Emil Rupp, Albert Einstein, and the canal ray experiments on wave-particle duality: Scientific fraud and theoretical bias

Historical Studies in the Physical and Biological Sciences

Volumn 37, Issue SUPPL., 2007, Pages 73-120

  van Dongen, Jeroen ^a  

^a NONE

Author keywords

Albert Einstein; Canal rays; Emil Rupp; Scientific fraud; Theoretical bias; Wave particle duality

Indexed keywords

EID: 35349011692     PISSN: 08909997     EISSN: 15338355     Source Type: Journal    
DOI: 10.1525/hsps.2007.37.S.73     Document Type: Article

References (272)

1. Walther Gerlach, Archive for History of Quantum Physics, interview with T.S. Kuhn on 18 Feb 1963, 30-31; microfilm viewed at the Deutsches Museum, Munich. The author is grateful to Suman Seth for drawing attention to this passage.
2. The retracted publications were: Emil Rupp, "Polarisation der Elektronen an freien Atomen," ZfP, 88 (1934), 242-246
3. "Polarisation der Elektronen in magnetischen Feldem," ZfP, 90 (1934), 166-176
4. "Versuche mit künstlich erzeugten Positronen," ZfP, 92 (1934), 485-512
5. "Versuche mit künstlich erzeugten Positronen," Zeitschrift für technische Physik, 15 (1934), 575-579
6. "Die Messung hoher Spannungen mittels Elektronenbeugung," AdP, 20 (1934), 594-600.
7. Emil Rupp, "Mitteilung," ZfP, 95 (1935), 851.
8. A slightly expanded version can be found in Dr. Emil Freiherr von Gebsattel. "Abschrift. Ärztliches Gutachten," 20 Mar 1935, EA 20 430.
9. "Bericht über die Vorgänge bei der Aufklärung der Arbeitsweise von E. Rupp im Hinblick auf seine Publikationen "Versuche mit künstlich erzeugten Positronen. ZS. f. Phys. 92 S. 485; vgl. auch ZS. f. techn. Phys. 15 S. 575," EA 20 425; the authors of this document were presumably Arno Brasch and Fritz Lange.
10. See also Ramsauer's circular to Johannes Stark, Max von Laue, Gustav Hertz, Richard Becker, Philipp Lenard, Max Wien, Arnold Sommerfeld, Jonathan Zenneck, Friedrich Krüger, Robert Pohl, Peter Debye, Walther Kossel, Karl Scheel, Karl Mey, Hans Rukop, Richard Fellinger, E. Hochheim, Ernst Rutherford, Irving Langmuir, 14 Jan 1935, EA 20 425.
11. Carl Ramsauer, "Mitteilung," ZfP, 96 (1935), 278
12. Rupp (ref. 3).
13. Werner Heisenberg, Die Physikalische Prinzipien der Quantentheorie (Leipzig, 1930), 59-60.
14. Anthony P. French, "The strange case of Emil Rupp," Physics in perspective, 1 (1999), 3-21.
15. One cannot easily underestimate its effect, e.g., L. Bohnenkamp to Rupp: "Thank you for sending the reprints, that I study carefully. Hopefully you will not immediately become Geheimrätlich because of the new symbiosis with the persona gratissima Einstein." 16 Dec 1926, MPIWG.
16. See Allan Franklin, The neglect of experiment (Cambridge, 1986), 242-243.
17. Emil Rupp, "Lebenslauf," EA 20 428
18. Emil Rupp, Über erregende Absorption und Tilgung der Phosphore (PhD dissertation, University of Heidelberg, 1922).
19. Emil Rupp, "Interferenzuntersuchungen an Kanalstrahlen," AdP, 79 (1926), 1-34.
20. For more on the early history of canal rays, Henk de Regt, "Eugen Goldstein, Wilhelm Wien en de kanaalstralen, 1886-1912," Gewina, 12 (1989), 110-129.
21. For an overview of Wien's work and a review of canal ray physics, see Wilhelm Wien, "Kanalstrahlen," Wilhelm Wien and Friedrich Harms, eds., Handbuch der Experimentalphysik, 14 (Leipzig, 1927),435-788
22. Eduard Rüchardt, "Kanalstrahlen," Rudolf Dittler, Georg Joos and Eugen Korschelt, eds., Handwörterbuch der Naturwissenschaften (2nd. edn., Jena, 1934), 754-767.
23. Wilhelm Wien, "Über das Leuchten der Kanalstrahlen," AdP, 70 (1923), 1-31, and chapt. 10,
24. "Allgemeine Theorie des Leuchtens der Kanalstrahlen," Wien (ref. 13), 732-746.
25. Wilhelm Wien, "Über das Leuchten der Kanalstrahlen bei hohen Drucken und die Frage der Verweilzeit," AdP, 76 (1925), 109-123
26. Rupp (ref. 11), 3, 21-22.
27. On the Michelson interferometer, Grant E. Fowles, Introduction to modern optics (New York, 1989), 63-66; on its historical uses
28. see Michel Janssen and John Stachel, The optics and electrodynamics of moving bodies (Berlin, 2004, Max Planck Institute for the History of Science, preprint 265), 15-21.
29. Rupp (ref. 11), 6.
30. Rupp (ref. 11), 9-11.
31. Fowles (ref. 16), 68-74.
32. Rupp wrote for the line width b ∼ λ√θ/m with θ the temperature and m for the atomic mass; Rupp (ref. 11), 9.
33. Rupp (ref. 11), 10; when defining φ Rupp only speaks of a lens "L. quot;
34. According to Rupp, 65 cm was the largest value for the maximum coherence length that was certain (Rupp [ref. 11], 1)
35. he referred to Lummer and Gehrcke (Otto Lummer and Ernst Gehrcke, "Ueber die Interferenz des Lichtes bei mehr als zwei Millionen Wellenlängen Gangunterschied," Verhandlungen der Deutschen Physikalischen Gesellschaft, 4 [1902], 337-346), who claimed even longer path differences. These claims were later withdrawn.
36. See Henri Buisson and Charles Fabry, "La largeur des raies spectrales et la théorie cinétique des gaz," Journal de physique, 2 (1912), 442-464, on 448.
37. For this theoretical value, see Buisson and Fabry (ref. 22)
38. α Balmer line when using a Geissler tube as source.
39. Rupp (ref. 11), 12-20.
40. Ibid., 22, 33.
41. See Robert Pohl to Rupp, 11 Apr 1926, MPIWG.
42. Eduard Rüchardt, "E. Rupp. Interferenzurnersuchungen an Kanalstrahlen," Physikalische Berichte, 7 (1926), 1523-1524.
43. Upon seeing Rijchardt's note, Rupp wrote him a letter claiming that, despite what the figure suggested, the pump was actually not immediately located at the canal (Rupp's letter is mentioned in another review by Rüchardt ["E. Rupp. Zur Lichtdauer der Atome. Abklingung bei den Alkalien und im Magnetfeld," Physikalische Berichte, 7 (1926), 2052]). Rüchardt, although willing to correct his review, was not quite convinced.
44. β than Rupp's coherence length allowed (E. Rüchardt to E. Rupp, 7 Oct 1926, MPIWG; Rüchardt referred in this letter to Atkinson [ref. 23]
45. and Martin C. Johnson, "The distribution of intensity in a positive ray spectral line," Physical Society of London, Proceedings, 38 (1925), 324-334
46. see also "Part II" ibid., 39 [1926], 26-38).
47. Walter Grotrian, "Interferenzuntersuchungen an Kanalstrahlen," NW, 14 (1926), 399-400.
48. Albert Einstein, "Vorschlag zu einem die Natur des elementaren Strahlungs-Emissionsprozesses betreffenden Experiment," NW, 14 (1926), 300-301.
49. Recent literature on Einstein's light quantum includes David C. Cassidy, "Einstein and the quantum hypothesis," AdP (Leipzig), 14, suppl. (2005), 15-22
50. Robert Rynasiewicz and Jürgen Renn, "The turning point for Einstein's annus mirabilis," Studies in history and philosophy of modem physics, 37 (2006), 5-35.
51. Albert Einstein, "Über ein den Elementarprozess der Lichtermission betreffendes Experiment," SBPAW, (1921), 882-883
52. reprinted in Michel Janssen, Robert Schulmann, József Illy, Christoph Lehner, Diana Kormos Buchwald, Daniel Kennefick, A.J. Kox, and David Rowe, eds., The collected papers of Albert Einstein, Vol. 7, The Berlin years: Writings, 1918-1921 (Princeton, 2002), 483-487.
53. Albert Einstein, "Theorie der Lichtfortpflanzung in dispergierenden Medien," SBPAW, (1922), 18-22.
54. For a historical discussion, see Martin J. Klein, "The first phase of the Bohr-Einstein dialogue," HSPS, 2 (1970), 1-39,
55. and the annotation of Document 68 in Janssen et al. (ref. 30).
56. On the Michelson interferometer, Grant E. Fowles, Introduction to modern optics (New York, 1989), 63-66
57. on its historical uses, see Michel Janssen and John Stachel, The optics and electrodynamics of moving bodies (Berlin, 2004, Max Planck Institute for the History of Science, preprint 265), 15-21.
58. Rupp (ref. 11), 6.
59. Rupp (ref. 11), 9-11.
60. Fowles (ref. 16), 68-74.
61. Rupp wrote for the line width b ∼ λ√θ/m with θ the temperature and m for the atomic mass; Rupp (ref. 11), 9.
62. Rupp (ref. 11), 10; when defining ψ Rupp only speaks of a lens "L"
63. According to Rupp, 65 cm was the largest value for the maximum coherence length that was certain (Rupp [ref. 11], 1)
64. he referred to Lummer and Gehrcke (Otto Lummer and Ernst Gehrcke, "Ueber die Interferenz des Lichtes bei mehr als zwei Millionen Wellenlängen Gangunterschied," Verhandlungen der Deutschen Physikalischen Gesellschaft, 4 [1902], 337-346), who claimed even longer path differences. These claims were later withdrawn.
65. See Henri Buisson and Charles Fabry, "La largeur des raies spectrales et la théorie cinétique des gaz," Journal de physique, 2 (1912), 442-464, on 448.
66. For this theoretical value, see Buisson and Fabry (ref. 22)
67. α Balmer line when using a Geissler tube as source.
68. Rupp (ref. 11), 12-20.
69. Ibid., 22, 33.
70. See Robert Pohl to Rupp, 11 Apr 1926, MPIWG.
71. Eduard Rüchardt, "E. Rupp. Interferenzuntersuchungen an Kanalstrahlen," Physikalische Berichte, 7 (1926), 1523-1524.
72. Upon seeing Rüchardt's note, Rupp wrote him a letter claiming that, despite what the figure suggested, the pump was actually not immediately located at the canal (Rupp's letter is mentioned in another review by Rüchardt ["E. Rupp. Zur Lichtdauer der Atome. Abklingung bei den Alkalien und im Magnetfeld," Physikalische Berichte, 7 (1926), 2052]).
73. β than Rupp's coherence length allowed (E. Rüchardt to E. Rupp, 7 Oct 1926, MPIWG;
74. Rüchardt referred in this letter to Atkinson [ref. 23] and Martin C. Johnson, "The distribution of intensity in a positive ray spectral line," Physical Society of London, Proceedings, 38 (1925), 324-334
75. see also "Part II," ibid., 39 [1926], 26-38).
76. Walter Grotrian, "Interferenzuntersuchungen an Kanalstrahlen," NW, 14 (1926), 399-400.
77. Albert Einstein, "Vorschlag zu einem die Natur des elementaren Strahlungs-Emissionsprozesses betreffenden Experiment," NW, 14 (1926), 300-301.
78. Recent literature on Einstein's light quantum includes David C. Cassidy, "Einstein and the quantum hypothesis," AdP (Leipzig), 14, suppl. (2005), 15-22
79. Robert Rynasiewicz and Jürgen Renn, "The turning point for Einstein's annus mirabilis," Studies in history and philosophy of modern physics, 37 (2006), 5-35.
80. Albert Einstein, "Über ein den Elementarprozess der Lichtemission betreffendes Experiment," SBPAW, (1921), 882-883
81. reprinted in Michel Janssen, Robert Schulmann, József Illy, Christoph Lehner, Diana Kormos Buchwald, Daniel Kennefick, A.J. Kox, and David Rowe, eds., The collected papers of Albert Einstein, Vol. 7, The Berlin years: Writings, 1918-1921 (Princeton, 2002), 483-487.
82. Albert Einstein, "Theorie der Lichtfortpflanzung in dispergierenden Medien," SBPAW, (1922), 18-22.
83. For a historical discussion, see Martin J. Klein, "The first phase of the Bohr-Einstein dialogue," HSPS, 2 (1970), 1-39,
84. and the annotation of Document 68 in Janssen et al. (ref. 30).
85. For Einstein's response to the Compton experiment, see Albert Einstein, "Das Komptonsche Experiment," Berliner Tageblatt, 20 Apr 1924, suppl. I.
86. Walther Bothe and Hans Geiger, "Über das Wesen des Comptoneffektes: Ein experimenteller Beitrag zur Theorie der Strahlung," ZfP, 32 (1925), 639-663
87. Albert Einstein, "Observações sobre a situação atual da teoria da luz," Revista da academia Brasileira de sciencias, 1 (1925), 1-3.
88. See also Anthony Duncan and Michel Janssen, "On the verge of Umdeutung in Minnesota: Van Vleck and the correspondence principle (part one)," preprint, 2006: http://uk.arxiv.org/abs/physics/0610192
89. Abraham Pais, "Interlude: The BKS proposal," in 'Subtle is the Lord...'The science and the life of Albert Einstein (Oxford, 1982), 416-422.
90. Walther Bothe, "Über die Kopplung zwischen elementaren Strahlungsvorgängen," ZfP, 37 (1926), 547-567.
91. For Einstein's enthusiasm for Bothe's results, see Einstein to Hendrik Antoon Lorentz, 13 Mar 1926, EA 16 595.
92. Our account here differs from Don Howard, "'Nicht sein kann was nicht sein darf,' or the prehistory of EPR, 1909-1935: Einstein's early worries about the quantum mechanics of composite systems," in Arthur I. Miller, ed., Sixty-two years of uncertainty: Historical, philosophical and physical inquiries into the foundations of quantum mechanics (New York, 1990), 61-109, on 85
93. see also Alexander Bach, "Eme Fehlinterpretation mit Folgen: Albert Einstein und der Welle-Teilchen Dualismus," Archive for history of exact sciences, 40 (1989), 173-206, on 184-185.
94. Note that Einstein's b is obviously different from Rupp's use of that symbol in figure 2.
95. As in Einstein (ref. 29), 301.
96. Einstein to Erwin Schrödinger, 26 Apr 1926, EA 22 018.
97. Paul Ehrenfest to Einstein, 7 Apr 1926, EA 10 134.
98. Georg Joos to Einstein, 25 Apr 1926, EA 13 164, EA 13 165.
99. Georg Joos, "Modulation und Fourieranalyse im sichtbaren Spektralbereich," PZ, 27 (1926), 401-402
100. see also the letters that Joos wrote to Einstein, 28 Apr 1926, EA 13 466; 9 May 1926, EA 13 467.
101. Atkinson (ref. 23)
102. he based his expectation for the coherence length on the theoretical analysis of Buisson and Fabry (ref. 22).
103. Einstein to Rupp, 20 Mar 1926, EA 70 701.
104. Rupp to Einstein, 23 Mar 1926, EA 20 386.
105. See Einstein to Rupp, 31 Mar 1926, EA 70 702.
106. For more on Lenard, see Charlotte Schönbeck, "Albert Einstein und Philipp Lenard: Antipoden in Physik und Zeitgeschichte," Schriften der mathematisch-naturwissenschaftliche Klasse der Heidelberger Akademie der Wissenschaften, 8 (2000), 1-42
107. Alan D. Beyerchen, Scientists under Hitler: Politics and the physics community in the Third Reich (New Haven, 1977)
108. Klaus Hentschel, ed., Physics and National Socialism: An anthology of primary sources (Basel, 1996).
109. Albert Einstein, "Über die Interferenzeigenschaften des durch Kanalstrahlen emittierten Lichtes," SBPAW (1926), 334-340.
110. The article was presented in the session of 8 Jul 1926 (see Einstein's abstract in the proceedings of that session [SBPAW (1926), 274]) and published in the proceedings of the session of 21 Oct 1926.
111. See Einstein to Rupp, 9 May 1926, EA 70 706
112. Einstein (ref. 45).
113. For a derivation, see Miles V. Klein and Thomas E. Furtak, Optics (2nd edn., New York, 1986), 284-307.
114. Einstein to Rupp, 31 Mar 1926, EA 70 702, emphasis in original.
115. This idea was already outlined by Einstein as early as 1922. See "Nederlandsche Natuurkundige Vereeniging. Vergadering op zaterdag 29 april 1922 in het natuurkundig laboratorium der Universiteit van Amsterdam," Physica: Nederlandsch tijdschrift voor namurkunde, 2 (1922), 158-159.
116. In that seminar, Einstein briefly suggested rotating the mirror of an interferometer in front of a canal ray source. The question this was to address was indeed the duration of light emission. However, Einstein did not initially recognize his idea of 1922 in Rupp's experiment, as exhibited by his initial incomprehension regarding how Rupp could have cancelled the relevant Doppler effect. By 1926 he may well have forgotten his earlier suggestion; a strong indication of this is that Einstein explained the idea of the mirror rotation again to Ehrenfest in 1926 without a reference to the seminar in Amsterdam (letter of 12 Apr 1926, EA 10 136), even though Ehrenfest had participated in the discussion there. It further seems that there is no mention of the seminar of 1922 in any of Einstein's correspondence of 1926 on the canal ray experiments - particularly not in his letters to Ehrenfest or Rupp. In 1922, the idea appears to only have come up on this occasion, suggesting that at that time it was of minor concern to Einstein.
117. Einstein to Rupp (ref. 48)
118. Einstein (ref. 45)
119. on its earlier occurrence in 1922, see note 49. In his analysis, Einstein once more first put the source at infinity, again allowed because of the symmetry in the arrangement and the particular kind of interferometer used.
120. Einstein to Paul Ehrenfest, 12 Apr 1926, EA 10 135.
121. The letter to Ehrenfest of 12 April (ibid.) suggests that Einstein was then already expecting a classical result for the canal ray experiments.
122. In a later letter to Erwin Schrödinger (26 Apr 1926, EA 22 018), Einstein still expressed that he believed that the particulate picture was going to be confirmed.
123. On 5 May he spoke out again in favor of the classical result (Einstein to Rupp, 5 May 1926, EA 70 705).
124. Einstein to Rupp, 18 Apr 1926, EA 70 703
125. Rupp to Einstein, 11 Apr 1926, EA 20 389.
126. A limited number of the arguments they exchanged are presented here, but these give a fairly complete and representative account of the dynamic.
127. Rupp to Einstein, 29 Apr 1926, EA 20 392.
128. Rupp to Einstein, 1 May 1926, EA 20 393.
129. Einstein to Rupp, 5 May 1926, EA 70 705.
130. For Rupp emphasizing the role of his slits, see ref. 55.
131. Einstein to Rupp, 9 May 1926, EA 70 706.
132. The manuscript of Einstein's publication (ref. 45) has survived and can be viewed online; see http://www.alberteinstein.info, document 1-54.00.
133. Rupp to Einstein, 14 May 1926, EA 20 395.
134. Einstein to Rupp, 18 May 1926, EA 70 707.
135. Ibid.
136. Rupp to Einstein, 20 May 1926, EA 20 397.
137. In Einstein's theory, the beam's velocity distribution was taken to be completely homogeneous; the relocation of the slit (B in figure 2) should therefore not have any effect. Rupp hinted that as the canal ray atoms move further away from the entry canal, their velocity distribution would be less homogeneous because of interactions. The slit in front of the canal ray beam would limit the light coming from the endpoint of the beam (ref. 62).
138. Einstein, in his reply, reminded Rupp that his original paper (ref. 11) had claimed that interactions with stationary atoms would not be an issue (Einstein to Rupp, 21 May 1926, EA 70 708).
139. Ibid.
140. Ibid.
141. Rupp to Einstein, 31 May 1926, EA 20 398.
142. Rupp to Einstein, 1 June 1926, EA 20 399.
143. Einstein to Rupp, 3 June 1926, EA 70 709.
144. Ibid.
145. See Rupp to Einstein, 15 June 1926, EA 20 400.
146. Ibid.
147. Emil Rupp, "Uber die Interferenzeigenschaften des Kanalstrahllichtes,: SBPAW, (1926), 341-351, on 348-349. The article was presented to the Prussian Academy by Einstein and appeared in the proceedings of the session of 21 Oct 1926.
148. For that manuscript, see ref. 58; Einstein's diagram is on page 4.
149. Rupp (ref. 72), 348-349.
150. Walther Gerlach and Eduard Rüchardt, "Über die Kohärenzlänge des von Kanalstrahlen emittierten Lichtes," AdP, 24 (1935), 124-126.
151. Carl Ramsauer to Walther Gerlach, 19 Aug 1935, GN 124-01. An inventory of the Gerlach Papers is available in Wilhelm Füßl, ed., "Der wissenschaftliche Nachlaß von Walther Gerlach (1889-1979)," Veröffentlichungen aus dem Archiv des Deutschen Museums, 3 (1998), 2 vols.
152. Atkinson (ref. 23).
153. Rupp to Einstein, 29 June 1926, EA 20 401.
154. Einstein to Rupp, 2 Jul 1926, EA 70 711.
155. Rupp to Einstein, 21 Aug 1926, EA 20 402.
156. Einstein to Rupp, 27 Aug 1926, EA 70 712.
157. Einstein to Rupp, 5 Nov 1926, EA 70 715.
158. Rupp to Einstein, 8 Nov 1926, EA 20 409.
159. A copy of such a reprint can be found in the Gerlach Nachlass, GN 124-03.
160. See Einstein (ref. 45), 340.
161. Rupp (ref. 72), 349-350.
162. Max von Laue, "Die Optik der bewegten Körper," in Wilhelm Wien and Friedrich Harms, eds., Handbuch der Experimentalphysik, 18 (Leipzig, 1928), 38-104, on 47-48, 58-60.
163. β in einem elektrischen Querfeld," AdP, 85 (1928), 515-528
164. Rudolf von Hirsch and Robert Döpel, "Die 'Axialität' der Lichtemission und verwandte Fragen," PZ, 29 (1928), 394-398
165. Emil Rupp, "Bemerkungen zu R. v. Hirsch u. R. Döpel: 'Die Axialität der Lichtemission und verwandte Fragen,'" PZ, 29 (1928), 625-626
166. Rudolph von Hirsch, "Erwiderung," PZ, 29 (1928), 730-731, on 731.
167. An overview of criticism of Rupp's work on canal rays during the years 1926-1928 can be found in the Gerlach Nachlass: "Bemerkungen zu Ruppschen Kanalstrahlarbeiten," GN 124-01
168. a more elaborate discussion of this episode is contained in French (ref. 7), 11-12.
169. Franklin (ref. 9), 227-229.
170. See also Olivier Darrigol, "A history of the question: Can free electrons be polarized?" HSPS, 15:1 (1984), 39-79, on 67-74,
171. and French (ref. 7), 12-13.
172. The paper under attack was Emil Rupp, "Über das magnetische Verhalten der Phosphore," AdP, 78 (1925), 505-557.
173. The proofs are entitled "Kritische Bemerkungen zur Abhandlung von Hrn. E. Rupp: 'Über das magnetische Verhalten der Phosphore.' Von Hans Buchner und Walther Gerlach." - "Erwiderung zu H. Buchner und W. Gerlach, Von E. Rupp." The typesetting is that of the Annalen der Physik; see GN 124-03.
174. The final publication is Hans Buchner, Walther Gerlach and Emil Rupp, "Bemerkungen zu der Abhandlung von E. Rupp 'Über das magnetische Verhalten der Phosphore,'" AdP, 8 (1931), 874-876.
175. According to Walther Gerlach, "Erinnerungen an Albert Einstein 1908-1930," in Peter Aichelburg and Roman Sexl, eds., Albert Einstein: Sein Einfluss auf Physik, Philosophie und Politik (Braunschweig, 1979), 199-210
176. Straub's thesis is Harald Straub, Über die Kohärenzlange des von Kanalstrahlen emittierten Leuchtens (PhD dissertation, University of Munich, 1930)
177. his results were also published in the Annalen der Physik, Harald Straub, "Über die Kohärenzlange des von Kanalstrahlen emittierten Leuchtens," AdP, 5 (1930), 644-656.
178. Wien's Handbuch review of the subject of 1927 (ref. 13) ominously did not include references to Rupp's work.
179. As in Straub, Annalen (ref. 91), 647
180. examples would be the texts of Heisenberg (ref. 6)
181. and von Lane (ref. 87).
182. This was an improvement of over 10% on the accepted value in the literature, indicating that he had a good optical arrangement.
183. See Straub, Annalen (ref. 91).
184. Rupp to Einstein, 12 Jul 1930, EA 20 416
185. Einstein to Emil Rupp, 17 Jul 1930, EA 20 418.
186. Hermann Mark to Rupp, 23 Aug 1930, MPIWG;
187. Rudolf Ladenburg to Rupp, 2 Sep 1930, MPIWG.
188. Max von Laue to Rupp, 28 Aug 1930, MPIWG;
189. Max von Laue and Rupp, "Über Elektronenbeugung an nichtmetallischen Einkristallen," AdP, 4 (1930), 1097-1120. This paper also contained an observation that von Laue soon found puzzling ("sehr sonderbar") and in need of further clarification.
190. See his attempt at the latter in Max von Laue, "Notiz zur Dynamik der Randschichten eines Kristalls vom NaCl-Typus. Zusatz zu der vorhergehenden Arbeit von M. v. Laue und E. Rupp," AdP, 4 (1930), 1121-1132.
191. Robert Pohl to Rupp, 19 Jul 1930, MPIWG.
192. Franz Wolf to Rupp, 21 Aug 1930, MPIWG.
193. Emil Rupp, "Erwiderung zu der Dissertation von H. Straub 'Über die Kohärenzlänge des von Kanalstrahlen emittierten Lichtes,'" AdP, 7 (1930), 381-384.
194. Straub's second draft is entitled "Über die Kohärenzlänge des von Kanalstrahlen emittierten Leuchtens. Bemerkung zu der Erwiderung von E. Rupp." It is contained in GN 124-01
195. Gerlach to Rupp, 2 Oct 1930, GN 124-01.
196. Eduard Grüneisen to Gerlach, 6 Oct 1930, GN 124-01.
197. Rupp to Gerlach, 5 Oct 1930; Rupp to Gerlach, 8 Oct 1930, GN 124-02.
198. Ibid.
199. "Das soll er mal ruhig veröffentlichen, da kann man ihn ja herrlich festnageln!" Harald Straub to Gerlach, 9 Oct 1930, GN 124-02.
200. Straub to Gerlach, 10 Oct 1930, GN 124-02. Much to Gerlach's chagrin, Rupp had managed to write a skewed review of Straub's original paper for the Physikalische Berichte, the German Physical Society's abstract publication (Emil Rupp, "Harald Straub. Über die Kohärenzlänge des von Kanalstrahlen emittierten Leuchtens," Physikalische Berichte, 11 [1930], 2154).
201. Gerlach corrected the situation by having his own review published, and made sure that the index only referred to his note (Eduard Rüchardt to Karl Scheel, 18 Oct 1930; Karl Scheel to Walther Gerlach, 25 Oct 1930; Walther Gerlach to Karl Scheel, 31 Oct 1930, GN 124-02; Walther Gerlach, "Harald Straub. Über die Kohärenzlänge des von Kanalstrahlen emittierten Leuchtens," Physikalische Berichte, 11 [1930], 2783).
202. Earlier Rupp had also sent Gerlach pictures of interference patterns. The Munich group measured these and concluded that Rupp could not have observed interferences at 20 cm path difference, but at 8 to 10 mm at best. Rupp next claimed that he had sent magnifications and that his originals complied with the larger path difference (Rupp to Gerlach, 16 Sep 1930; Gerlach to Rupp, 23 Sep 1930; Rupp to Gerlach, 24 Sep 1930; Gerlach to Eduard Grüneisen, 27 Sep 1930, GN 124-01).
203. Rupp to Gerlach, 17 Oct 1930; Gerlach to Rupp, 14 Oct 1930, GN 124-02.
204. As in Rupp (ref. 101), 384.
205. Ibid.
206. Harald Straub, "Über die Kohärenzlänge des von Kanalstrahlen emittierten Leuchtens. (Bemerkung zu der Erwiderung von E. Rupp)," AdP, 8 (1931), 286-292. The Gerlach Nachlass contains a letter from Straub to Gerlach (10 Oct 1930, GN 124-02) in which Straub states that he had drafted a protocol of observations done in Rupp's lab. The protocol would state that interferences were visible only during discharges, and would have been signed by Straub, the neutral observer Marianus Czerny, and Emil Rupp.
207. Robert Pohl to Rupp, 13 Jan 1931, MPIWG.
208. Emil Rupp, "Antwort auf die vorstehende Bemerkung von H. Straub," AdP, 8 (1931), 293-296, on 295.
209. Eduard Rüchardt to Einstein, 31 Oct 1930, EA 20 422.
210. Einstein to Eduard Rüchardt, 12 Nov 1930, GN 124-02.
211. Walther Gerlach to Eduard Grimeisen, 30 Jan 1931, GN 124-02.
212. See Straub, Annalen (ref. 112). Straub's statement of 2 Feb 1931 is found on page 292, its final page.
213. He published another paper showing that the homogeneity of the Hg canal ray beam did not improve for lower pressures: Harald Straub, "Die Breite des Dopplerstreifens im inhomogenen Kanalstrahl," AdP, 402 (1931), 670-671.
214. See letters by Arthur H. Compton to Emil Rupp, 6 Feb 1932, MPIWG; James Franck to Emil Rupp, 25 Jan 1932, MPIWG. It is important to note that in 1932 the AEG laboratory faced major budget cuts due to the economic depression and its staffing dropped from 75 to 44. See Detlef Lorenz, Das AEG-Forschungsinstitut in Berlin-Reinickendorf: Daten, Fakten, Namen zu seiner Geschichte 1928-1989 (Berlin, 2004), 12.
215. Robert Pohl to Rupp, 11 Feb 1932, MPIWG; Ramsauer to Stark et al. (ref. 4).
216. Lange and Brasch, according to Ramsauer in ibid.;
217. for references to Rupp's positron papers, see ref. 2.
218. Rupp (ref. 3)
219. Ramsauer (ref. 5)
220. the last according to Ramsauer (ref. 4).
221. For Ramsauer to Gerlach, see ref. 76
222. Gerlach and Rüchardt (ref. 75).
223. Undated typed document in the Gerlach Nachlass, GN 124-01. On the document is written in Gerlach's hand "Mitt. der Geschäftsversammlung der DPG 1935 an ihre Mitgl."
224. Lenard attended a rally for Adolf Hitler on 15 May 1926, right in the middle of the Einstein-Rupp collaboration (see Beyerchen [ref. 44], 97).
225. On the antagonism between Einstein and Lenard, see Schönbeck (ref. 44)
226. and the editorial note "Einstein's encounters with German anti-relativists," in Janssen et al. (ref. 30), 101-113.
227. Tensions between Berliners and southerners surfaced in 1920, during discussions on restructuring the DPG: See Paul Forman, "Il Naturforscherversammlung a Nauheim del settembre 1920: Una introduzione alla vita scientifica nella repubblica di Weimar," in Giovanni Battimelli, Michelangelo de Maria, and Arcangelo Rossi, eds., La ristrutturazione delle scienze tra le due guerre mondiali (Rome, 1984), 59-78.
228. Another contentious issue between Berliners and southern physicists was the creation of the journal Zeitschrift für Physik; see Einstein to Arnold Sommerfeld, 18 Dec 1919, doc. 219 in Diana Kormos Buchwald et al., eds., The collected papers of Albert Einstein, Vol. 9. The Berlin years: Correspondence January 1919-April 1920 (Princeton, 2004), 309-310
229. for an overview, see Paul Forman, "The financial support and political alignment of physicists in Weimar Germany," Minerva, 12 (1974), 39-66.
230. He also said that Rupp would still benefit from "supervision." Philipp Lenard to Wilhelm Wien, 14 June 1926, WN. See also Lenard to Wien, 19 Apr 1926, WN.
231. Philipp Lenard to Wilhelm Wien, 9 Jan 1927, WN.
232. Rupp (ref. 11)
233. Ref. 129.
234. Rupp (ref. 72).
235. Ref. 129.
236. Philipp Lenard to Wilhelm Wien, 23 Feb 1927, WN.
237. See Hubert Goenner, "The reaction to relativity theory I: The anti-Einstein campaign in Germany in 1920," Science in context, 6 (1993), 107-133
238. Jeroen van Dongen, "Reactionaries and Einstein's fame: 'German scientists for the preservation of pure science,' relativity and the Bad Nauheim conference," Physics in perspective, 9 (2007), 212-230.
239. Ref. 134.
240. See Straub, Annalen (ref. 91), 646.
241. Philipp Lenard, "Erinnerungen eines Naturwissenschaftlers, der Kaiserreich, Judenherrschaft und Hitler erlebt hat." Typescript, Heidelberg University, on p. 78; quoted excerpt dated at 1930/1, but according to its author, later additions had been made.
242. H. Billing, "Ein Interferenzversuch mit dem Lichte eines Kanalstrahles," AdP, 32 (1938), 577-592.
243. See Einstein to Walther Mayer, 10 or 11 Aug 1932, EA 18 130. On Einstein's collaboration with Mayer, see Jeroen van Dongen, "Einstein's methodology, semivectors and the unification of electrons and protons," Archive for history of exact sciences, 58 (2004), 219-254.
244. See Max von Lane to Emil Rupp, 24 Feb 1932, MPIWG.
245. For more on Deutsche Physik, or Aryan physics, and its opposition to Einstein's theories, see Beyerchen (ref. 44).
246. Max von Laue to Einstein, 8 June 1936, EA 16 110.
247. On von Laue, see Beyerchen (ref. 44), 64-66.
248. On Lenard, see Einstein to Max Born, 26 Oct 1920, Doc. 182 in Diana Kormos Buchwald et al., eds., The collected papers of Albert Einstein Vol. 10. The Berlin years: Correspondence May-December 1920 and supplementary correspondence 1909-1920 (Princeton, 2006), 468-469
249. Albert Einstein, "Meine Antwort. Ueber die antirelativitätstheoretische G.m.b.H," Berliner Tageblatt, 27 Aug 1920 (a.m. edn.), 1-2
250. Doc. 45 in Janssen et al. (ref. 30), 345-347.
251. French (ref. 7), 13.
252. Albert Einstein and Wander J. de Haas, "Experimenteller Nachweis der Ampèreschen Molekularströme." Verhandlungen der Deutsche Physikalische Gesellschaft, 17 (1915), 152-170
253. "Experimental proof of the existence of Ampère's molecular currents," Koninklijke Akademie van Wetenschappen te Amsterdam. Section of the sciences, Proceedings, 18 (1915-16), 696-711
254. (Docs. 13 and 14 in A.J. Kox, Martin J. Klein, and Robert Schulmann, The collected papers of Albert Einstein. Volume 6, The Berlin years: Writings 1914-1917 [Princeton, 1996], 150-189
255. see also its editorial note "Einstein on Ampère's molecular currents," pp. 145-149).
256. For the historical discussion of these experiments, see Peter Galison, How experiments end (Chicago, 1987), 21-74.
257. An interesting parallel may be drawn between the case of Rupp and Einstein's lenient attitude regarding the observational work on relativity of the astronomer Erwin Freundlich, who was also charged with serious scientific misconduct: Klaus Hentschel, The Einstein tower. An intertexture of dynamic construction, relativity theory, and astronomy (Stanford, 1997).
258. Paul Ehrenfest to Einstein, 16 Sep 1925, EA 10 110.
259. Einstein to Ehrenfest, 18 Sep 1925, EA 10 111.
260. On this shift, see Gerald Holton, "Mach, Einstein and the search for reality," Thematic origins of scientific thought: Kepler to Einstein (Cambridge, 1973), 219-259
261. John Norton, "'Nature is the realization of the mathematically simplest ideas': Einstein and the canon of mathematical simplicity," Studies in history and philosophy of modern physics, 31 (2000), 135-170
262. Jeroen van Dongen, Einstein's unification: General relativity and the quest for mathematical naturalness (PhD dissertation, University of Amsterdam, 2002).
263. On the discovery of general relativity, see Jürgen Renn, ed., The genesis of general relativity (4 vols., Dordrecht, 2007)
264. on its relation to Einstein's unified field theory program, see Michel Janssen and Jürgen Renn, "Untying the knot: How Einstein found his way back to field equations discarded in the Zurich notebook," in Michel Janssen, John Norton, Jürgen Renn, Tilman Sauer, and John Stachel, The Zurich notebook and the genesis of general relativity (Dordrecht, 2007), 839-925.
265. Klaus Hentschel, "Einstein's attitude towards experiments: Testing relativity theory, 1907-1927," Studies in history and philosophy of modern physics, 23 (1992), 593-624, on 612-613.
266. A different picture may emerge when considering his involvement with experimental physics in Leiden, see Tilman Sauer, "Einstein and the early theory of superconductivity, 1917-1922," Archive for history of exact sciences, 61 (2007), 159-211.
267. Von Laue (ref. 87).
268. See note 143.
269. Von Laue first held that nothing new could be learned from the Einstein-Rupp experiments since the results could be predicted on the basis of the Maxwell equations and the special theory of relativity (ref. 143).
270. In a second letter, he questioned, however, whether it was justified to presuppose an equivalence between an arrangement with the canal ray at infinity and an arrangement with the canal ray at a finite distance from the interferometer; see Max von Laue to Einstein, 29 Jul 1936, EA 16 111.
271. Einstein to Max von Laue, 29 Aug 1936, EA 16 113.
272. Ibid.