The author thanks the National Science Foundation for support to research and write this paper. The author also wishes to thank Professor Robert E. Schofield of Case Western Reserve University for his helpful comments, and Ms Paula Baudoux, Inter-library Loan Librarian of the Atlanta Public Library, for her help in locating and borrowing volumes needed for this study.

¹ Born Benjamin Thompson, he became a Count of the Holy Roman Empire in 1792. I have used Rumford throughout this article to avoid confusion.

² According to Sanborn G. Brown, Rumford's cannon-boring experiment can be ‘found in almost every textbook on general physics’. See Brown, Sanborn C., ‘Count Rumford and the caloric theory of heat’, Proceedings of the American Philosophical Society, xcii (1949), 316.Google Scholar

³ Lilley, S., ‘Attitudes to the nature of heat about the beginning of the nineteenth century’, Archives internationales d'histoire des sciences, xxvii (1947–1948), 630–9.Google Scholar

⁴ Henry, William, ‘A review of some experiments which have been supposed to disprove the materiality of heat’, Philosophical magazine, xv (1803), 15.Google Scholar

⁵ Schofield, Robert E., Mechanism and materialism. British natural philosophy in the age of reason (Princeton, N.J., 1970), pp. 185–90.Google Scholar

⁶ Ibid., pp. 278–87. For a discussion of Leslie's investigations of heat, see Olson, Richard G., ‘Count Rurnford, Sir John Leslie, and the study of the nature and propagation of heat at the beginning of the nineteenth century’, Annals of science, xxvi (1970), 273–304.CrossRefGoogle Scholar

⁷ A selection of Rumford obituaries can be found in Ellis, George E., Memoir of Benjamin Thompson, Count Rumford with notices of his daughter (reprint of 1871 edition, Boston, 1972), pp. 614–32.Google Scholar

⁸ Quoted in ibid., p. 630. Thomson's pique may have resulted from some remarks made by Rumford in a paper of 1803 in which he criticized Thomson's criticism of an earlier paper; see Rumford, Count [Thompson, Benjamin], The complete works of Count Rumford (4 vols., Boston, [1870–1875]), ii. 256–7.Google Scholar

⁹ Joule, James Prescott ‘On the mechanical equivalent of heat’, Philosophical transactions of the Royal Society of London, cxl (1850), 62.Google Scholar

¹⁰ Tyndall, John, Heat a mode of motion (4th edn., New York, 1873), p. 54.Google Scholar

¹¹ Brown, Sanborn C., Count Rumford, physicist extraordinary (Garden City, N.Y., 1962).Google Scholar

¹² Sparrow, W. J., Count Rumford of Woburn, Mass. (New York, 1965).Google Scholar

¹³ See, for example, Sharlin, Harold I., The convergent century (London, New York, and Toronto, 1966), pp. 18–19Google Scholar, and Mason, Stephen F., A history of the sciences (revised edn., New York, 1962), pp. 486–7.Google Scholar

¹⁴ Davy, Humphry, The collected works of Sir Humphry Davy, ed. by Davy, John (9 vols., London, 1839), ii. 391.Google Scholar Four secondary works do mention the ether in Rumford's natural philosophy, but only in passing: see Brown, Sanborn C., ‘Count Rumford's concept of heat’, American journal of physics, xx (1952), 331CrossRefGoogle Scholar; Olson, , op. cit. (6), 279, 282Google Scholar; Brush, Stephen G., ‘The development of the kinetic theory of gases, VII. Heat conduction and the Stefan-Boltzmann law’, Archive for history of exact sciences, xi (1973), 43–4Google Scholar; and Cardwell, D. S. L., From Watt to Claustus. The rise of thermodynamics in the early industrial age (London, 1971), p. 103.Google Scholar

¹⁵ Rumford, , op. cit. (8), ii. 172.Google Scholar

¹⁶ Ibid., ii. 172–3.

¹⁷ Ibid. I use ‘mechanism’ and ‘materialism’ in the sense in which they are used in Schofield, op. cit (5), passim.

¹⁸ Rumford, , op. cit. (8), ii. 172.Google Scholar

¹⁹ Ibid., ii. 105.

²⁰ Ibid., ii. 106.

²¹ Ibid., ii. 107–8.

²² Ibid., ii. 108.

²³ Ibid., ii. 104.

²⁴ Ibid.

²⁵ Ibid.

²⁶ Ibid., ii. 322–3; also see ibid., i. 307 n.

²⁷ Ibid., ii. 124.

²⁸ Ibid., ii. 125.

²⁹ In a paper in 1807 Rumford complained that he was ‘not sufficiently well versed in the higher geometry to understand fully the calculations of M. La Place’; see ibid., ii. 309.

³⁰ For the application of analysis to the problem of an elastic ether in the 1830s, see Whittaker, Edmund, A history of the theories of aether and electricity, Vol. 1, The classical theories (New York, 1973), pp. 128–69.Google Scholar

³¹ For a textbook treatment of British natural philosophy of the 1790s, see Nicholson, William, An introduction to natural philosophy (3rd edn., 2 vols., London, 1790).Google Scholar

³² Schofield, , op. cit. (5), pp. 13–15, 108–14.Google Scholar

³³ For an interesting discussion of Young and the ether, see Cantor, Geoffrey, ‘The changing role of Young's ether’, The British journal for the history of science, v (1970–1971), 44–62.CrossRefGoogle Scholar

³⁴ Sparrow, , op. cit. (12), p. 18.Google Scholar

³⁵ Brown, , op. cit. (11), pp. 1–8.Google Scholar

³⁶ Rumford, , op. cit. (8), ii. 188.Google Scholar As I was unable to find a trace of a work by Boerhaave entitled ‘Treatise on fire’, I am assuming that Rumford is referring to the extensive section ‘Of fire’ in Boerhaave's A new method of chemistry.

³⁷ Rumford, , op. cit. (8), i. 36.Google Scholar For my discussion of Rumford and Boerhaave, I have used the edition quoted by Rumford in his 1781 paper: Boerhaave, Herman, A new method of chemistry, trans, by Shaw, Peter (2nd edn., 2 vols., London, 1741).Google Scholar

³⁸ Brown, , op. cit. (11), pp. 90–1.Google Scholar

³⁹ Schofield, , op. cit. (5), pp. 152–4, 186–9.Google Scholar

⁴⁰ Ibid., p. 152.

⁴¹ Boerhaave, , op. cit. (37), i. 206.Google Scholar

⁴² Ibid., i. 208, 247.

⁴³ Ibid., i. 222.

⁴⁴ Ibid., i. 223.

⁴⁵ Ibid., i. 220, footnote e.

⁴⁶ Rumford, , op. cit. (8), ii. 104.Google Scholar

⁴⁷ Ibid., ii. 193.

⁴⁸ In his An experimental inquiry into the nature and propagation of heat (London and Edinburgh, 1804).

⁴⁹ ‘Of the propagation of heat in fluids’, Part I, in Rumford, , op. cit. (8), i. 239–335.Google Scholar

⁵⁰ For example, ‘An inquiry concerning the weight ascribed to heat’, ibid., ii. 1–22.

⁵¹ Ibid., i. 307n. Rumford repeated these sentiments in the second half of this paper, published in the following year (1798); see ibid., i. 346 ff. Rumford went even further and associated his motions of liquids (convection currents) with ‘the vital principle in living animals’; see ibid., i. 363.

⁵² Herschel's papers on this subject can be found in the Philosophical transactions, (1800). pp. 255–83, 284–92, 293–326, 437–538Google Scholar; for an article discussing Herschel's own problems with his experimental data, see Lovell, D. J., ‘Herschel's dilemma in the interpretation of thermal radiation’, Isis, lix (1968), 46–60.CrossRefGoogle Scholar

⁵³ ‘Outlines of experiments and inquiries respecting sound and light’, Philosophical transactions, (1800), pp. 106–50.Google Scholar

⁵⁴ Englefield, H. C., ‘Experiments on the separation of light and heat by refraction’, Journal of the Royal Institution, i (1802), 203–8.Google Scholar

⁵⁵ Rumford, , op. cit. (8), ii. 54Google Scholar, and iv. 75.

⁵⁶ Ibid., iv. 210.

⁵⁷ Another possible explanation of Rumford's willingness to accept a mechanical theory of heat is his contact with Franz von Baader, whom Rumford met while in the service of the Elector of Bavaria in the 1780s. Our knowledge of von Baader will be increased upon the completion of the research being done by Professor Reese V. Jenkins of Case Western Reserve University.

⁵⁸ Brush, Stephen G., ‘The wave theory of heat: a forgotten stage in the transition from the caloric theory to thermodynamics’, The British journal for the history of science, v (1970–1971), 145–67.CrossRefGoogle Scholar

⁵⁹ Ibid., p. 146.

⁶⁰ One difference between Rumford's concept of the ether and that of the Encyclopaedia Britannica (see footnote 59) is that Rumford did not explain natural phenomena in terms of forces between the particles of the ether and the particles of matter. In fact, I have found only one place where Rumford explicitly mentions the particles of the ether, and this in a paper dating from 1812, one of his last; see Rumford, , op. cit. (8), ii. 408.Google Scholar