I am grateful to Professor Derek Forrest for advice and encouragement; to Professor W. F. Bynum and anonymous referees for their constructive comments on earlier drafts; to Dr William F. Brewer for some helpful correspondence; and especially to Dr Gillian Furlong and her assistants at the Manuscripts Room in the Library of University College London. Extracts from the unpublished Galton Papers are printed by permission of University College.

¹ See Boring, Edwin G., A History of Experimental Psychology, 2nd edn, New York, 1957, 482–8.Google Scholar

² Most of Galton's work in this period is conveniently reprinted or summarized in his book Inquiries into Human Faculty, London, 1883 (cited here from the Everyman's Library edition, 1907)Google Scholar. To this should be added two slightly later articles: ‘Free-will – observations and inferences’, Mind (1884), 9, 406–13Google Scholar, and ‘Measurement of character’, Fortnightly Review (1884), 36, 179–85Google Scholar. For an overview of Galton's psychological work see relevant chapters in Pearson, Karl, The Life, Letters and Labours of Francis Galton, 3 vols, in 4, Cambridge, 1914–1930Google Scholar; Forrest, D. W., Francis Calton: The Life and Work of a Victorian Genius, London, 1974Google Scholar; or Fancher, Raymond E., Pioneers of Psychology, 2nd edn, New York, 1990.Google Scholar

³ A notable exception is Derek Forrest's detailed analysis of Galton's ‘word association’ experiments: Forrest, , op. cit. (2), 144–8Google Scholar. Fancher, Raymond E.'s ‘Biographical origins of Francis Galton's psychology’, Isis (1983), 74, 227–33CrossRefGoogle ScholarPubMed, and ‘Francis Galton's African ethnography and its role in the development of his psychology’, BJHS (1983), 16, 67–79Google Scholar, are concerned with the personal origins of Galton's hereditarian beliefs. The recent symposium volume, Sir Francis Galton, FRS: The Legacy of His ideas (ed. Keynes, Milo), London, 1993CrossRefGoogle Scholar, covers several neglected areas of Galton's career but does not include a historical study of his work in psychology.

⁴ Galton, 's main studies of mental imagery are: ‘Visualised numerals’, Nature (1880), 21, 252–6CrossRefGoogle Scholar; ‘Visualised numerals’, Journal of the Anthropological Institute (1880), 10, 85–102Google Scholar; ‘Statistics of mental imagery’, Mind (1880), 5, 301–18Google Scholar; ‘Mental imagery’, Fortnightly Review (1880), 28 (new series), 312–24Google Scholar; ‘The visions of sane persons’, Proceedings of the Royal Institution of Great Britain (1881), 9, 644–55Google Scholar; and Inquiries into Human Faculty, op. cit. (2), 57–128Google Scholar, which summarizes the earlier work but also contains a good deal of previously unpublished material.

⁵ Bynum, W. F., ‘The historical Galton’Google Scholar, in Keynes, , op. cit (3), 38.Google Scholar

⁶ Galton, , ‘Statistics of mental imagery’, op. cit. (4), 304Google Scholar. For a valuable study of Gallon's previous contacts in the scientific community, see Hilts, Victor: ‘A guide to Francis Gallon's English men of science’. Transactions of the American Philosophical Society (1975), 65, part 5.CrossRefGoogle Scholar

⁷ A catalogue is given in the List of the Galton Papers in the Manuscripts Room, the Library, University College London, compiled by Merrington, M. and Golden, J., University College London, 1978Google Scholar. Items from the collection are cited here as ‘GP’ followed by the reference number in Merringlon and Golden.

⁸ Galton, F., ‘Typical laws of heredity’, Proceedings of the Royal Institution of Great Britain (1877), 8, 282–301.Google Scholar

⁹ For accounts of this work see Cowan, Ruth S., ‘Nature and nurture: the interplay of biology and politics in the work of Francis Galton’, Studies in the History of Biology (1977), 1, 133–208Google ScholarPubMed; MacKenzie, Donald A., Statistics in Britain 1865–1930, Edinburgh, 1981, ch. 3Google Scholar; Porter, Theodore M., The Rise of Statistical Thinking 1820–1900, Princeton, 1986, ch. 5Google Scholar; and Stigler, Stephen M., The History of Statistics, Harvard, 1986, ch. 8.Google Scholar

¹⁰ I do not wish io exaggerate the sharpness of Galton's change of direction. Some of his previous work on heredity had involved psychological issues, while conversely Galton himself was alert to the implications of his more narrowly psychological researches for the study of heredilary characteristics; see for example Galton, , Inquiries into Human Faculty, op. cit. (2), 1, 69, 100, 107Google Scholar. Nevertheless, there is a clear difference of emphasis to be explained.

¹¹ British Association for the Advancement of Science (BAAS) Report for 1885, 1207.Google Scholar

¹² Pearson, , op. cit. (2), iiiA, 11Google Scholar; Forrest, , op. cit. (2), 188Google Scholar; cf. Cowan, Ruth S., ‘Francis Galton's statistical ideas: the influence of eugenics’, Isis (1972), 63, 521.CrossRefGoogle ScholarPubMed

¹³ BAAS Report for 1877, 94–100.Google Scholar

¹⁴ See the comments of Bynum, , op. cit. (5), 36Google Scholar, on the need for a fresh biography and possible sources of information.

¹⁵ Bynum, , op. cit. (5), 41Google Scholar, cf. Pearson, , op. cit. (2), ii, 12.Google Scholar

¹⁶ Bynum, , op. cit. (5), 41Google Scholar; Pearson, , op. cit. (2), ii, 12.Google Scholar

¹⁷ In the small portion of the Galton Papers I have examined there are reading notes, in some cases very full, on Gall, Spurzheim, Quatrefages, Virchow, Claude Bernard, Maudsley, Malthus, Prosper Lucas, Professor Benedict of Vienna, S. B. Thornton and Prosper Despine.

¹⁸ For Fechner's work see Boring, , op. cit. (1), ch. 14Google Scholar, or Fancher, , op. cit. (2), ch. 4Google Scholar. Fechner's work was introduced to British readers by Sully, James in an unsigned review article, ‘Recent experiments with the senses’, Westminster Review (1872), 165–98Google Scholar, and his book Sensation and Intuition, London, 1874Google Scholar. Sully was later one of Galton's ‘100’ and worked with him in a study of the senses and memory of asylum inmates: see Galton, 's ‘Supplementary notes on prehension in idiots’, Mind (1886), 12, 79–82.Google Scholar

¹⁹ Letter of 4 June 1875 to Mrs Hertz; see Pearson, , op. cit. (2), iiiB, 464.Google Scholar

²⁰ James, William, Principles of Psychology, 2 vols., 1890 (Dover Publications reprint, 1950), ii, 51.Google Scholar

²¹ Notably in Galton, F., ‘Composite portraits’, Nature (1878), 18, 97Google Scholar; ‘Psychometric facts’, Nineteenth Century (1879), 5, 425–32Google Scholar; ‘Generic images’, Proceedings of the Royal Institution of Great Britain (1879), 9, 162–6Google Scholar; and ‘Generic images’, Nineteenth Century (1879), 6, 158–60.Google Scholar

²² Galton, , Inquiries into Human Faculty, op. cit. (2), 57.Google Scholar

²³ For example, Maudsley, H.: The Physiology of Mind, London, 1876, 293Google Scholar; Carpenter, W. B., Mental Physiology, 3rd edn, London, 1875, 546–47.Google Scholar

²⁴ Fechner, , Elemente der Psychophysik, ch. 44Google Scholar, cited by James, , op. cit. (20), ii, 51Google Scholar. I have not been able to consult Fechner's original text on this point.

²⁵ The Times, 3 09 1880Google Scholar. Much of Galton's work encountered a mixed response from his contemporaries; for a recent study see Gökyigit, Emel Aileen, ‘The reception of Francis Galton's Hereditary Genius in the Victorian periodical press’, Journal of the History of Biology (1994), 27, 215–40.CrossRefGoogle ScholarPubMed

²⁶ GP 152/1, note headed ‘Rough draft’.

²⁷ Galton, , ‘Visualised numerals’, Journal of the Anthropological Institute, op. cit. (4), 86.Google Scholar

²⁸ Letter from Bidder, G., 14 04 1879Google Scholar, GP 152/6A. Galton had written to Bidder enquiring about his visualizing powers following correspondence in the Spectator (12 1878 – 02 1879)Google Scholar about his father.

²⁹ For a recent study strikingly confirming most of Galton's findings, see Seron, X. et al. , ‘Images of numbers, or “When 98 is upper left and 6 sky blue”’, in Numerical Cognition (ed. Dehaene, Stanislaus), Oxford, 1993.Google Scholar

³⁰ Synaesthesia is most fully discussed in the chapter on ‘Colour associations’ in Galton, , Inquiries into Human Faculty, op. cit. (2), 105–12.Google Scholar

³¹ Galton, , Inquiries into Human Faculty op. cit. (2), Appendix E.Google Scholar

³² GP 152/1–7.

³³ Replies to the questionnaire are mainly in GP 152/2 and 152/3.

³⁴ Darwin's reply is preserved with other Darwin correspondence in GP 39/E and printed in Pearson, , op. cit. (2), ii, 194–6.Google Scholar

³⁵ Hawtrey's reply is attached to a letter of 27 March 1880 from H. G. Willink in GP 152/6B.

³⁶ One is an anonymous reply on which Gallon noted in pencil ‘A lady?’, another is from a teenaged boy, and the third is a reply to a special version of the questionnaire apparently designed for students of mechanical drawing. I have found only a single response to this version.

³⁷ GP 152/2 A.

³⁸ GP 152/3.

³⁹ Galton, , ‘Statistics of mental imagery’, op. cit. (4), passim.Google Scholar

⁴⁰ Galton, , ‘Visualised numerals’, Nature, op. cit. (4), 252.Google Scholar

⁴¹ GP 152/1.

⁴² Proceedings of the Birmingham Philosophical Society (1879), 2, 26–9.Google Scholar

⁴³ For Galton's collaborations with Du Cane, see Galton, 's Memories of My Life, London, 1908, 259–61.Google Scholar

⁴⁴ Galton, , op. cit. (43), 304.Google Scholar

⁴⁵ Letter of 17 January 1880 from McAlister, GP 152/6B.

⁴⁶ For Galton's friendship with Croom Robertson see Galton, , op. cit. (43), 267.Google Scholar

⁴⁷ Galton, , ‘Visualised numerals’, Nature, op. cit. (4).Google Scholar

⁴⁸ Galton, , ‘Statistics of mental imagery’, op. cit. (4), 303.Google Scholar

⁴⁹ Letter of 2 February 1880 from Henry Yule, GP 152/4.

⁵⁰ Letter of 14 November 1879 from Gerald Yeo, GP 152/6B.

⁵¹ In GP 152/6B.

⁵² See an undated letter from Shute to Galton, GP 152/6B.

⁵³ Questionnaire returned by Professor John Marshall, FRS, GP 152/2B.

⁵⁴ GP 152/7, notebook titled ‘List of names’.

⁵⁵ Published in Nature (1887), 36.Google Scholar

⁵⁶ Galton, , ‘Visualised numerals’, Nature, op. cit. (4)Google Scholar; ‘Visualised numerals’, Journal of the Anthropological Institute, op. cit. (4).Google Scholar

⁵⁷ Galton, , ‘Mental imagery’, op. cit. (4), 312.Google Scholar

⁵⁸ Galton, , ‘Statistics of mental imagery’, op. cit. (4) 304.Google Scholar

⁵⁹ Galton, , ‘Statistics of mental imagery’, op. cit. (4), 302.Google Scholar

⁶⁰ Thomson, G., Instinct, Intelligence and Character, London, 1924, 93.Google Scholar

⁶¹ In his autobiographical Memories of My Life, op. cit. (43), 270–1Google Scholar, Galton describes the negative response of his scientific colleagues, but refers only to number forms in this context. Cf. ‘Visualised numerals’, Journal of the Anthropological Institute, op. cit. (4), 85.Google Scholar

⁶² Report in The Guardian, London, 17 07 1991Google Scholar, and personal communication. Dr Brewer informs me that the Guardian report does not accurately represent his views.

⁶³ Galton actually says that ‘the adult males are not very dissimilar to them; but the latter [the adults] do not seem to form so regular a series as the boys’ (‘Statistics of mental imagery’, op. cit. (4), 312).Google Scholar

⁶⁴ Galton, , ‘Statistics of mental imagery’, op. cit. (4), 312Google Scholar; cf. Inquiries into Human Faculty, op. cit. (2), 60.Google Scholar

⁶⁵ See especially Galton, , ‘Statistics of mental imagery’, op. cit. (4), 301–2.Google Scholar

⁶⁶ The method was first explained in Galton, F., ‘Statistics by intercomparison’, Philosophical Magazine (1875), 49, 33–46Google Scholar. Its application to Galton's mental imagery data is described most fully in ‘Statistics of mental imagery’, op. cit. (4), 306–12.Google Scholar

⁶⁷ The relevant working papers are mainly in GP 152/1. Galton's ranking runs from 1, the strongest case of imagery, to 100, the weakest. The precise ranking is known only for 36 cases, but the others can be placed in classes of ‘vividness’. Different rankings were constructed for ‘colour’ and other aspects of imagery, but the information on these is less complete.

⁶⁸ Galton, F., English Men of Science, their Nature and Nurture, London, 1874, 2–6.Google Scholar

⁶⁹ Taking the average of the available places in the ranking where the precise place is not known. The average for the FRS cases must in any event be between 58.8 and 68.2. It makes no material difference whether we count Marshall or Piazzi Smyth for this purpose.

⁷⁰ In fact, the estimated average is slightly depressed.

⁷¹ In his paper on ‘Generic images’, Proceedings of the Royal Institution of Great Britain, op. cit. (21), 169.Google Scholar

⁷² In GP 152/1.

⁷³ The revised version of the questionnaire has no separate question on ‘completeness’; as this was a useful question the change is regrettable.

⁷⁴ Probably one of the many daughters of Sir John Herschel; her address is that of the Herschel family home at Collingwood.

⁷⁵ Letter of 8 August 1880 from Isabella Herschel, GP 152/5A.

⁷⁶ Galton, , Inquiries into Human Faculty, op. cit. (2), 66Google Scholar. This important qualification does not seem to have been noticed in the subsequent literature.

⁷⁷ Questionnaire completed by General Sir Henry Lefroy, GP 152/2B.

⁷⁸ Questionnaire completed by Charles Piazzi Smyth, GP 152/2B.

⁷⁹ See Galton, , ‘Statistics of mental imagery’, op. cit. (4), 306.Google Scholar

⁸⁰ Galton applied this precaution both to ‘number forms’ and to ‘colour associations’: see Inquiries into Human Faculty, op. cit. (2), 81, 100, 106.Google Scholar

⁸¹ Questionnaire returned by John Marshall, FRS, GP 152/2B.

⁸² Letter of 7 December 1879 from John Ball, FRS, GP 152/6A.

⁸³ Questionnaire returned by James Crichton Browne, GP 152/2B.

⁸⁴ Questionnaire returned by Major John Herschel, GP 152/2B.

⁸⁵ Letter of 21 February 1880 from Major John Herschel, GP 152/4.

⁸⁶ I do not suggest that Galton's correspondents were alone in this attitude; for previous criticism of introspective methods see for example Maudsley, , op. cit. (23), ch. 1.Google Scholar

⁸⁷ See especially Inquiries into Human Faculty, op. cit. (2), 78–9Google Scholar. Galton believed that the power of visualization could be greatly enhanced by practice, despite claiming a hereditary basis for individual differences in imagery. His views on the role of ‘nature and nurture’, at least in this case, were more complex than is sometimes supposed.

⁸⁸ Letters from Antoine Abbadie, Professor Dajnist, Gustaf Eisen, A. Achard and Dr James Key, all in GP 152/6A, and completed questionnaire returned by Professor S. Alfitt of Allahabad, GP 152/2B.

⁸⁹ Letter from H. F. Osborn in GP 152/6B, and summary of data in GP 152/1.

⁹⁰ Most fully reported in Inquiries into Human Faculty, op. cit. (2), 105–28Google Scholar. Some of the more striking cases are shown in illustrations. It is a pity that the remarkable images of the novelist Mrs Haweis were not reproduced; her own drawings are, however, preserved in GP 152/8.

⁹¹ This judgement might admittedly require amendment if more of Galton's side of his correspondence were available.

⁹² Galton did, however, later suggest methods of measuring the ‘strength of the imagination’ more objectively by experimentally determining the point at which different individuals confused a faint perceptual image with a mental image: see Galton, F., ‘The just-perceptible difference’, Proceedings of the Royal Institution of Great Britain (1893), 14, 255–7.Google Scholar

⁹³ The problem is not, however, an easy one: for some modern discussions see, for example, Richardson, Alan, Mental Imagery, London, 1969CrossRefGoogle Scholar; or Kosslyn, Stephen M., Image and Mind, Cambridge, Mass., 1980.Google Scholar

⁹⁴ Compare the remarks of Pearson, , op. cit. (2), ii, 282.Google Scholar