1 The starting point for exploring the vast literature on Dalton's life is Smyth, A.L., John Dalton, 1766–1844: A Bibliography of Work by and about Him, 2nd edn, Manchester: Manchester Literary & Philosophical Publications Ltd, 1997 Google Scholar; and Greenaway, Frank, ‘Dalton, John (1766–1844), chemist and natural philosopher’, in Oxford Dictionary of National Biography (ODNB), Oxford: Oxford University Press, 2004 Google Scholar, online edn, October 2006, at www.oxforddnb.com, accessed 5 May 2016. Dalton, John, A New System of Chemical Philosophy, vol. 1, Part I, Manchester: S. Russell (for R. Bickerstaff, London), 1808, pp. 211–216 CrossRefGoogle Scholar, for his chemical atomic theory; Dalton, , A New System of Chemical Philosophy, vol. 1, Part II, Manchester: Russell & Allen (for R. Bickerstaff, London), 1810 Google Scholar.

2 On Higgins, William see Sullivan, William, ‘Memoir of Bryan and William Higgins, &c’., Dublin Quarterly Journal of Medical Science (1849) 8, pp. 465–495 Google Scholar; Wheeler, Thomas and Partington, James, The Life and Work of William Higgins, Chemist (1763–1825), Oxford: Pergamon Press, 1960 Google Scholar; Partington, James, ‘Bryan and William Higgins’, in Partington, A History of Chemistry, vol. 3, London: Macmillan, 1962, pp. 727–754 CrossRefGoogle Scholar, 736–754; Thackray, Arnold, ‘Higgins, William’, in Dictionary of Scientific Biography (DSB), vol. 6, New York: Charles Scribner's Sons, 1972, pp. 384–386 Google Scholar; David Knight, ‘Higgins, William (1763?–1825), chemist’, ODNB; and Mollan, Charles, ‘William Higgins (1763–1825)’, in Mollan, It's Part of What We Are: Some Irish Contributors to the Development of the Chemical and Physical Sciences (Science and Irish Culture no 3), vol. 1, Dublin: Royal Dublin Society, 2007, pp. 234–249 Google Scholar. The Dublin Society became the Royal Dublin Society in 1820; see Bright, Kevin, The Royal Dublin Society, 1815–1845, Dublin: Four Courts Press, 2004, p. 33 Google Scholar.

3 Higgins, William, A Comparative View of the Phlogistic and Antiphlogistic Theories. With Inductions. To which is Annexed, an Analysis of the Human Calculus, with Observations on its Origins, &c., London: J. Murray, 1789 Google Scholar. A second edition is reprinted in Wheeler and Partington, op. cit. (2). Higgins, William, Experiments and Observations on the Atomic Theory, and Electrical Phenomena, London: Longman, Hurst, Rees, Orme, and Brown, 1814 Google Scholar, reprinted in Wheeler and Partington, op. cit. (2).

4 Wheeler and Partington, op. cit. (2).

5 On Bryan Higgins's life and work see Sullivan, op. cit. (2); Partington, op. cit. (2), 727–736; Duncan, A.M., ‘William Keir's De Attractione Chemica (1778) and the concepts of chemical saturation, attraction and repulsion’, Annals of Science (1967) 23, pp. 149–173 CrossRefGoogle Scholar, 168–171; Gibbs, Frederick, ‘Bryan Higgins and his circle’, in Musson, Albert (ed.), Science, Technology and Economic Growth in the Eighteenth Century, London: Methuen & Co., 1972, pp. 195–207 Google Scholar; Arnold Thackray, ‘Higgins, Bryan’, DSB, vol. 6, pp. 382–384; David Knight, ‘Higgins, Bryan (c.1741–1818), medical practitioner and chemist’, ODNB; Charles Mollan, ‘Bryan Higgins (1737 or 1741–1818)’, in Mollan, It's Part of What We Are, op. cit. (2), pp. 187–196. For his works see Higgins, Bryan, A Philosophical Essay Concerning Light, London: J. Dodsley, 1776 Google Scholar; Higgins, , Experiments and Observations Relating to Acetous Acid, Fixable Air, Dense Inflammable Air, &c., London: T. Cadell, 1786 Google Scholar; and Higgins, , Minutes of the Society for Philosophical Experiments and Conversations, London: T. Cadell and W. Davies, 1795 Google Scholar.

6 Partington, op. cit. (2).

7 Thackray, Arnold, ‘The origin of Dalton's chemical atomic theory: Daltonian doubts resolved’, Isis (1966) 57, pp. 35–55 CrossRefGoogle Scholar, 37.

8 Higgins, Experiments and Observations, op. cit. (3), p. 29.

9 Davy, Humphry, Six Discourses Delivered before the Royal Society at their Anniversary Meetings, on the Award of the Royal and Copley Medals, London: John Murray, 1827, pp. 125–131 Google Scholar, 127.

10 Partington, James, ‘The origins of the atomic theory’, Annals of Science (1939) 4, 245–282 CrossRefGoogle Scholar, 281. Kelham also asserted that Dalton developed his ideas independently of Bryan Higgins. See Kelham, B.B., ‘Atomic speculation in the late eighteenth century’, in Cardwell, D.S.L. (ed.), John Dalton & the Progress of Science, Manchester: Manchester University Press, 1968, pp. 109–124 Google Scholar, 113, 122–123.

11 Grossman, Mark, ‘John Dalton and the London atomists: William and Bryan Higgins, William Austin, and new Daltonian doubts about the origin of the atomic theory’, Notes and Records: The Royal Society Journal of the History of Science (2014) 68, pp. 339–356 CrossRefGoogle Scholar, 346–352. See Cantor, Geoffrey, Quakers, Jews, and Science: Religious Responses to Modernity and the Sciences in Britain, 1650–1900, Oxford: Oxford University Press, 2005 CrossRefGoogle Scholar, for context regarding the relationship between Dalton and Allen and the Quaker approach to science.

12 Dalton, Part II, op. cit. (1).

13 Bryan accused Priestley of plagiarizing his experiments. For an account of the dispute see Schofield, Robert, The Enlightened Joseph Priestley: A Study of His Life and Work from 1773 to 1804, University Park: Pennsylvania State University Press, 2004, pp. 124–129 Google Scholar.

14 Jungnickel, Christa and McCormmach, Russell, Cavendish, Philadelphia: The American Philosophical Society, 1996, pp. 328–329 Google Scholar.

15 Higgins, Minutes of the Society for Philosophical Experiments and Conversations, op. cit. (5). Partington, op. cit. (2), p. 736. For a detailed discussion of Bryan's society see Averley, Gwen, ‘The “social chemists”: English chemical societies in the eighteenth and early nineteenth century’, Ambix (1986) 33, pp. 99–128 CrossRefGoogle Scholar, 102–107.

16 Bryan Higgins to W.H.C. Cavendish-Bentinck, 3rd Duke of Portland, 7 August 1795, Portland Welbeck archive, Manuscripts and Special Collections, The University of Nottingham, Pw F 5119, referenced with permission. Claire Nutt, ‘Crawford, Adair (1748–1795), physician and chemist’, ODNB.

17 Lewis's influence was suggested by Gibbs, op. cit. (5), p. 205. Details of Bryan's journey to Jamaica are described in Journals of the Assembly of Jamaica (JAJ) [25 October 1791–4 August 1797] (1808) 9, pp. 551, 584, 621–622; [31 October 1797–23 June 1802] (1807) 10, pp. 41, 90, 98, 261, 469, 555, 576–577.

18 Bryan Higgins, Fragment of the Fourth Part of Dr. Higgins's Observations and Advices, for the Improvement of the Manufacture of Sugar and Rum. To Which is Added, the Description of a Kiln for the Drying of Coffee, Projected by Dr. Higgins, Jamaica: Printed by Alexander Aikman, 1803.

19 Coutts, A., ‘William Cruickshank of Woolwich, Annals of Science (1959) 15, pp. 121–133 CrossRefGoogle Scholar, 128, 130; David Cumming, ‘MacCulloch, John (1773–1835), surgeon and geologist’, ODNB.

20 Bryan used the same modus operandi with the Royal Institution, offering initial services at no cost, to secure his consulting position in Jamaica. JAJ, op. cit. (17) (1808) 9, p. 584. The Royal Institution was actively seeking to fill lectureships, and Bryan may have been seeking an appointment, based on his earlier attempt to replace Adair Crawford at the Royal Military Academy, Woolwich. Higgins's report on the laboratory was filed with the rough minutes suggesting that he found nothing of significance or that he was a victim of politics, with Davy protecting his turf, using his influence with the managers to minimize the importance of any of Higgins's findings about the laboratory. No rough or draft minutes prior to 1848 are held by the Royal Institution. Personal communication from Jane Harrison, Royal Institution, 17 September 2013. For a discussion of Davy's activities amid the politics surrounding the Royal Institution laboratory and the Board of Agriculture during the period see James, Frank, ‘“Agricultural chymistry is at present in it's infancy”: the Board of Agriculture, the Royal Institution and Humphry Davy’, Ambix (2015) 62, pp. 363–385 CrossRefGoogle ScholarPubMed. For details of Bryan's interactions with the Royal Institution see Greenaway, Frank (ed.), The Archives of the Royal Institution of Great Britain in Facsimile: Minutes of Managers’ Meetings, 1799–1900, vols. 1–2, Ilkley: Scholar Press, 1971 Google Scholar, 5 December 1803, pp. 171–175, 23 January 1804, pp. 202–203. Also see Unwin, Patrick and Unwin, Robert, ‘Humphry Davy and the Royal Institution of Great Britain’, Notes & Records of the Royal Society (2009) 63, pp. 7–33 CrossRefGoogle ScholarPubMed, 17. Contrary to Unwin and Unwin, the evidence suggests that Higgins approached Davy offering to review the laboratory.

21 According to Sullivan, op. cit. (2), p. 484, Bryan apparently acquired his estate through his marriage to Jane Welland.

22 Articles of the Peace, ‘Articles by Thomas Pearson of Walford, farmer and maltster, against Bryan Higgins of Walford, esquire, who had threatened him with a sword and had earlier threatened to shoot him’, 18 July 1816, DocRefNo Q/SB 1816 T/270, Staffordshire Record Office, Stafford.

23 ‘Lease of a messuage and lands in Bowers, Standon’, 25 May 1786, DocRefNo M762B/16, William Salt Library, Stafford.

24 Traverses, ‘Case against Bryan Higgins of Eccleshall, esquire, charged with assaulting George Bedson, Apr 1816’, DocRefNo Q/SB 1816 E/192, Staffordshire Record Office, Stafford.

25 Orders, ‘Draft order relating to the case of Bryan Higgins of Walford, found guilty of assault, Jul 1816’, DocRefNo Q/SB 1816 T/203, Staffordshire Record Office, Stafford.

26 ‘Articles by Thomas Pearson of Walford’, op. cit. (22).

27 ‘Draft order’, op. cit. (25).

28 Higgins, William, ‘On Dr. Murray's statement respecting the origin of the doctrine of definite proportions, and the arrangement of the elementary principles of chemical compounds’, Philosophical Magazine (1819) 53, pp. 401–410 CrossRefGoogle Scholar, 410.

29 Dalton, Part II, op. cit. (1), p. 444.

30 Higgins, Experiments and Observations Relating to Acetous Acid, op. cit. (5), pp. 285–300.

31 Austin, William, ‘Experiments on the analysis of the heavy inflammable air’, Philosophical Transactions of the Royal Society of London (1790) 80, pp. 51–72 Google Scholar, 56. Austin, at 68, also cited page 293 of Acetous Acid, which mentions Bryan's experiments on the heating of charcoal to form heavy inflammable air.

32 Grossman, op. cit. (11), pp. 344–345. Dalton's laboratory notebook entries show that he may have already been aware of Bryan's work on heavy inflammable air in October 1803, when Dalton began experiments on gaseous compounds of carbon, including the heating of wet charcoal and the incomplete combustion of ether. Roscoe, Henry and Harden, Arthur, A New View of the Origin of Dalton's Atomic Theory, London: Macmillan, 1896, pp. 59–60 Google Scholar. Bryan referenced experiments on the combustion of ‘the heavier inflammable air carrying ethereal vapour’ in Acetous Acid. Higgins, Experiments and Observations Relating to Acetous Acid, op. cit. (5), pp. 292. See also Dalton, Part II, op. cit. (1), p. 446.

33 Higgins, Experiments and Observations Relating to Acetous Acid, op. cit. (5), pp. 301–310 ff.

34 For additional information on the development and reception of Dalton's atomic theory see Rocke, Alan, Chemical Atomism in the Nineteenth Century: From Dalton to Cannizzaro, Columbus: Ohio State University Press, 1984 Google Scholar. See also Chang, Hasok, Is Water H₂O? Evidence, Realism and Pluralism, Cambridge: Springer, 2014, pp. 133–201 Google Scholar. For the history of caloric see Fox, Robert, The Caloric Theory of Gases from Lavoisier to Regnault, Oxford: Clarendon Press, 1971 Google Scholar; Fox, ‘Dalton's caloric theory’, in Cardwell, op. cit. (10), pp. 187–202.

35 Fox, The Caloric Theory of Gases, op. cit. (34), pp. 11, 112. Partington, op. cit. (10), pp. 278, 281; Partington, op. cit. (2), p. 767.

36 Rocke, Alan, ‘What did “theory” mean to nineteenth-century chemists?’, Foundations of Chemistry (2013) 15, pp. 145–156 CrossRefGoogle Scholar, 150, original emphasis.

37 Wheeler and Partington, op. cit. (2), p. 128.

38 Roscoe and Harden, op. cit. (32), pp. 71–72.

39 Dalton, vol. 1, Part I, op. cit. (1), p. 188.

40 Bryan Higgins, Experiments and Observations Relating to Acetous Acid, op. cit. (5), p. 315.

41 Partington, op. cit. (2), p. 735.

42 Higgins, Minutes of the Society for Philosophical Experiments and Conversations, op. cit. (5), p. 63.

43 Roscoe and Harden, op. cit. (32), pp. 25, 41.

44 Roscoe and Harden, op. cit. (32), p. 16.

45 Dalton, vol. 1, Part I, op. cit. (1), p. 189.

46 Dalton, John, ‘On the constitution of mixed gases’, Manchester Memoirs (1802) 5, pp. 535–550 Google Scholar, 537; Dalton, , ‘On the expansion of elastic fluid by heat’, Manchester Memoirs (1802) 5, pp. 595–602 Google Scholar, 601.

47 Dalton, John, ‘Letter from Mr. Dalton, containing observations concerning the determination of the zero of heat, the thermometrical gradation, and the law by which dense or non-elastic fluids expand by heat’, A Journal of Natural Philosophy, Chemistry, and the Arts (1803) 5, pp. 34–36 Google Scholar, 35.

48 Roscoe and Harden, op. cit. (32), pp. 130–141.

49 Roscoe and Harden, op. cit. (32), p. 131.

50 Hope's letter referencing Dalton's 8 November response is undated, but Hope's next letter to Dalton is dated 29 March 1804. Roscoe and Harden, op. cit. (32), p. 138. Roscoe and Harden arranged the letters chronologically for all of the correspondents, so Hope's undated letter was apparently written before 29 March 1804. Furthermore, in the undated letter, Hope describes experiments he conducted addressing the density of water as a function of temperature, stating, ‘I know not whether they will seem as decisive to you as they do to me’. Roscoe and Harden, op. cit. (32), p. 136. Dalton's laboratory notebook contains an entry referring to ‘a repetition of Hope's experiment’ on 16 December 1803. Roscoe and Harden, op. cit. (32), p. 61. Based on the chronological order of the letters and Dalton's reference to Hope's experiments, the undated letter likely dates from mid-November to early December 1803. Hope read his paper on the density of water on 9 January 1804, and stated, ‘It was in consequence of a communication with which Mr. Dalton favoured me, three months ago, that my attention was directed to this subject’, indicating that his meeting with Dalton in Manchester probably occurred sometime in early October 1803. Hope, Thomas, ‘Experiments and observations upon the contraction of water by heat at low temperatures’, Transactions of the Royal Society of Edinburgh (1805) 5, pp. 379–405 CrossRefGoogle Scholar, 384.

51 Roscoe and Harden, op. cit. (32), pp. 134. Dalton's 8 November response may reflect the caloric model he had in mind in August 1803, which, according to his laboratory notes, was the month during which he conducted his latest experiments on gaseous diffusion. Roscoe and Harden, op. cit. (32), p. 59.

52 Many eighteenth- and early nineteenth-century chemists had various loose notions of caloric surrounding particles. For example, Thomson mentioned the term ‘atmosphere of caloric’ once in System of Chemistry. Thomas Thomson, A System of Chemistry, vol. 3, Edinburgh: Bell & Bradfute, and E. Balfour, 1802, p. 236. But Thomson and others did not allude to the diameter of the caloric atmosphere as a measure of atomic size, nor did they use language that closely matched Dalton's wording in his laboratory notebook, as is the case for Bryan. In fact, Thomson's use of the phrase occurs in the context of a discussion relating to Boscovich's atomic model, in which atoms are dimensionless point forces, with no diameter at all. See Mauskopf, Seymour, ‘Thomson before Dalton: Thomas Thomson's considerations of the issue of combining weight proportions prior to the acceptance of Dalton's chemical atomic theory’, Annals of Science (1969) 25, pp. 229–242 CrossRefGoogle Scholar, 236.

53 Roscoe and Harden, op. cit. (32), p. 27.

54 Higgins, Experiments and Observations Relating to Acetous Acid, op. cit. (5), p. 317. Bryan's observations on specific gravities are referenced by Duncan, Alistair, Laws and Order in Eighteenth-Century Chemistry, Oxford: Clarendon Press, 1996, p. 89 Google Scholar.

55 Partington, op. cit. (2), p. 735.

56 Higgins, A Philosophical Essay Concerning Light, op. cit. (5). Partington, op. cit. (2), pp. 732–734.

57 Dalton, John, ‘Observations on Dr. Bostock's review of the atomic principles of chemistry’, A Journal of Natural Philosophy, Chemistry, and the Arts (1811) 29, pp. 143–151 Google Scholar, 145–146. Bostock, John, ‘Remarks on Mr. Dalton's hypothesis of the manner in which bodies combine with each other’, A Journal of Natural Philosophy, Chemistry, and the Arts (1811) 28, pp. 280–292 Google Scholar.

58 Dalton, op. cit. (57), p. 147. See Grossman, op. cit. (11), p. 350.

59 Higgins, Minutes of the Society for Philosophical Experiments and Conversations, op. cit. (5), pp. 21–22. Grossman, op. cit. (11).

60 Mauskopf, op. cit. (52); on the potential influence of René Haüy see Mauskopf, , ‘Haüy's model of chemical equivalence: Daltonian doubts exhumed’, Ambix (1970) 17, pp. 182–191 CrossRefGoogle Scholar, 191.

61 In 1812, an anonymous author using the initials ‘LOC’ noted that Dalton's caloric model described in Thomson's System of Chemistry was similar to Bryan Higgins's caloric model described in Acetous Acid and attributed priority for the caloric model to him. LOC, ‘An attempt to explain the phenomena of caloric’, A Journal of Natural Philosophy, Chemistry, and the Arts (1812) 31, 95–107 Google Scholar, 106. Although LOC's correspondence was overlooked by the scientific community at large, Dalton almost certainly read the correspondence and knew of LOC's comments about Bryan's priority for the caloric model. Dalton had the 1812 volume of Nicholson's Journal in his personal library at the time of his death, he submitted numerous papers to the periodical throughout his career, and his publications reflect his intense interest in the subject of heat, so it is difficult to support the position that he had overlooked LOC's paper. Olivier, Ronald and Carrier, Michael, The Library of John Dalton, [Salford]: University of Salford, 2006, p. 25 Google Scholar.