation (LSP).
40. Szilard to Simon, September 9, 1938 (FSP FS/14/3/5).
41. Maurice Goldhaber interview, December 4, 1985.
42. MIT Vol. I, p. 155ff.
43. Szilard to Trude, October 2, 1938 (EWP).
44. A night letter to Lindemann late in October announced: “HAVING ON ACCOUNT OF INTERNATIONAL SITUATION WITH GREAT REGRET POSTPONED MY SAILING FOR AN INDEFINITE PERIOD STOP WOULD BE VERY GRATEFUL IF YOU COULD CONSIDER ABSENCE AS LEAVE WITHOUT PAY STOP WRITING STOP PLEASE COMMUNICATE MY SINCERELY FELT GOOD WISHES TO ALL IN THESE DAYS OF GRAVE DECISIONS SZILARD.” MIT Vol. II, pp. 21 and 48.
45. Sidney Barnes interviews, November 8 and 11, 1985.
46. Victor Weisskopf interview, December 16, 1985.
47. Sidney Barnes interviews, November 8 and 11, 1985.
48. Szilard to Bohr, November 11, 1938 (LSP 4/34).
49. Invitation to Dunning’s January 16, 1939, seminar (LSP 6/26).
CHAPTER 13
1. MIT Vol. II, p. 60.
2. James Arnold interview, February 11, 1987.
3. MIT Vol. II, pp. 50–52.
4. Niels Bohr had learned the news from Lise Meitner, the Austrian physicist who worked at the Kaiser Wilhelm Institute for Chemistry in Berlin but was then on holiday in Sweden, having just fled Nazi racial restrictions. She had learned of the experiment in a letter from Strassmann and with her nephew Otto Frisch immediately recognized—and named—the process of nuclear “fission.”
5. Herbert L. Anderson, “The Legacy of Fermi and Szilard.” Bulletin of the Atomic Scientists, September 1974, pp. 56–61, and October 1974, pp. 40–47.
See also Lawrence Badash, Elizabeth Hodes, and Adolph Tiddens, “Nuclear Fission: Reaction to the Discovery,” IGCC Research Paper No. 1, p. 16 (hereafter referred to as IGCC #1).
6. Wells described atomic warfare in his 1914 book The World Set Free, which Szilard first read in Berlin in 1932.
7. MIT Vol. II, p. 53.
8. Szilard telegram to Trude, January 23, 1939 (EWP).
9. IGCC #1, p. 16.
10. MIT Vol. II, p. 60.
11. IGCC #1, pp. 22 and 47. Edward Teller to the author, September 16, 1988.
12. IGCC#1, pp. 23 and 47.
13. An Early Time—Edward Teller. Los Alamos Scientific Laboratory Film.
14. MIT Vol. II, p. 54. At the moment, Szilard and Teller were among the few physicists who had looked beyond the stunning scientific news of fission to consider its use as a weapon. Another who saw its consequences was J. Robert Oppenheimer, a brash and brilliant thirty-five-year-old theoretical physicist at Berkeley. At first, when Luis Alvarez told him about uranium fission, Oppenheimer “proved” with stunning logic that it was impossible, posing several arguments about the technical barriers that must be over come. But a few hours later, once Oppenheimer had seen the pulses on a neutron monitor, he began speculating—about power-production plants and about bombs. Within days Oppenheimer guessed that a “ten cm cube of uranium deuteride . . . might very well blow itself to hell.” IGCC #1, pp. 22 and 25.
15. MIT Vol. II, p. 54.
16. Bernard T. Feld interview, January 13, 1987.
17. See, for example, Szilard’s “Book” ms “Apology (in lieu of a foreword),” pp. 4–5 (LSP 40/4).
18. MIT Vol. II, p. 61.
19. Ibid., p. 69–70, note 24.
20. Ibid., p. 55.
21. Ibid., pp. 55 and 63.
22. A high-energy “fast” neutron moves at about one-thirtieth the speed of light, or 10 million meters a second. “S
low” neutrons move at about 2,200 meters a second.
23. I. Miller to S. E. Krewer, February 21, 1939, and S. E. Krewer to Gertrud Szilard, March 22, 1978 (LSP 10/26).
24. IGCC #1, pp. 23 and 47. Newsweek, February 6, 1939.
25. IGCC #1, pp. 23 and 47. “Release of Atomic Energy Disclosed . . . .” Science Service, January 28, 1939.
26. “Is World on Brink of Releasing Atomic Power?” Science Service, January 30, 1939.
27. “Releasing of Atomic Energy . . . ” Science Service, January 30, 1939. My thanks to Ralph Lapp for this source.
28. Szilard had proposed a similar organization to Fermi in March 1936. Szilard to Strauss, February 13, 1939. MIT Vol. II, p. 63.
29. MIT Vol. II, pp. 63–65.
30. Receipt from “US Appraiser Stores, 201 Varick St., 7th Subs, West Houston Street, New York” (LSP).
31. Walter Zinn to the author, September 12, 1987.
32. William L. Laurence, Dawn over Zero (New York: Knopf, 1946).
33. Szilard Memoranda February 24 and March 3, 1939 (LSP 41/3).
34. Remarks at a banquet for the eightieth anniversary of The Nation, December 3, 1945. Reprinted in MIT Vol. II, p. 55.
35. Teller, The Legacy of Hiroshima, p. 10.
36. Herbert L. Anderson, “The Legacy of Fermi and Szilard,” p. 61. The paper “Neutron Production and Absorption in Uranium” by Anderson, Fermi, and Szilard was published August 1, 1939, in the Physical Review, Vol. 56, pp. 284–86.
37. Szilard cable to Strauss, March 4, 1939 (LLS Szilard, Leo 1936–39, Box 109).
38. Strauss, p. 174.
39. Szilard’s US Patent Application No. 10,500 was filed March 11, 1935; others were filed in England on March 12, May 9, June 14 and 28, July 4, and September 20 and 25, 1934 (LSP 35/40 and 36/1–11).
40. Strauss appointment book (LLS Box 19).
41. Szilard Memorandum to Compton, November 12, 1942 (MED 201).
42. Wigner interview in “The Man Behind the Bomb,” Japanese Television documentary, 1979.
43. Others attending the meeting were Wigner, George Placzek, Leon Rosenfeld, and John A. Wheeler. See Wheeler’s “Discovery of Fission,” Physics Today, November 1967, pp. 49–52. IGCC #1, pp. 25 and 48. Stuewer, p. 282. Wheeler interview, November 18, 1985. Barton Bernstein introduction, MIT Vol. Ill, p. xxix.
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