Marking out a disciplinary common ground: The role of chemical pedagogy in establishing the doctrine of affinity at the heart of British chemistry

Summary

This paper presents a case study that contributes to the current debate among historians of chemistry concerning the role and influence of pedagogy in science. Recently, Bernadette Bensaude-Vincent and her colleagues concluded that in nineteenth-century France, ‘textbooks played an important role in discipline building and in creating theories’.1 Developing this idea further, this paper examines the dissemination of knowledge through face-to-face chemical lectures, showing that the influence of pedagogical strategy on theoretical content of the science is far from negligible. The pedagogy of William Cullen was essentially responsible for the prevalence of the doctrine of affinity in British chemistry from the 1760s onwards. Cullen used his affinity theory as a pedagogical tool that to a large extent defined his discipline, and the pedagogical pyramid that he headed similarly ensured that the doctrine would remain at the heart of British chemistry. From a pedagogical tool, the doctrine of affinity was transformed over time into a chemical tool, offering British chemists a disciplinary common ground that both set and reinforced the boundaries to their discipline.

¹A. Garcia-Belmar, B. Bensaude-Vincent and J.R. Bertomeu-Sánchez, ‘The Power of Didactic Writings: French Chemistry Textbooks of the Nineteenth Century’, in Pedagogy and the Practice of Science: Historical and Contemporary Perspectives, edited by D. Kaiser (Cambridge, MA, 2005), 243.

Notes

¹A. Garcia-Belmar, B. Bensaude-Vincent and J.R. Bertomeu-Sánchez, ‘The Power of Didactic Writings: French Chemistry Textbooks of the Nineteenth Century’, in Pedagogy and the Practice of Science: Historical and Contemporary Perspectives, edited by D. Kaiser (Cambridge, MA, 2005), 243.

²O. Hannaway, The Chemists and the Word: The Didactic Origins of Chemistry (Baltimore, MD, 1975), A. Garcia-Belmar, B. Bensaude-Vincent, and J.R. Bertomeu-Sánchez, ‘The Power of Didactic Writings: French Chemistry Textbooks of the Nineteenth Century’, in Pedagogy and the Practice of Science: Historical and Contemporary Perspectives, edited by D. Kaiser (Cambridge, MA, 2005). The most recent contribution to the debate is J. Frercks and M. Markert, ‘The Invention of Theoretische Chemie: Forms and Uses of German Chemistry Textbooks, 1775–1820’, Ambix, 54 (2007), 146–71 which explores the origins of the German concept of theoretische chemie in textbooks.

³L. Rosner, ‘Ants in the Academy: Formic Acid and the University Dissemination of Enlightenment Science’, Eighteenth-Century Thought, 2 (2004), 207–31. Rosner's book-length study of the teaching of medicine in Edinburgh is also an important contribution to the field of pedagogy studies. L. Rosner, Medical Education in the Age of Improvement: Edinburgh Students and Apprentices 1760–1826. (Edinburgh, 1991).

⁴D. Kaiser, Drawing Theories Apart: The Dispersion of Feynman Diagrams in Postwar Physics (Chicago, 2005) and D. Kaiser, ‘Making Tools Travel: Pedagogy and the Transfer of Skills in Postwar Theoretical Physics’, in Pedagogy and the Practice of Science: Historical and Contemporary Perspectives, edited by D. Kaiser (Cambridge, MA, 2005), 41–74.

⁵On Cullen's influential chemistry teaching, see A.L. Donovan, Philosophical Chemistry in the Scottish Enlightenment: The Doctrines and Discoveries of William Cullen and Joseph Black (Edinburgh, 1975), J. Golinski, Science as Public Culture: Chemistry and Enlightenment in Britain, 1760–1820 (Cambridge, 1992), J.R.R. Christie, A. Doig, J.P.S. Ferguson, I.A. Milne, and R. Passmore, ‘William Cullen and the Practice of Chemistry’, in William Cullen and the Eighteenth Century Medical World (Edinburgh, 1993), 98–109, J.R.R. Christie, ‘Historiography of Chemistry: Hermann Boerhaave and William Cullen’, Ambix, 41 (1994), 4–19,

⁶D. Knight, Sources for the History of Science 1660–1914 (London, 1975), 32.

⁹A.M. Duncan, Laws and Order in Eighteenth-Century Chemistry (Oxford, 1996), 224.

⁷J. Eklund, ‘Chemical Analysis and the Phlogiston Theory 1738–1772: Prelude to Revolution’ (Ph.D. thesis, Yale University, 1971).

⁸William Nicholson, A Dictionary of Chemistry. (London, 1795), vol. I, 153–87.

¹⁰R. Kirwan, ‘Experiments and Observations on the Specific Gravities and Attractive Powers of Various Saline Substances’, Philosophical Transactions of the Royal Society of London, 71 (1781), 7–41, R. Kirwan, ‘Continuation of the Experiments and Observations on the Specific Gravities and Attractive Powers of Various Saline Substances’, Philosophical Transactions of the Royal Society of London, 72 (1782), 179–xxxv and R. Kirwan, ‘Conclusion of the Experiments and Observations Concerning the Attractive Powers of the Mineral Acids’, Philosophical Transactions of the Royal Society of London, 73 (1783), 15–84.

¹¹S. Johnson and J. Lynch, Samuel Johnson's Dictionary: Selections from the 1755 Work (London, 2002), 142.

¹²Rosner offers a useful analysis of the slippery distinction between the pedagogical and research contexts (or the Academy and the University) in L. Rosner, ‘Ants in the Academy: Formic Acid and the University Dissemination of Enlightenment Science’, Eighteenth-Century Thought, 2 (2004), 207–31, 211–13

¹³E.F. Geoffroy, ‘Tables Des Differents Rapports Observes En Chimie Entre Differentes Substances’, Histoire (et Memoires) de L'Academie Royale des Sciences, 1718 (1719), 202–12, 203.

¹⁴E.F. Geoffroy, ‘Tables Des Differents Rapports Observes En Chimie Entre Differentes Substances’, Histoire (et Memoires) de L'Academie Royale des Sciences, 1718 (1719), 202–12, 203.

¹⁵In 1731, Peter Shaw referred to Geoffroy's Memoire in a summary of a proposed course in philosophical chemistry. P. Shaw and F. Hauksbee, An Essay for Introducing a Portable Laboratory: By Means Whereof All the Chemical Operations Are Commodiously Perform'd for the Purposes of Philosophy, Medicine, Metallurgy, and a Family (London, 1731).

¹⁶For a more detailed enumeration of the very few early British references to Geoffroy, see G. Taylor, ‘Variations on a Theme: Patterns of Congruence and Divergence among 18th Century Chemical Affinity Theories’ (Ph.D. thesis, University of London, 2006), 55–67.

¹⁷P. Galison, Image and Logic: A Material Culture of Microphysics (1997), P. Galison and A. Assmus, ‘Artificial Clouds, Real Particles’, in The Uses of Experiment: Studies in the Natural Sciences, edited by D. Gooding, T.J. Pinch and S. Schaffer (Cambridge, 1989), 225–74.

¹⁸L. Rosner, ‘Ants in the Academy: Formic Acid and the University Dissemination of Enlightenment Science’, Eighteenth-Century Thought, 2 (2004), 207–31, 214.

¹⁹See also R.E. Schofield, Mechanism and Materialism: British Natural Philosophy in an Age of Reason, Mechanism and Materialism (Princeton, NJ, 1970), 216.

²⁰M. Polanyi, Personal Knowledge: Towards a Post-Critical Philosophy (London, 1962), 60.

²¹This process has been clearly described in Kaiser's works. D. Kaiser, Drawing Theories Apart: The Dispersion of Feynman Diagrams in Postwar Physics (Chicago, 2005), D. Kaiser, ‘Making Tools Travel: Pedagogy and the Transfer of Skills in Postwar Theoretical Physics’, in Pedagogy and the Practice of Science: Historical and Contemporary Perspectives, edited by D. Kaiser (Cambridge, MA, 2005), 41–74.

²²T. Thomson, The History of Chemistry (London, 1830), 157.

²³G. Taylor, ‘Variations on a Theme: Patterns of Congruence and Divergence among 18th Century Chemical Affinity Theories’ (Ph.D. Thesis, University of London, 2006), and G. Taylor, ‘Common Grounds: Variation and Consensus in 18th Century British Theories of Chemical Affinity’ (forthcoming).

²⁴M. Polanyi, Personal Knowledge: Towards a Post-Critical Philosophy (London, 1962), 56.

²⁵P. Galison, Image and Logic: A Material Culture of Microphysics (1997).

²⁶O. Hannaway, The Chemists and the Word: The Didactic Origins of Chemistry (Baltimore, MD, 1975).

²⁷A. Garcia-Belmar, B. Bensaude-Vincent, J.R. Ramón Bertomeu-Sánchez, ‘The Power of Didactic Writings: French Chemistry Textbooks of the Nineteenth Century’, in Pedagogy and the Practice of Science: Historical and Contemporary Perspectives, edited by D. Kaiser (Cambridge, MA, 2005), 243.

²⁸On pedagogical continuity, see P. Galison, Image and Logic: A Material Culture of Microphysics (1997), 21 ff.

³⁰W. Cullen, Fragment of a Lecture by Cullen on Saltpetre, Aquafortis and Elective Attractions, Separating and Combining, 1749, MS 1060, Cullen Papers, Glasgow University Library, Glasgow, f. 17.

²⁹Cullen's chemistry lectures were open to all those who had an interest in the subject, and this apparently included many from outside the university, whose interests were often commercial. J. Golinski, ‘Utility and Audience in Eighteenth Century Chemistry: Case Studies of William Cullen and Joseph Priestley’, British Journal for the History of Science, 21 (1988), 1–31, 5.

³¹E.g. W. Cullen, Notes Taken by Charles Blagden from Lectures on Chemistry 1765–6, MS 1922, Blagden Papers, Wellcome Library for the History and Understanding of Medicine, London, lectures 17 and 18.

³³T. Thomson, The History of Chemistry (London, 1830), 307.

³²T. Thomson, The History of Chemistry (London, 1830), 304.

³⁴J. Golinski, Science as Public Culture: Chemistry and Enlightenment in Britain, 1760–1820 (Cambridge, 1992), 17.

³⁵Glasgow University library holds a vast number of manuscripts, comprising Cullen's own notes, as well as fragments of the lecture notes of students. The number of MS held at Glasgow University Library is too great to list each MS individually. Quotations from individual MS will be specified hereafter. Edinburgh University library and the Royal College of Physicians in Edinburgh are two further repositories for the enormous number of Cullen papers still extant. The fact that Cullen lectured in English rather than Latin confers the added benefit that most of the notes of his chemistry lectures are in that language. Neville wrote: ‘I find that Dr. Cullen notwithstanding his present eminence had but a poor education and had not acquired much learning before he was 40 years old. … Knowles heard that one J. Brown, a great Latinist, who writes many Theses for those who are not ashamed to bring out the composition of another as their own, assists Cullen in his Latin’. S. Neville and B. Cozens-Hardy, The Diary of Sylas Neville 1767–1788 (London, 1950), 144. Although Cullen lectured in English, examinations were still held in Latin, and Neville also testifies to the fact that in spite of Cullen's alleged lack of facility with the language he was nevertheless sufficiently proficient to hear examinations without assistance.

³⁶J. Golinski, Science as Public Culture: Chemistry and Enlightenment in Britain, 1760–1820 (Cambridge, 1992), 42–3 and A.L. Donovan, Philosophical Chemistry in the Scottish Enlightenment: The Doctrines and Discoveries of William Cullen and Joseph Black (Edinburgh, 1975), 271.

³⁷S. Neville and B. Cozens-Hardy, The Diary of Sylas Neville 1767–1788 (London, 1950), 151.

³⁸J. Elliot, Philosophical Observations on the Senses of Vision and Hearing’ to Which Are Added, a Treatise on Harmonic Sounds, and an Essay on Combustion and Animal Heat (London, 1780), 122–3.

³⁹M. Crosland, ‘The Use of Diagrams as Chemical ‘Equations’ in the Lecture Notes of William Cullen and Joseph Black’, Annals of Science, 15 (1959), 75–90.

⁴⁰J. Crellin, ‘The Development of Chemistry in Britain through Medicine’ (Ph.D. thesis, University of London, 1969). It is probably important to note here that there are also a huge number of manuscripts extent pertaining to Cullen's other medical courses, including lecture notes on materia medica, clinical lectures, the practice of physic, or institutes of medicine. These have been drawn on regularly by historians of medicine, e.g. C.J. Lawrence, ‘Medicine as Culture: Edinburgh and the Scottish Enlightenment’ (Ph.D. thesis, University College London, 1984), G.B. Risse, New Medical Challenges During the Scottish Enlightenment. edited by C.J. Lawrence, V. Nutton and M. Neve. Vol. 1, The Wellcome Series in the History of Medicine (Amsterdam, 2005),

⁴¹The Wellcome Library in London holds at least four fairly complete sets of lectures, as well as a number of more fragmentary sets: W. Cullen, Notes Taken by Charles Blagden from Lectures on Chemistry 1765–6, MS 1922, Blagden Papers, Wellcome Library for the History and Understanding of Medicine, London, W. Cullen, Notes Taken by Will Falconer from Chemistry Lectures, 1765, MS1919–1921 Wellcome Library for the History and Understanding of Medicine, London, W. Cullen, Notes Taken from Lectures on Chemistry, n.d. [1760s], MS/MSL/79a–c Medical Society of London Wellcome Library for the History and Understanding of Medicine, London, W. Cullen, Lectures on Chemistry 1760, 1760, MS/MSL/7a–7b Medical Society of London Wellcome Library for the History and Understanding of Medicine, London.

⁴²A.L. Donovan, Philosophical Chemistry in the Scottish Enlightenment: The Doctrines and Discoveries of William Cullen and Joseph Black (Edinburgh, 1975), 31. Shaw published a series of suggested courses of chemistry in 1731 which included reference to Geoffroy's paper. P. Shaw and F. Hauksbee, An Essay for Introducing a Portable Laboratory: By Means Whereof All the Chemical Operations Are Commodiously Perform'd for the Purposes of Philosophy, Medicine, Metallurgy, and a Family (London, 1731), 41.

⁴³W. Lewis, The New Dispensatory: … Intended as a Correction, and Improvement of Quincy (London, 1753) Lewis's proposals for printing his Commercium Philosophico-Technicum of 1748 also clearly indicate his familiarity with Geoffroy's 1718 paper. W. Lewis, Proposals for Printing, by Subscription Commercicum Philosophico-Technicum (1748).

⁴⁴W. Cullen, The Plan of a Course of Chemical Lectures and Experiments to Be Given in the College of Glasgow During the Session Mdccxlviii, Glasgow, 1748, ii.

⁴⁵W. Cullen, Letter Cullen to Dr Balfour Russell, 1759, MS 156, Cullen Papers, Glasgow University Library, Glasgow.

⁴⁶W. Cullen, Dr Cullen's Table of Elective Attractions, n.d. [1750s?], NLW MS 2568E, National Library of Wales. This table includes a column for fixed air, which would date it around 1757–1759.

⁴⁷See e.g. W. Cullen, Notes Taken by Will Falconer from Chemistry Lectures, 1765, MS1919–1921 Wellcome Library for the History and Understanding of Medicine, London, MS 1921 and W. Cullen, Notes Taken from Lectures on Chemistry, n.d. [1760s], MS/MSL/79a-c Medical Society of London Wellcome Library for the History and Understanding of Medicine, London.

⁴⁹W. Cullen, Notes Taken by Charles Blagden from Lectures on Chemistry 1765–6, MS 1922, Blagden Papers, Wellcome Library for the History and Understanding of Medicine, London, Lecture 19.

⁴⁸W. Cullen, Notes Taken by Charles Blagden from Lectures on Chemistry 1765–6, MS 1922, Blagden Papers, Wellcome Library for the History and Understanding of Medicine, London, Lecture 9.

⁵⁰W. Cullen, Notes Taken from Lectures on Chemistry, n.d. [1760s], MS/MSL/79a–c Medical Society of London Wellcome Library for the History and Understanding of Medicine, London, f 66.

⁵¹W. Nicholson, A Dictionary of Chemistry. 2 vols (London: G G and J Robinson, 1795), I, 337.

⁵²W. Cullen, Notes Taken from Lectures on Chemistry, n.d. [1760s], MS/MSL/79a–c Medical Society of London Wellcome Library for the History and Understanding of Medicine, London, f 66–67.

⁵⁴W. Cullen, Notes Taken by Charles Blagden from Lectures on Chemistry 1765–6, MS 1922, Blagden Papers, Wellcome Library for the History and Understanding of Medicine, London, Lecture 44.

⁵³W. Cullen, Notes Taken by Charles Blagden from Lectures on Chemistry 1765–6, MS 1922, Blagden Papers, Wellcome Library for the History and Understanding of Medicine, London, Lecture 44.

⁵⁵S.L. Star and G.C. Bowker, Sorting Things Out: Classification and Its Consequences. (Cambridge, MA, 1999), 49.

⁵⁶William Cullen, Notes Taken by Charles Blagden from Lectures on Chemistry 1765–6, 1766,MS 1922, Blagden Papers, Wellcome Library for the History and Understanding of Medicine, London, Lecture 9.

⁵⁷William Lewis, Commercicum Philosophico-Technicum or the Philosophical Commerce of Arts: Designed as an Attempt to Improve Arts, Trades and Manufactures (London: 1763), ix.

⁵⁸William Cullen, Notes Taken by Charles Blagden from Lectures on Chemistry 1765–6, MS 1922, Blagden Papers, Wellcome Library for the History and Understanding of Medicine, London, Lecture 9.

⁶⁰W. Cullen, Notes Taken from Lectures on Chemistry, n.d. [1760s], MS/MSL/79a–c Medical Society of London Wellcome Library for the History and Understanding of Medicine, London,79a, f 5.

⁵⁹See D. Guthrie and A. Kent, ‘William Cullen M.D., and His Times’, in An Eighteenth Century Lectureship in Chemistry (Glasgow, 1950), 49–65, J.R.R. Christie, ‘Edinburgh Medicine in the Eighteenth Century: The View from the Students’, Bulletin of the Society for the History of Medicine, 19 (1976), 13–15, J. Golinski, ‘Utility and Audience in Eighteenth Century Chemistry: Case Studies of William Cullen and Joseph Priestley’, British Journal for the History of Science, 21 (1988), 1–31.

⁶⁷J. Keir, The First Part of a Dictionary of Chemistry, &C (Birmingham, 1789), 77.

⁶¹G. Taylor, ‘Unification Achieved: William Cullen's Theory of Heat and Phlogiston as an Example of His Philosophical Chemistry’, British Journal for the History of Science, 39 (2006), 477–501.

⁶²H. Guerlac, ‘The Background to Dalton's Atomic Theory’, in John Dalton and the Progress of Science, edited by D.S.L. Cardwell (Manchester: Manchester University Press, 1968), 57–91, 81.

⁶³W. Cullen, Notes Taken by Charles Blagden from Lectures on Chemistry 1765–1766, MS 1922, Blagden Papers, Wellcome Library for the History and Understanding of Medicine, London, Lecture 19.

⁶⁴We know that Cullen made at least one optimistic attempt to explain affinity in terms of the action of a Newtonian aether. See J.R.R. Christie, G.N. Cantor, and M.J.S. Hodge, ‘Ether and the Science of Chemistry’, in Conceptions of Ether: Studies in the History of Ether Theories 1740–1900 (Cambridge: Cambridge University Press, 1983), 85–110 and G. Taylor, ‘Unification Achieved: William Cullen's Theory of Heat and Phlogiston as an Example of His Philosophical Chemistry’, British Journal for the History of Science, 39 (2006), 477–501.

⁶⁵See P.E. Heimann and J.E. McGuire, ‘Newtonian Forces and Lockean Powers: Concepts of Matter in Eighteenth Century Thought’, Historical Studies in the Physical Sciences, 3 (1971), 233–306; G. Taylor, ‘Unification Achieved: William Cullen's Theory of Heat and Phlogiston as an Example of His Philosophical Chemistry’, British Journal for the History of Science, 39 (2006), 477–501; W. Nicholson, Introduction to Natural Philosophy (1790), 154–5.

⁶⁶E. Bancroft, Experimental Researches Concerning the Philosophy of Permanent Colours; and the Best Means of Producing Them, by Dying, Callico Printing, &C (London, 1794).

⁶⁸M. Crosland, ‘The Use of Diagrams as Chemical ‘Equations’ in the Lecture Notes of William Cullen and Joseph Black’, Annals of Science, 15 (1959), 75–90.

⁷⁰W. Cullen, Notes Taken by Charles Blagden from Lectures on Chemistry 1765–6, 1766,MS 1922, Blagden Papers, Wellcome Library for the History and Understanding of Medicine, London, Lecture 22.

⁶⁹The first republication of Geoffroy's table seems to have taken place in 1748, in R. Poole, A Chymical Vade Mecum (London, 1748). The British Library's copy of this volume is undated (and as a manuscript note on the flyleaf states, it is a ‘very scarce book’), although N. Moore, The History of St Bartholomew's Hospital (London, 1918), 77 dates it at 1748. Cullen himself cited the first publication of an English affinity table as W. Lewis, The New Dispensatory. … Intended as a Correction, and Improvement of Quincy (London, 1753). The claim apparently appears a set of Cullen's MS lecture notes held in City Library, Paisley—N. Sivin, ‘William Lewis (1708–1781) as a Chemist’, Chymia, 8 (1962), 63–88, 67.

⁷¹Kaiser has cited the ‘postdoc cascade’ as providing an initial framework for the ‘dispersion’ (again, I adopt Kaiser's term deliberately) of Feynman diagrams in D. Kaiser, Drawing Theories Apart: The Dispersion of Feynman Diagrams in Postwar Physics (Chicago, 2005) and D. Kaiser, Pedagogy and the Practice of Science: Historical and Contemporary Perspectives. edited by D. Kaiser (Cambridge, MA, 2005). For a graphic representation of Cullen's pedagogical pyramid, see G. Taylor, ‘Variations on a Theme: Patterns of Congruence and Divergence among 18th Century Chemical Affinity Theories’, (Ph.D. thesis, University of London, 2006), Appendix 2.

⁷²The Wellcome Library for the History and Understanding of Medicine holds sets of lecture notes taken by Blagden for both Cullen's 1766 lectures in chemistry and Black's 1767 lectures. Saunders included a printed copy of Geoffroy's and Gellert's tables with the syllabus for his chemistry lectures: W. Saunders, A Syllabus of Lectures on Chemistry ([London?]: n.d. [1766?]).

⁷³Lind's notes of Cullen's lectures are held by the British Library. W. Cullen, Chemistry Lecture Notes Taken by James Lind, n.d. [1760?], MS Add 71229–71230, British Library, London.

⁷⁴Falconer's notes of Cullen's lectures are held by the Wellcome Library, London. W. Cullen, Notes Taken by Will Falconer from Chemistry Lectures, 1765, MS1919–1921 Wellcome Library for the History and Understanding of Medicine, London.

⁷⁵M. Crosland, ‘The Use of Diagrams as Chemical ‘Equations’ in the Lecture Notes of William Cullen and Joseph Black’, Annals of Science, 15 (1959), 75–90. Edinburgh University Library has a particularly strong collection of lectures notes from Black's lectures, including some taken by Thomas Charles Hope, later to succeed Black at Edinburgh: J. Black, Lecture Notes Taken by Thomas Charles Hope on Chemistry 1782/3, MS DC 10.9.1–7 Black papers, Edinburgh University Library, Edinburgh. Another set of notes were published in facsimile form as T. Cochrane, Notes from Dr Black's Lectures on Chemistry. edited by Douglas McKie (Wilmslow, Cheshire: Imperial Chemical Industries Limited, Pharmaceuticals Division, 1966 [1767/8]).

⁷⁶Anon., An Enquiry into the General Effects of Heat & Mixture (London, 1770), iii. A number of chemists of the eighteenth century, Cullen and Black included, tended to wrongly ascribe the doctrine of affinities to Newton rather than to Geoffroy, citing Query 31 of Opticks in particular. Perhaps it is not so surprising that so many of our modern historians have followed suit.

⁷⁷Sets of Fordyce's lectures are held as G. Fordyce, Lectures on Chemistry 1786, 1786, MSS 146–48 St Thomas's Hospital, Henry Rumsey Papers, Royal College of Physicians, London, G. Fordyce, Lectures on Chemistry 1786, 1786, MS E 146 G Historical Collection Royal Society of Chemistry Library, London and G. Fordyce, Notes Taken by John Samwell from Chemistry Lectures, 1765, MS Gen 786 Glasgow University Library, Glasgow. See also W. Saunders, A Syllabus of Lectures on Chemistry ([London?]: n.d. [1766?]).

⁷⁸N.G. Coley, ‘George Fordyce MD FRS (1736–1802): Physician–Chemist and Eccentric’, Notes and Records of the Royal Society of London, 55 (2001), 395–409, 398.

⁷⁹G. Fordyce, On Compound Elective Attractions, 1759, MS 89, Cullen Papers, Glasgow University Library, Glasgow (incorrectly labelled ‘Account of Mr Slake's Paper to the Chemists at Paris on Compound Elective Attractions with notes appended by G Fordyce’.). The correspondence concerning this paper is at G. Fordyce, Five Letters to William Cullen, 1759–1774, MS 180 Cullen Papers, Glasgow University Library, Glasgow and W. Cullen, Draft Letter to George Fordyce, 1759, MS 90 Cullen Papers, Glasgow University Library, Glasgow.

⁸⁰G. Fordyce, Notes Taken by John Samwell from Chemistry Lectures, 1765, MS Gen 786 Glasgow University Library, Glasgow.

⁸¹G. Fordyce, Elements of Agriculture (Edinburgh, 1765).

⁸²Anon [G. Pearson], A Translation of the Table of Chemical Nomenclature Proposed by De Guyton, Formerly De Morveau, Lavoisier, Bertholet, and De Fourcroy with Explanations, Additions, and Alterations to Which Are Subjoined Tables of Single Elective Attraction, Tables of Chemical Symbols, Tables of the Precise Forces of Chemical Attractions’ and Schemes and Explanations of Cases of Single and Doub le Elective Attractions (London, 1799).

⁸³P-J Macquer, Dictionary of Chemistry (London, 1771), 2, 449–50.

⁸⁴Although J.L. Moilliet and B. Smith, ‘James Keir of the Lunar Society’, Notes and Records of the Royal Society of London, 22 (1967), 144–54 states that Keir left Edinburgh in 1755, the DNB claims that he left in 1757, which would have given him ample opportunity to attend Cullen's lectures.

⁸⁷G. Fordyce, Lectures on Chemistry 1786, MSS 146–48 St Thomas's Hospital, Henry Rumsey Papers, Royal College of Physicians, London, Lecture 5.

⁸⁵G. Taylor, ‘Variations on a Theme: Patterns of Congruence and Divergence among 18th Century Chemical Affinity Theories’ (Ph.D. thesis, University of London, 2006). See also G. Taylor, ‘Common Grounds: Variation and Consensus in 18th Century British Theories of Chemical Affinity’ (forthcoming).

⁸⁶See e.g. W. Cullen, Notes Taken by Charles Blagden from Lectures on Chemistry 1765–6, MS 1922, Blagden Papers, Wellcome Library for the History and Understanding of Medicine, London, lecture 25.

⁸⁸G. Fordyce, Elements of Agriculture (Edinburgh: 1765). Fordyce's affinity theory is clearly evident throughout this work which ran to five editions, the last of which was published in 1796.

⁸⁹P. Galison and A. Assmus, ‘Artificial Clouds, Real Particles’, in The Uses of Experiment: Studies in the Natural Sciences, edited by D. Gooding, T.J. Pinch and S. Schaffer (Cambridge, 1989), 225–74, 266. See also P. Galison, Image and Logic: A Material Culture of Microphysics (1997), in particular ch. 2.

⁹⁰These ‘supplementary components’ of affinity theories are discussed at length in chapter 4 of G. Taylor, ‘Variations on a Theme: Patterns of Congruence and Divergence among 18th Century Chemical Affinity Theories’ (Ph.D. thesis, University of London, 2006).

⁹¹A. Simões ‘Charles Alfred Coulson and the Crafting of Science’, British Journal for the History of Science, 37 (2004), 299–342, 300.

⁹²G. Taylor, ‘Variations on a Theme: Patterns of Congruence and Divergence among 18th Century Chemical Affinity Theories’ (Ph.D. thesis, University of London, 2006) and G. Taylor, ‘Common Grounds: Variation and Consensus in 18th Century British Theories of Chemical Affinity’ (forthcoming).

⁹³A.M. Duncan, Laws and Order in Eighteenth-Century Chemistry (Oxford, 1996), 116.

⁹⁴W. Lewis, Commercicum Philosophico-Technicum or the Philosophical Commerce of Arts: Designed as an Attempt to Improve Arts, Trades and Manufactures (London, 1763), v.

⁹⁵W. Cullen, Chemistry Lecture Notes Taken by James Lind, n.d. [1760?], MS Add 71229–71230, British Library, London, f 143r. The explanation given in W. Cullen, Rough Notes taken by David Carmichael from Chemistry Lectures, 1757, MS 12, Cullen Papers, Royal College of Physicians Edinburgh Library, Edinburgh, f 97 matches this almost verbatim; it is sufficiently close a match to suggest that the two MSS are from the same course, which would date the British Library MS at 1757.

⁹⁶For a more detailed explanation of the logical common ground, see G. Taylor, ‘Variations on a Theme: Patterns of Congruence and Divergence among 18th Century Chemical Affinity Theories, (Ph.D. thesis, University of London, 2006) and G. Taylor, ‘Common Grounds: Variation and Consensus in 18th Century British Theories of Chemical Affinity’ (forthcoming).

⁹⁷J. Elliot, Elements of the Branches of Natural Philosophy Connected with Medicine (1782), 131.

⁹⁸For a detailed survey of the variations between individuals’ affinity theories, see G. Taylor, ‘Variations on a Theme: Patterns of Congruence and Divergence among 18th Century Chemical Affinity Theories’ (Ph.D. thesis, University of London, 2006).

⁹⁹D. Kaiser, Drawing Theories Apart: The Dispersion of Feynman Diagrams in Postwar Physics (Chicago, 2005), 93–101.