The Turing Guide

494 | NOTES TO PAGES 112–120

30. I. J. Good, ‘From Hut 8 to the Newmanry’, in Copeland et al. (2006), p. 205.


31. Good (Note 30), p. 205.


32. J. Murray (née Clarke), ‘Hut 8 and Naval Enigma, Part I’, in Hinsley & Stripp (1993), p. 114.


33. Murray (Note 32), pp. 113–15.


34. R. Erskine, ‘The first Naval Enigma decrypts of World War II’, Cryptologia, 21 (1997), 42–6, p. 43.


35. ‘Squadron-Leader Jones’ Section’ (Note 16), p. 14; see also K. McConnell, ‘My secret war’, Dundee City
    Library (10 November 2005) (http://www.bbc.co.uk/history/ww2peopleswar/stories/06/a6844106.
    shtml). I am grateful to Edward Simpson for drawing my attention to this article.


36. ‘Squadron-Leader Jones’ Section’ (Note 16), p. 3.


37. ‘Squadron-Leader Jones’ Section’ (Note 16), p. 1.


38. ‘Squadron-Leader Jones’ Section’ (Note 16), p. 10.


39. ‘Meeting held on 6th July 1950’ (Note 19), p. 1; ‘Squadron-Leader Jones’ Section’ (Note 16), p. 14.


40. Welchman (Note 26), p. 139.


41. ‘Tentative brief description of equipment for Enigma problems’, US National Archives and Records
    Administration, RG 457, Entry 9032, Historic Cryptographic Collection, pre-World War I through
    World War II, Box 705, no. 1737; ‘Bombes – Notes on Policy and Statistics, 1939–1950’, GC & CS,
    1950, NA HW25/21.


42. C. H. O’D. Alexander, ‘Cryptographic history of work on the German Naval Enigma’ (c.1945), NA
    HW25/1, p. 90; a digital facsimile of Alexander’s typescript is available in The Turing Archive for the
    History of Computing (http://www.AlanTuring.net/alexander_naval_enigma).


43. ‘Squadron-Leader Jones’ Section’ (Note 16), p. 8.


44. ‘Hut 6 Bombe Register’, GC & CS, 1940–1945, 2 vols, NA HW25/19, HW25/20; ‘Squadron-Leader
    Jones’ Section’ (Note 16), p. 8.


45. ‘Squadron-Leader Jones’ Section’ (Note 16), p. 4.


46. ‘Operations of the 6812th’ (Note 7), pp. 59, 60.


47. P. Mahon, ‘History of Hut 8 to December 1941’, in The Essential Turing, p. 291.


48. Alexander (Note 42), p. 25.


49. The indicator drums displayed the bombe’s guess at the so-called ‘rod position’ of the wheels—that is,
    the position of the wheels relative to a notional ring-setting of ZZZ.


50. ‘Squadron-Leader Jones’ Section’ (Note 16), p. 3.


51. A number of typical bombe menus are shown in ‘Operations of the 6812th’ (Note 7), pp. 8ff.


52. D. Payne, ‘The bombes’, in Hinsley & Stripp (1993), p. 134.


53. Mahon (Note 47), p. 293.


54. Copeland, ‘Enigma’ (Note 5), pp. 245–6.


55. Turing’s procedure is described in detail in Turing (1940), pp. 315–19, and Copeland, ‘Enigma’
    (Note 5), pp. 250–3.


56. Mahon (Note 47), p. 286.


57. Op. 20 GM-1 war diary, US National Archives and Records Administration, RG 38, NSG Records,
    CNSG Library, Box 113, no. 5750/176; I am grateful to Ralph Erskine for this reference.


58. W. F. Friedman, ‘Report on E Operations of the GC & CS at Bletchley Park’, US National Archives
    and Records Administration, RG 457, Entry 9032, Historic Cryptographic Collection, pre-World
    War I through World War II, Box 1126, no. 3620, p. 6; R. D. Johnson, ‘Cryptanalytic report # 2 Yellow
    Machine’, Historic Cryptographic Collection, Pre-World War I through World War II, Box 1009, no.
    3175, p. 12. I am grateful to Ralph Erskine for these references.


59. Denniston (Note 2), p. 3.


60. Mahon (Note 47), p. 303.


61. ‘Operations of the 6812th’ (Note 7), p. 3, and Johnson (Note 58), p. 88.


62. For details of this raid and other ‘pinches’ of Enigma materials on the high seas, see Turing (Copeland
    2012), Chapter 5.


63. Turing (1940), p. 315.


64. Turing (1940), pp. 316–17.