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In the fall of 1935 Melvin Calvin arrived in Manchester from the University of Minnesota, in order to begin a two-year postdoctoral period with support from Polanyi's Rockefeller Foundation funding. Calvin began by studying platinum-hydrogen activation systems, but found Polanyi speculating that biological oxidation might depend on a catalytic hydrogenation reaction taking place on a porphyrin molecule (like heme or chlorophyll) analogously to hydrogenation with platinum. Upon hearing that R. P. Linstead had just synthesized the porphyrin analog phthalocyanine at Imperial College, Polanyi sent Calvin to London to learn how to make and purify the phthalocyanine molecule. Calvin, E. G. Cockbain, and D. D. Eley then used phthalocyanine to study hydrogen activation in biologically-significant reactions.[23]

Calvin, who spent most of his career at Berkeley, received the Nobel Prize in Chemistry in 1961 for his work on chlorophyll and photosynthesis, work that was strongly influenced by the early studies of hydrogen catalysts, the use of deuterium as a tracer element, and investigations in Polanyi's laboratory on chemiluminescence. In recalling his years at Manchester, Calvin noted fondly a personal closeness to Polanyi that was not duplicated when they were colleagues at Oxford in 1967. He also noted that by the end of his stay in Manchester, in 1937, Polanyi was becoming more difficult to talk to about chemistry and more focussed on economics and philosophy, which was of less interest to Calvin.[24]

At Berlin Polanyi had about twenty-five collaborators in his laboratory in the early 1930s. I am not sure how many there were in Manchester. Lively colloquia and seminars had been common, and indeed famous, in Berlin, in the 1920s and early 1930s. Wednesday seminars in theoretical physics at the University of Berlin were the way people met each other, usually attended by some 150 to 200 people.[25] At Manchester there was a considerably smaller but nonetheless lively community of physical scientists and a tradition of joint colloquia of chemists and physicists, although I do not know whether there are records of them. The historian of Manchester chemistry G. N. Burkhardt noted that Polanyi organized research colloquia that sometimes lasted several days.[26]

Manchester, like Berlin, was a site of regular visitors by foreigners in the early decades of the 1900s. During the forced Jewish exodus from central Europe during 1933-1934, Hans Bethe and Rudolf Peierls were in Bragg's Manchester laboratory for a time before Bethe moved to Cornell University and Peierls went over to the Cavendish and then took a post in Birmingham.[27] As suggested above, there were close connections between Manchester and Princeton University through the Hungarians Wigner and von Neumann, as well as through Henry Eyring and the British-born and educated Hugh Taylor.[28]

It needs to be noted too, that just as in the laboratories in Berlin, so in Manchester there were close links, and often financial arrangements, between the laboratory and local industry. This had to do with the technology of electric-bulbs and gas illumination, photography, textiles, and pharmaceuticals, as well as vacuum and machine technology. The German tradition of precision instrumentation may have been missed by Polanyi when he first came to Manchester, and Blackett and others may have overly romanticized the British backwardness of string and sealing wax, but the reciprocity between innovations in the physical laboratory and in industry was clear to everyone by the mid-1930s.

In 1933 Blackett wrote a superb essay addressing some of these points. Entitled `The Craft of Experimental Physics,' written for a volume on university studies at Cambridge; it is an essay which bears reading for its every word and nuance.[29] A graduate of the University of Cambridge, Blackett never took a Ph.D. Among his first experiments in Rutherford's laboratory was a series of photographs of vapor tracks in a cloud chamber confirming the ejection of a hydrogen nucleus from a recoiling nitrogen atom that had been bombarded by alpha particles. From 20,000 photographs and 400,000 tracks, a few were selected and published in the Proceedings of the Royal Society of London in 1925. These widely-reprinted photographs confirmed Rutherford's theory and made Blackett's reputation as a young physics star.[30]

Following a year with James Franck in G”ttingen, where he became acquainted with Heisenberg among others, Blackett returned to the Cavendish where he continued to improve methods of detection of charged particles and became interested in cosmic rays as they were becoming a major field of controversy. This interest led to a stunning paper with G.P.S. Occhialini who had come to work with Blackett in 1930.

In late 1932 the two captured in photographs the track of a positive electron in a shower of cosmic rays. The experimental success was seated in the clever design by Blackett using Geiger counters to trigger expansion of the gas in the Wilson chamber. The theoretical explanation lay in the quantum-mechanical theory of Paul Dirac and Dirac's prediction of an anti-matter for the electron, a kind of energy hole. Dirac was sufficiently interested in Blackett's experiments that he was often at the laboratory.[31] Carl Anderson, who detected the anti-particle in Pasadena, told Charles Weiner in an interview, that although he published before them, the Blackett-Occhialini paper was the first to clearly bring out the idea of pair production as the proper explanation of the experimental effect.[32]

Blackett's move to Birkbeck College in 1933 coincided with the establishment at Cambridge of the new Royal Society Mond Laboratory for Kapitza. Blackett doubtless wanted a laboratory of his own, which was made possible by the offer of a professorship at Birkbeck. Blackett had frustrations with Rutherford at this time that were shared by James Chadwick, among others.[33]

The laboratory facilities at Birkbeck were disappointing, however, and remained so. Otto Frisch arrived there in October 1933 on the recommendation of Otto Stern and later recalled that the lab steward considered it an extravagance to buy even an extra piece of rubber tubing. Frisch began to buy his supplies at Woolworth's, including pencil caps for the geiger counters that he used in looking for gamma radiation produced by the annihilation of positrons with electrons. There were no formal seminars, but there were informal discussions over lunch or over tea about the nature and properties of cosmic rays, the positron, the neutrino, and the discovery in Paris of artificial radioactivity.[34]

In 1937 Blackett succeeded Bragg at Manchester. He wrote Rutherford of his pleasure at the greatly increased facilities that Manchester would provide him. To succeed Schuster, Rutherford, and Bragg, he wrote, would be very different than coming to Birkbeck. Nor was Manchester unfamiliar, since Blackett had been external examiner there for three years.[35] Records of negotiations for the Manchester position are not to be found in the Blackett Papers at the Royal Society, but Bernard Lovell notes that sweeping changes occurred at Manchester immediately after Blackett's arrival.

A departmental library was established, the dark brown walls were painted, workshops were shifted around, and adjacent domains were seized for installation of a large magnet and cloud chamber. Lovell notes that reassignments of Manchester personnel were made: of the original members of Bragg's staff, only S. Tolansky stayed on to carry on present research. J. M. Nuttall and E. C. Scott-Dickson took on the brunt of senior and junior teaching, with Lovell and G. D. Rochester serving as assistant lecturers. Douglas Hartree was reappointed from a professorship of applied mathematics to a chair of theoretical physics.[36] Blackett's later support of Lovell's work in the development of radio astronomy was central to Lovell's achievements at Jodrell Bank after the War.

Blackett brought with him from Birkbeck L. Janossy and J. G. Wilson. Visitors in the next years included Occhialini and B. Rossi, as well as Homi Jehangir Bhaba and Walther Heitler. Whereas Blackett was working in his research on the hypothesis that the very penetrating particles in cosmic rays were electrons, Heitler and Bhaba, who previously had worked with Blackett at the Cavendish (taking his Ph.D. in 1935), believed the penetrating particles were photons.[37]

Both views were wrong. Photographs taken by Carl Anderson confirmed in 1937 that penetrating cosmic-ray particles existed having a mass intermediate between electrons and protons, giving support to Hideki Yukawa's theory of nuclear forces using a particle about 200 times heavier than the electron. However, Anderson's particle, later called the mu-meson or muon, did not have the precise properties required by Yukawa's theory. At a conference in Copenhagen in 1938 Blackett agreed to the view that cosmic ray particles were heavier than electrons and he continued the search at Manchester for more mesons.[38]

This search spanned the next decade and more, interrupted by the Second World War, when Nuttall ran the physics department and Blackett returned only two or three times a year to Manchester from his responsibilities in the war office in London.[39] As recalled by Léon Rosenfeld, who succeeded Hartree as Professor of Theoretical Physics, the search for mesons was a far-flung one, using both a huge machine with two magnets and more modest equipment in a corner of the laboratory.[40] In 1947 Occhialini and Cecil F. Powell found Yukawa's particle, the pi-meson or pion, in cosmic rays in Bristol.

That same year Rochester and C. C. Butler found two neutral particles, the so-called V particles which were to figure in a new theory of "strange particles." But for two years they could not find more V particles. Rosenfeld recalled Blackett's attitude: He was not deterred by flops. He stood firm that the initial V particles were not accidents, just tracks coming together, after examining every conceivable interpretation of the tracks. He was certain that they were genuine particles coming from the nucleus and he arranged for the equipment to be put in a laboratory at 2,800 meters on the Jungfrau. The very first day Rochester and Butler had positive results.[41]

By 1947 Blackett had become involved fully in research again at Manchester after a hiatus during the war. His work in operations research during wartime was another application of his craftsmanship in physics, both in theory and in practice, as well as an application of his expertise in administrative management and his conviction that the scientist has responsibility to bring the benefits of science to fellow citizens.

S.S. Schweber and Mike Fortun have discussed the confidence of Blackett and other Anglo-American operations-research scientists in the conformity of rationality with computability, as well as their employment in problems of military strategy of kinds of probabilistic assumptions and mathematical techniques used in particle physics.[42] During this wartime period Blackett also was a member of the MAUD committee, headed by George Thomson, that advised the government to aid development of an atomic bomb in North America.

During the years from 1940-1945 Blackett kept in touch with his Manchester colleagues, including Michael Polanyi, who sometimes felt distanced by the bureaucracy surrounding Blackett at the Admiralty.[43] Polanyi, who was excluded from the war effort because of his foreign [Austrian] citizenship, devoted more and more time to matters of philosophy and social theory. In March of 1941 Polanyi joined with John D. Baker, a lecturer in zoology at Oxford University, and Arthur George Tansley, Oxford's retired Sherardian Professor of Botany, in founding the Society for Freedom in Science. In response to their circular soliciting members, Max Born wrote Blackett from Edinburgh that he could not join the society if freedom of science was coupled to an attack on planning, adding that such a society was condemned to futility if founded on principles that exclude socialist scientists.[44]

By 1947, Polanyi was firmly committed to what might be characterized as a new career in social and epistemological philosophy. He and Blackett disagreed on many matters but continued their friendship. The following year, in 1948, it was announced that Blackett singly would be awarded the Nobel Prize in Physics. Yukawa received it the following year and Powell in 1950.

As letters of congratulations poured into Blackett's office, some of them mentioned not only the Nobel award but also the recent publication and reviews of Blackett's argument against the further development of nuclear weapons, a book that C. H. Waddington praised as a model for a scientific contribution to politics.[45] Harlow Shapley wrote Blackett from the Harvard College Observatory how pleased he was to hear of the Nobel award and that Blackett's book was causing quite a stir in the United States.[46]

But, unlike Polanyi, Blackett had not left science for politics. In May 1947 he announced, firmly if cautiously, a new universal law based on the premise that the rotation of a massive body, including the earth, creates a magnetic field and that this law of magnetism, if broadly confirmed, held the key to a unified theory of gravitational and electromagnetic phenomena. The theory even had historical roots in Manchester, since an earlier and simpler version had been proposed by Arthur Schuster in 1891. The 1947 announcement brought a good deal of instant publicity to Manchester, as science reporters followed Blackett to his home in the suburb of Rusholme and to his laboratory at the University.[47]

During the next five years Blackett discussed his magnetic theory with many colleagues, most of whom, including Niels Bohr, Erwin Schr”dinger, and Albert Einstein, were skeptical. Blackett launched a campaign for confirmation, enlisting astronomers and geophysicists worldwide to aid him with old information and new tests.[48] He contacted engineers in the Royal Aircraft Establishment to help with the design of a precision magnetometer to detect small magnetic fields associated with a spinning disk.[49] The result, in a case study that I am exploring in detail, was Blackett's own announcement in 1952 that his theory was false.

However, by the time he left Manchester for Imperial College in 1953, he was heartened that his work was confirming the newly emerging geophysical theory of continental drift and what would become known as "plate tectonics." [50] One of the last major conferences co-organized by Blackett was in 1965 at the Royal Society. The topic was not particle physics, but continental drift.[51]

The intersecting careers of Patrick Blackett and Michael Polanyi provide a broad window into scientific practice and scientific politics in modern Britain, both within an international setting and within the local setting of Manchester from the 1930s to the 1950s. The intellectual interests of the two men were wide-ranging and their different influences in the practice of physical science and the discourse about science and politics was substantial.

If Polanyi missed out on a single great achievement, he was nonetheless a distinguished scientist whose contributions to the philosophy of science likely are even more widely known than his scientific work. Blackett's scientific career was one of striking achievements in experimental physics, crowned by the Nobel Prize, although his one foray into shaping a revolutionary physical theory failed. He saved this late work from complete discredit because of his open-minded approach to the confirmation of theory and his experimental skill.

Blackett's statements about the practice of scientific method and the nature of scientific knowledge, though less extensive and systematic than Polanyi's, are valuable for their insights and encouragements in the tradition of scientific apprenticeship. They merit comparison with Polanyi's views. Many of the disagreements between the two friends were fundamental to the philosophical and political debate between traditional liberalism and modern socialism. The agreements between them help define the parameters or norms for objectivity and progress in the scientific enterprise. The parallel, but intersecting, scientific lives of Michael Polanyi and Patrick Blackett thus provide a valuable means of studying scientific practice and scientific politics in modern Britain.

Note

I am pleased to acknowledge permissions for consulting the following archival collections: Archives for the History of Quantum Physics, Niels Bohr Library, American Institute of Physics; The Papers of W. Lawrence Bragg, Royal Institution of Great Britain; The Papers of Patrick Maynard Stuart Blackett, Royal Society, London. Research for this paper was supported by National Science Foundation Grant #SBR-9321305, as well as research funding from the University of Oklahoma (George Lynn Cross Research Professor's fund, 1993) and Oregon State University (Thomas Hart and Mary Jones Horning Endowment fund, 1995). The paper was written while I was a By-Fellow, Churchill College, University of Cambridge.

Notes

23. Michael Polanyi, Melvin Calvin, and E. G. Cockbain, `Activation of Hydrogen by Phthalocyanine and Copper Phthalocyanine, I.,' Trans. Faraday Soc., 32 (1936), 1436 ff; Michael Polanyi, Melvin Calvin, and D. D. Eley, `Activation of Hydrogen by Phthalocyanine and Copper Phthalocyanine, II.,' Trans. Faraday Soc., 32 (1936), 1443 ff.

24. Melvin Calvin, `Memories of Michael Polanyi in Manchester,' Tradition and Discovery, 18, #2 (1991-1992), pp. 40-42.

25. Interview of Polanyi with Kuhn, pp. 3-4.

26. Burkhardt, 1954, p. 457.

27. Rudolf Peierls, Bird of Passage. Recollections of a Physicist (Princeton: Princeton University Press, 1985).

28. H. Austin Taylor and Hugh S. Taylor were brothers who took Ph.D. degrees in physical chemistry at Liverpool. M. G. Evans went to Princeton in 1933 to work with Hugh S. Taylor.

29. P.M.S. Blackett, `The Craft of Experimental Physics,' pp. 67-96 in Harold Wright, (ed.), University Studies. Cambridge 1933 (London: Ivor Nicholson and Watson, 1933).

30. P.M.S. Blackett, `The Birth of Nuclear Science,' pp. 380-382, The Listener, March 1954, one of three BBC talks. B.116, Blackett Papers, Royal Society Library. And P.M.S. Blackett, `The Ejection of Protons form Nitrogen Nuclei, Photographed by the Wilson Method,' Proc. R. Soc. Lond, A107 (1925), 349 ff.

31. Interview of P.M.S. Blackett with John L. Heilbron, 17 December 1962, Imperial College, p. 3, Sources for the History of Quantum Physics, Niels Bohr Library, American Institute of Physics. Of the Geiger counter, Blackett reminisced that at that time, "In order to make it work you had to spit on the wire on some Friday evening in Lent."

32. Interview of Carl Anderson with Charles Weiner, 30 June 1966, at Caltech, p. 16, Sources for the History of Quantum Physics, Niels Bohr Library, American Institute of Physics. P.M.S. Blackett and G. P. S. Occhialini, `Photography of Penetrating Corpuscular Radiation,' Nature, 130 (1933), 363 ff. Also P.M.S. Blackett, J. Chadwick and G.P.S. Occhialini, `New Evidence for the Positive Electron,' Nature, 131 (1933), 473 ff; and P.M.S. Blackett, `The Positive Electron,' Nature, 132 (1933), 917; etc. In an interview of James Chadwick with Charles Weiner, 15-20 April 1969, in Cambridge, England, (SHQP, NBL, AIP) Chadwick and Weiner discussed Millikan's showing Anderson's photographs at the Cavendish in 1932 and saying that this was something he could not explain (p. 66).

33. In a letter from James Chadwick to Blackett, 18 November 1971 from Cambridge, he wrote of Rutherford's reluctance to develop nuclear physics in the 1930s. Blackett Papers, J.18, Royal Society Library. Also see Jeffrey Hughes, `Brains in their fingertips': Physics at the Cavendish Laboratory, 1880-1940,' pp. 160-176 in Richard Mason, (ed.), Cambridge Minds (Cambridge: Cambridge University Press, 1995), pp. 172-175.

34. Interview of Otto R. Frisch with Charles Weiner, 3 May 1967, in New York City at AIP, Sources for History of Quantum Physics, Niels Bohr Library, American Institute of Physics, pp. 19-25.

35. Letter from P.M.S. Blackett to Ernest Rutherford, dated 5 July 1937, Blackett Papers, B. 136, Royal Society Library.

36. Lovell, Biog. Mem. FRS, p. 29.

37. Interview of Walter Heitler with John Heilbron, Zurich, 18-19 March 1963, p. 4, SHQP, NBL, AIP.

38. Ibid., and Lovell, Biog. Mem. FRS, p. 30. See P.M.S. Blackett, `The Nature of the Penetrating Component of Cosmic Rays,' Proc. R. Soc. London, A, 165 (1938), 11 ff.

39. Lovell, p. 33 note.

40. Interview of Léon Rosenfeld with Charles Weiner, Copenhagen, 3 September 1968, p. 35, SHQP, NBL, AIP.

41. Interview of Rosenfeld with Charles Weiner, p. 35; Lovell, Biog. Mem. FRS, pp. 35-38; Blackett, `Discoveries from the Big Machines,' The Listener, March 1954, pp. 477-478, Blackett Papers, B.116, Royal Society Library; and Michel Biezunski, Histoire de la physique moderne (Paris: La Découverte, 1993), p. 168. Also see P.M.S. Blackett, `V-Particles and the Cloud Chamber,' Nuovo Cim. (9), 11 (1954), 264 ff.

42. S. S. Schweber and Mike Fortun, `Scientists and the Legacy of World War II: The Case of Operations Research (OR),' Social Studies of Science, 23 (1993), pp. 595-642.

43. Letter from Polanyi to Blackett, 22 September 1942, Blackett Papers, D. 147, Royal Society Library, about Polanyi's inability to get hold of Blackett at the Admiralty while Polanyi was in London a few weeks previously.

44. Letter from Max Born to Blackett, 22 July 1941, from Edinburgh, Blackett Papers, J. 9, Royal Society Library. Also see McGucken, pp. 266-275.

45. P.M.S. Blackett, Military and Political Consequences of Atomic Energy (London: Turnstile Press, 1948). Letter from C. H. Waddington to Blackett, from institute of Animal Genetics, Edinburgh, 6 November 1948.

46. Letter from Harlow Shapley, Harvard College Observatory, 3 December 1948, Blackett Papers, A. 52, Royal Society Library.

47. P. M. S. Blackett, `The Magnetic Field of Massive Rotating Bodies,' Nature, 159 (17 May 1947), pp. 658-666. See `Newton, Einstein - And Now Blackett,' New Review, 29 May 1947, pp. 14-15, Blackett Papers, C. 68, Royal Society Library.

48. Correspondence in Blackett Papers.

49. Letter of 19 June 1947 from Blackett to L. Boddington, Royal Aircraft Establishment, South Farnborough, Hants, 19 June 1947, Blackett Papers, C.11, Royal Society Library; and subsequent correspondence.

50. See Homer E. Le Grand, Drifting Continents and Shifting Theories (Cambridge: Cambridge University Press, 1988) and Walter Sulivan, Continents in Motion. The New Earth Debate, 2nd ed. (New York: American Institute of Physics, 1991).

51. Blackett, with Sir Edward Bullard and S. K. Runcorn, organizers, `Symposium on Continental Drift,' Philosophical Transactions of the Royal Society, A 1088 (1965). Runcorn was a student of Bullard's at Cambridge who was briefly an assistant lecturer in Blackett's department at Manchester before returning to Cambridge. He advocated Bullard's theory of the internal origin of the earth's magnetism against Blackett's "fundamental" theory. See S. K. Runcorn, `[Contribution to] Memorial Meeting for Lord Blackett,' Notes and Records of the Royal Society of London, 29 (1975), pp. 156-158.