Hostname: page-component-8448b6f56d-jr42d Total loading time: 0 Render date: 2024-04-16T11:53:51.943Z Has data issue: false hasContentIssue false

The discovery of a vocation: Darwin's early geology

Published online by Cambridge University Press:  05 January 2009

James A. Secord
Affiliation:
History of Science and Technology Group, Sheffield Building, Imperial College, London SW7 2AZ, UK.

Extract

When HMS Beagle made its first landfall in January 1832, the twenty-two-year-old Charles Darwin set about taking detailed notes on geology. He was soon planning a volume on the geological structure of the places visited, and letters to his sisters confirm that he identified himself as a ‘geologist’. For a young gentleman of his class and income, this was a remarkable thing to do. Darwin's conversion to evolution by selection has been examined so intensively that it is easy to forget that the most extraordinary decision he ever made was to devote his life to the study of the natural world by becoming a geologist. It is only slightly less astonishing that he should have decided to align his work with Charles Lyell's controversial programme of geological reform, which had almost no followers in England.

Type
Research Article
Copyright
Copyright © British Society for the History of Science 1991

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1 General surveys of Darwin's geological work include: Judd, J. W., ‘Darwin and geology’, in Darwin and Modern Science (ed. Seward, A. C.), Cambridge, 1909, pp. 337–84Google Scholar; the introductory essays by Judd in Darwin, C., On the Structure and Distribution of Coral Reefs: Also Geological Observations on the Volcanic Islands and Parts of South America Visited during the Voyage of H. M. S. Beagle (ed. Judd, J. W.), London, n. d.Google Scholar; Herbert, S., ‘The logic of Darwin's discovery’, Ph.D. dissertation, Brandeis University, 1968Google Scholar; idem., ‘Darwin as a geologist’, Scientific American, (1986), 254, no. 5, pp. 116–23Google Scholar; Rhodes, F. H. T., pp. 193229Google Scholar, this volume.

2 Of course, there were many more skilled and experienced geologists in 1832, but few who were so young.

3 Barlow, N. (ed.), The Autobiography of Charles Darwin, London, 1958, pp. 52–3Google Scholar. For a general discussion of Darwin's Edinburgh years, see Ashworth, J. H., ‘Charles Darwin as a student in Edinburgh, 1825–1827’, Proceedings of the Royal Society of Edinburgh, (19341935), 55, pp. 97113.CrossRefGoogle Scholar

4 Darwin, C. to Hooker, J. D., 24 [05 1854]Google Scholar, in Burkhardt, F. and Smith, S. (eds.), The Correspondence of Charles Darwin, Cambridge, 1985–, v, p. 195.Google Scholar

5 These and other comments on Jameson's lectures can be found in Eyles, V. A., ‘Robert Jameson and the Royal Scottish Museum’, Discovery, (1954), 15, pp. 155–62, esp. p. 159Google Scholar; see also Flinn, D., ‘James Hutton and Robert Jameson’, Scottish Journal of Geology, (1980), 16, pp. 251–8CrossRefGoogle Scholar. Jameson's course in the wider context of the University is clearly set out in Morrell, J. B., ‘Science and Scottish University reform: Edinburgh in 1826’, BJHS, (1972), 6, pp. 3958, esp. pp. 4851.CrossRefGoogle ScholarPubMed

6 ‘Darwin in Edinburgh. II’, St. James's Gazette, (17 02 1888), 16, no. 2404, p. 7Google Scholar. The anonymous author of this article notes that Darwin did not register for this class and probably joined it late in the session, perhaps with the encouragement of his friends in the Plinian and other student natural history societies. Any lectures he would have missed involved meteorology and hydrography.

7 Barlow, (ed.), op. cit. (3), p. 45.Google Scholar

8 Jameson, R., Manual of Mineralogy: Containing an Account of Simple Minerals, and also a Description and Arrangement of Mountain Rocks, Edinburgh, 1821, pp. 88–9CrossRefGoogle Scholar; copy in Darwin Archive, CUL. I am grateful to Mario di Gregorio for providing a copy of his transcription of these remarks, published in M. A. Di Gregorio with the assistance of Gill, N. W., Charles Darwin's Marginalia, New York, 1990, i, cols. 432–40.Google Scholar

9 Ibid., p. 466.

10 Ibid., pp. 421, 447, 452; for Jameson's encouragement of debate, see Secord, J. A., ‘Edinburgh Lamarckians: Robert Jameson and Robert E. Grant’, Journal of the History of Biology, (1991), 24, pp. 118.Google Scholar

11 Ibid., pp. 382, 341–2. For the emphasis of Wernerian geology on classification and order, see Laudan, R., From Mineralogy to Geology: The Foundations of a Science, Chicago, 1987, esp. pp. 138–79CrossRefGoogle Scholar; and Greene, M. T., Geology in the Nineteenth Century: Changing Views of a Changing World, Ithaca, NY, 1982, pp. 1968.Google Scholar

12 Secord, , op. cit. (10).Google Scholar

13 Evidence, Oral and Documentary, Taken and Received by the Commissioners… for Visiting the Universities of Scotland: The University of Edinburgh, Parliamentary Papers, 35, (1837), p. 145Google Scholar. Jameson's deployment of this approach in the context of Edinburgh lecturing is effectively dealt with in Porter, R., The Making of Geology: Earth Science in Britain, 1660–1815, Cambridge, 1977, pp. 149–56.Google Scholar

14 Sloan, P. R., ‘Darwin's invertebrate program, 1826–1836: preconditions for transformism’, in The Darwinian Heritage (ed. Kohn, D.), Princeton, 1985, pp. 71120Google Scholar; and ‘Darwin, vital matter, and the transformation of species’, Journal of the History of Biology, (1986), 19, pp. 369445Google Scholar. M. J. S. Hodge has emphasized the importance of Edinburgh for Darwin's ‘zoonomical’ programme; see his ‘Darwin as a lifelong generation theorist’, in Kohn (ed.), ibid., pp. 207–43.

15 Barlow, (ed.), op. cit. (3), p. 53Google Scholar. The fruitful nature of Wernerian research is emphasized in Laudan, , op. cit. (11)Google Scholar, and in Ospovat, A. M., ‘Reflections on A. G. Werner's “Kurze Klassification”’, in Toward a History of Geology (ed. Schneer, C. J.), Cambridge, Mass., 1969, pp. 242–58Google Scholar. It is interesting to note that Jameson apparently played no part in the campaign to save Mutton's geological sections at Salisbury Crags from destruction by quarrying. The fight was led by Sir James Hall and Thomas Charles Hope, as explained in Gray, W. Forbes, ‘The quarrying of Salisbury Crags’, The Book of the Old Edinburgh Club, (1932), 18, pp. 181210.Google Scholar

16 For Hope as a teacher, see Morrell, , op. cit. (5), esp. pp. 53–5Google Scholar; ‘Practical chemistry in the University of Edinburgh’, Ambix, (1969), pp. 6680Google Scholar; and Traill, T. S., ‘Memoir of Dr. Thomas Charles Hope, Late Professor of Chemistry in the University of Edinburgh’, Transactions of the Royal Society of Edinburgh, (1849), 16, pp. 419–34.CrossRefGoogle Scholar

17 Bennett, E. W., ‘Outlines of a course of lectures on chemistry delivered by Dr Hope – in the University of Edinburgh in the Session of 1822 & 23’, Edinburgh University Library: Ms Gen. 746D, fols. 204–5Google Scholar. Darwin seems to have followed Hope's advice to purchase the works of Jameson and Playfair; his copy of the former author's Treatise on the External, Chemical, and Physical Characters of Minerals, 2nd edn, Edinburgh, 1816Google Scholar, is dated ‘Feb. 13th 1826’. His copy of Playfair, J., Illustrations of the Huttonian Theory of the Earth, Edinburgh, 1802CrossRefGoogle Scholar, is undated, but is signed ‘Charles Darwin’ in the same large hand found in many of his pre-Beagle books.

18 Edinburgh University Library: Ms. Gen. 7460, fols. 250–1.

19 Ibid., fols. 1, 10, 13. It is worth noting that Hope, like Hall, differed from Hutton in his willingness to admit to evidence for major catastrophes in Earth history. In 1810, for example, Hope claimed that the progress of erosion ‘must have been greatly accelerated by the Deluge’. Whether he still held this opinion in 1826 is not known. [Archibald] Alison, ‘Notes on chemistry from Dr Hopes Lectures’, Edinburgh University Library: Ms. Gen. 1399, iv, p. 21.

20 Morrell, , op. cit. (5).Google Scholar

21 Evidence, op. cit. (13), p. 145.Google Scholar

22 As evidenced by a letter of 1844, when he claimed not to know the editor of the Edinburgh New Philosophical Journal: Darwin, C. to von Morlot, A., 9 08 [1844]Google Scholar, Burkhardt, and Smith, (eds.), op. cit. (4), iii, p. 51Google Scholar. For Hope, see Darwin, C. to Darwin, Caroline, 6 01 1826Google Scholar, in ibid., i, p. 25. For the family links, see Shepperson, G., ‘The intellectual background of Charles Darwin's student years at Edinburgh’, in Darwinism and the Study of Society: A Centenary Symposium (ed. Banton, M.), London, 1961, pp. 1735.Google Scholar

23 Morrell, , op. cit. (16)Google Scholar; Jameson, L., ‘Biographical memoir of the late Professor Jameson’, Edinburgh New Philosophical Journal, (1854), 57, pp. 149.Google Scholar

24 Thackray, A., ‘Natural knowledgein cultural context:the Manchester model’, American Historical Review, (1974), 79, pp. 672709CrossRefGoogle Scholar; Davidoff, L. and Hall, C., Family Fortunes: Men and Women of the English Middle Class, 1780–1850, London, 1987.Google Scholar

25 Schweber, S. S., ‘The wider British context in Darwin's theorizing’, in Kohn (ed.), op. cit. (14), pp. 3569, esp. pp. 3947.Google Scholar

26 Herbert, S., pp. 161, 162Google Scholar, this volume. Darwin, E., The Botanic Garden; A Poem, in Two Parts, London, 1791Google Scholar, ‘Section of the Earth’ facing p. 67 of the ‘Additional Notes’ to pt i, The Economy of Vegetation. For the ‘Huttonian Earth-machine’, see Davies, G. L., The Earth in Decay: A History of British Geomorphology, 1578–1878, New York, 1969, pp. 154–99.Google Scholar

27 Barlow, (ed.), op. cit. (3), pp. 5969, 67–9Google Scholar; Burkhardt, and Smith, (eds.), op. cit. (4), i, pp. 539–40Google Scholar. For the model of the clergyman naturalist, see Moore, J. R., ‘Darwin of Down: the evolutionist as squarson-naturalist’Google Scholar, in Kohn, (ed.), op. cit. (14), pp. 435–81.Google Scholar

28 Rodwell, to Darwin, F., 8 07 1832, DAR 112, fol. 94vGoogle Scholar; for Herbert's reminiscences, see DAR 112, fols. 67–68. The issue is raised in Burkhardt, and Smith, (eds.), op. cit. (4), i, p. 125.Google Scholar

29 Darwin, C. to Darwin, Caroline, [28 04 1831]Google Scholar, Burkhardt, and Smith, (eds.), op. cit. (4), i, p. 122.Google Scholar

30 Darwin, C. to Henslow, J. S., [11 07 1831]Google Scholar, in Burkhardt, and Smith, (eds.), op. cit. (4), i, p. 125Google Scholar. Darwin described this type of clinometer in his essay on ‘Geology’ in Herschel, J. F. W.'s Manual of Scientific Enquiry, London, 1849Google Scholar; reprinted in The Collected Papers of Charles Darwin (ed. Barrett, P. H.), 2 vols., Chicago, 1977, i, 227–50, at p. 229.Google Scholar

31 Barlow, (ed.), op. cit. (3), pp. 68–9Google Scholar. Several pages of early field notes from the area around Llanmynach (a village sixteen miles northwest of Shrewsbury) may date from this time, or may have been made during the first stage of the tour with Sedgwick; see DAR 5.C4, fols. 1–4.

32 Compare Darwin, C. to Henslow, J. S., [11 07 1831]Google Scholar, with Darwin, C. to Fox, W. D., [9 07 1831]Google Scholar, in Burkhardt, and Smith, (eds.), op. cit. (4), i, pp. 124–5.Google Scholar

33 For tacit knowledge, see Polanyi, M., Personal Knowledge: Towards a Post-critical Philosophy, London, 1958Google Scholar; idem, The Tacit Dimension, Garden City, New York, 1966Google Scholar; Collins, H. M., Changing Order: Replication and Induction in Scientific Practice, London, 1985Google Scholar, and Ravetz, J. R., Scientific Knowledge and its Social Problems, Oxford, 1971, pp. 75108.Google Scholar

34 Rudwick, M. J. S., ‘Charles Darwin in London: the integration of public and private science’, Isis, (1982), 73, pp. 186206, at p. 193Google Scholar. The transformation was, however, not in Darwin's ascribed status (as Rudwick suggests), but in his self-image. For the quotation, see Darwin, C. to Whitley, C. T., [12 07 1831]Google Scholar, in Burkhardt, and Smith, (eds.), op. cit. (4), vii, p. 466.Google Scholar

35 Barlow, (ed.), op. cit. (3), pp. 6970Google Scholar: I told Sedgwick of the fact, and he at once said (no doubt truly) that it must have been thrown away by someone into the pit; but then added, if really embedded there it would overthrow all that we know about the superficial deposits of the midland counties… But I was then utterly astonished at Sedgwick not being delighted at so wonderful a fact as a tropical shell being found near the surface in the middle of England.’

36 The notes (DAR 5, fols. 5–16) are transcribed in Barrett, P. H., ‘The Sedgwick-Darwin geological tour of North Wales’, Proceedings of the American Philosophical Society, (1974), 118, pp. 146–64Google Scholar. Sedgwick's maps and notebooks, including a typed transcription by O. T. Jones, are in the Sedgwick Museum, University of Cambridge.

37 Greenough, G. B., A Geological Map of England and Wales, London, 1820Google Scholar. A copy of a reduced version published by J. Gardner in 1826, in the map collection of Cambridge University Library, is said to have belonged to Darwin.

For the role of Greenough's map, see Rudwick, M. J. S., ‘The foundation of the Geological Society of London: its scheme for co-operative research and its struggle for independence’, BJHS, (1963), 1, pp. 234–72CrossRefGoogle Scholar, and the alternative view expressed in Laudan, R., ‘Ideas and organizations in British geology: a case study in institutional history’, Isis, (1977), 68, pp. 527–38CrossRefGoogle Scholar. For Sedgwick's researches, see Secord, J. A., Controversy in Victorian Geology: The Cambrian-Silurian Dispute, Princeton, 1986, esp. pp. 4750Google Scholar; for the work of his predecessors, see Torrens, H., ‘Arthur Aikin's mineralogical survey of Shropshire, 1796–1816, and the contemporary audience for geological publications’, BJHS, (1983), 16, pp. 111–53CrossRefGoogle Scholar, and Hailstone, J. to Sedgwick, A., 6 06 1831Google Scholar, Cambridge University Library, Add. ms 7652.IA.56.

38 Barrett, , op. cit. (36), p. 157Google Scholar; Sedgwick, A., entry for 8 08 1831Google Scholar. For a good contemporary account of the caves at Plas-yn-Cefn, see Stanley, E., ‘Memoir on a cave at Cefn in Denbigshire’, Edinburgh New Philosophical Journal, (1833), 14, pp. 4053Google Scholar, based on fieldwork in the first three months of 1832. Stanley (p. 41) emphasizes the ease of finding vertebrate fossils at Cefn.

39 Sedgwick, A., entries for 6–8 08 1831Google Scholar, Journal no. XXI; Barrett, , op. cit. 36, p. 156Google Scholar. Also helpful is Sedgwick's contemperary account of the main results of the tour with Darwin: Sedgwick, to Murchison, , 13 09 1831Google Scholar, in Clark, J. W. and Hughes, T. M., The Life and Letters of Adam Sedgwick, 2 vols., Cambridge, 1890, i, pp. 377–9, at p. 378.Google Scholar

40 Barrett, , op. cit. (36), pp. 157–8.Google Scholar

41 Barrett, , op. cit. (36), p. 158Google Scholar. For the prevalence of this interpretation of valley formation, see Davies, , op. cit. (26), p. 241Google Scholar. Darwin recalled Sedgwick's reaction in Darwin, C. to Hughes, T. M., 24 05 1875Google Scholar, in Clark, and Hughes, , op. cit. (39), i, pp. 380–1.Google Scholar

42 Barlow, (ed.), op. cit. (3), pp. 6970Google Scholar; see note 35 above.

43 Secord, , op. cit. (37), pp. 5768Google Scholar; Smith, C., ‘Geologists and mathematicians: the rise of physical geology’, in Wranglers and Physicists: Studies on Cambridge Physics in the Nineteenth Century (ed. Harman, P.), Manchester, 1985, pp. 4983.Google Scholar

44 Barrett, , op. cit. (36), p. 159Google Scholar. Darwin's research on this topic on the voyage is summarized in his Geological Observations on South America, London, 1846.Google Scholar

45 Darwin, C. to Henslow, J. S., 16 06 1832Google Scholar, in Burkchardt, and Smith, (eds.), op. cit. (4), i, p. 238Google Scholar; see also Darwin, to Henslow, , 11 04 1833Google Scholar, ibid., p. 308.

46 Sedgwick, A. to Darwin, C., 4 09 1831, op. cit. (4), i, p. 137Google Scholar. For problems that could result from collecting loose specimens, see Secord, , op. cit. (37), pp. 250–1.Google Scholar

47 Darwin, C. to Henslow, J. S., 18 05 1832Google Scholar, in Burkhardt, and Smith, (eds.), op. cit. (4), i, p. 236–9.Google Scholar

48 Keynes, R. D. (ed.), Charles Darwin's Beagle Diary, Cambridge, 1988, pp. 67Google Scholar, entries for 12–13 November 1831. The Admiralty instructions for the voyage – which contain much on geology – are in Narrative of the Surveying Voyages of His Majesty's Ships Adventure and Beagle, Between the Years 1826 and 1836, Describing their Examination of the Southern Shores of South America, and the Beagle's Circumnavigation of the Globe, 3 vols., London, 1839, ii, pp. 2440Google Scholar, and are conveniently available in Darwin, C., Voyage of the Beagle (ed. Browne, J. and Neve, M.), London, 1989, pp. 378–99.Google Scholar

49 These and other books carried on the Beagle are listed in Burkhardt and Smith, (eds.), op. cit. (4), i, pp. 553–66.Google Scholar

50 Laudan, , op. cit. (11), esp. pp. 180–97Google Scholar gives the best available summary of the kind of causal geology that dominated European geology in the 1820s, and shaped much of Darwin's own work. The special importance of Herschel – particularly in relation to the reading of Lyell – is emphasized in Ruse, M., ‘Darwin's debt to philosophy: an examination of the influence of the philosophical ideas of John F. W. Herschel and William Whewell on the development of Charles Darwin's theory of evolution’, Studies in the History and Philosophy of Science, (1975), 6, pp. 159–81.CrossRefGoogle Scholar

51 Darwin's pre-Lyellian geology is presented as an essentially Scriptural science in the classic discussion in , H. E. and Gruber, V., ‘The eye of reason: Darwin's development during the Beagle voyage’, Isis, (1962), 53, pp. 186200CrossRefGoogle Scholar. For a detailed account of Darwin's attitude towards the diluvium, see Herbert, , op. cit. (26).Google Scholar

52 Darwin's later use of Lyell has of course been explored in considerable detail. Besides the general sources cited in note 1, see esp. Herbert, S., ‘Les divergences entre Darwin et Lyell sur quelques questions géologiques’, in De Darwin au Darwinism (ed. Conry, Y.), Paris, 1983, pp. 6976Google Scholar; Hodge, M. J. S., ‘Darwin and the laws of the animate part of the terrestrial system (1835–1837): on the Lyellian origins of his zoonomical explanatory program’, Studies in History of Biology, (1983), 6, pp. 1106Google Scholar; Rudwick, M. J. S., ‘Darwin and Glen Roy: a “great failure” in scientific method?’, Studies in History and Philosophy of Science, (1974), 5, pp. 97185CrossRefGoogle Scholar; Stoddart, D. R., ‘Darwin, Lyell, and the geological significance of coral reefs’, BJHS, (1976), 9, pp. 199218.CrossRefGoogle Scholar

53 Barlow, (ed.), op. cit. (3), pp. 77, 101.Google Scholar

54 Herbert, , op. cit. (26)Google Scholar, provides a full analysis with references to the documents. The significance of these records was first brought out in Herbert, , op. cit. (1), esp. pp. 117–18.Google Scholar

55 Sedgwick, A. to Darwin, C., 18 09 1831Google Scholar, in Burkhardt, and Smith, (eds.), op. cit. (4), i, p. 157.Google Scholar

56 Notebook no. 1.4, entry for 17 January 1832. See also DAR 32.1, fol. 20, where, in his first thoughts on Quail Island, he spoke of ‘the part of Volcanic rock which the former sea had not reached’, implying that the ocean rather than the land was shifting in level. Much stronger evidence that Darwin initially thought that the sea had changed level is provided by a slightly later passage in the notes on St Jago, where he writes: ‘Owing to this extreme regularity [of the ancient beach], I at one time felt inclined to think that the sea must have sunk, instead of the land raised.’ DAR 32.1, fol. 23v.

57 DAR 32.1, vol. 23v. See also Notebook 1.4, entry for 25 January 1832: ‘Reason for not think the sea has fallen.’

58 DAR 32.1, fol. 19, where Darwin also wrote ‘I could have scarcely credited that rocks nearly as hard as the conglomerates of older formation (viz of red-sandstone formation Anglesey) could daily be increasing under my own eyes.’ See also Notebook 1.4, entry for 17 January 1832. The criticism of Daubeny on lava was noted about St Jago; see DAR 32.1, fol. 35v. Lyell's emphasis on vera causae is well brought out in Laudan, , op. cit. (11), pp. 201–20.Google Scholar

59 Barlow, N. (ed.), Charles Darwin and the Voyage of the Beagle, London, 1945, pp. 155–7Google Scholar, and Keynes, (ed.), op. cit. (48), p. 25Google Scholar, both state that Darwin was using his blowpipe here as a way of testing the effects of burning lava on the shell bed. But this is highly improbable. As he wrote in an undated passage at the end of his field notebook, ‘shells action under blowpipe try the old ones’. The results of the test were recorded in his geological notes (DAR 32.1, fol. 21v): ‘These shells have lost their animal matter, that is they do not when heated alter or emit an animal smell.’

60 Darwin, C. to Fox, W. D., 05 1832Google Scholar, in Burkhardt, and Smith, (eds.), op. cit. (4), i, p. 232Google Scholar; for Lyell, see Rudwick, M. J. S., ‘Lyell on Etna, and the antiquity of the Earth’Google Scholar, in Schneer, (ed.), op. cit. (15), pp. 288304.Google Scholar

61 Secord, , op. cit. (37)Google Scholar, discusses the field styles of Sedgwick and Murchison.

62 Barlow, (ed.), op. cit. (3), p. 101Google Scholar. Henslow's view was typical, as shown in Bartholomew, M., ‘The singularity of Lyell’, History of Science, (1979), 17, pp. 276–93.CrossRefGoogle Scholar

63 Herbert, S., op. cit. (26).Google Scholar

64 Keynes, (ed.), op. cit. (48), p. 24Google Scholar. For the agenda before Darwin landed, see ibid., p. 13, entry for 13 December 1831, and Darwin, S. to Darwin, C., 12 02 1836Google Scholar, in Burkhardt, and Smith, (eds.), op. cit. (4), i, p. 488Google Scholar. For Darwin's self-identification as a geologist, see Gruber, and Gruber, , op. cit. (51)Google Scholar; Herbert, S., ‘The place of man in the development of Darwin's theory of transmutation: Part I. To July 1837’, Journal of the History of Biology, (1974), 7, pp. 217–58CrossRefGoogle Scholar; Herbert, , ‘Darwin the young geologist’Google Scholar and Rudwick, M. J. S., ‘Darwin and the world of geology’Google Scholar, both in Kohn, (ed.), op. cit. (14), pp. 483510 and pp. 511–18.Google Scholar

65 For the importance of such moments in the formation of disciplines, see Schaffer, S., ‘Scientific discoveries and the end of natural philosophy’, Social Studies of Science, (1986), 16, pp. 387420.CrossRefGoogle Scholar

66 Barlow, (ed.), op. cit. (3), p. 81.Google Scholar

67 Ibid. The ‘partial sinking’ is mentioned in Darwin's early notes (DAR 32.1, fols. 18, 29–30) and in one of the geological books that Darwin did in fact write; see Geological Observations on the Volcanic Islands Visited during the Voyage of H. M. S. Beagle, together with some Brief Notices of the Geology of Australia and the Cape of Good Hope, London, 1844, p. 9Google Scholar. In this later account, the change in level of the beds at Quail Island was no longer considered as an example of subsidence, although it had been in his early notes. When revisiting the island in 1836, Darwin was able to place St Jago in the larger framework of his global theory of subsidence and elevation that he had developed in South America; see ibid., p. 95.

68 Darwin, , op. cit. (67), pp. 93–6Google Scholar. The essay by J. W. Judd in Darwin, , op. cit. (1), pp. 157–65Google Scholar is the most helpful source for the place of Darwin's work in nineteenth-century studies of volcanoes. For background, see Dean, D., ‘Graham Island, Charles Lyell, and the craters of elevation controversy’, Isis, (1980), 71, pp. 571–88, esp. pp. 584–5Google Scholar; and Laudan, , op. cit. (11), p. 193Google Scholar. Contemporary expositions of the debate are in Daubeny, C., A Description of Active and Extinct Volcanoes; With Remarks on their Origin, their Chemical Phenomena, and the Character of their Products, as Determined by the Condition of the Earth during the Period of their Formation, London, 1826, esp. pp. 253–5Google Scholar, and Lyell, C., Principles of Geology, Being an Attempt to Explain the Former Changes of the Earth's Surface, by Reference to Causes now in Operation, London, 1830, i, pp. 386–98.Google Scholar

69 An analysis of the notebooks gives a very different picture of Darwin's changing self-image from that obtained in F. Sulloway, ‘Darwin's early intellectual development: an overview of the Beagle voyage (1831–1836)’, in Kohn, (ed.), op. cit. (14), pp. 121–54Google Scholar. Sulloway relies on the misleadingly guarded and cautious letters he wrote to Henslow.

70 Outram, D., ‘The language of natural power: the Eloges of Georges Cuvier and the public language of nineteenth-century science’, History of Science, (1978), 16, pp. 153–78, at p. 153CrossRefGoogle Scholar. I am indebted to Outram, , Georges Cuvier: Vocation, Science and Authority in Post-revolutionary France, Manchester, 1984, esp. chapter viiGoogle Scholar, ‘Geology, history and the shaping of a self-image’. For geology as a specialist vocation in Britain, see Porter, R., ‘Gentlemen and geology: the emergence of a scientific career, 1660–1920’, Historical Journal, (1978), 21, pp. 809–36.CrossRefGoogle Scholar

71 Keynes, (ed.), op. cit. (48), p. 19.Google Scholar

72 Ibid., p. 23.