¹ August W. Hofmann (1818–1892). For an acccount of his period at the College see Bentley, J., ‘The Chemical Department of the Royal School of Mines: Its Origins and Development under A.W. Hofmann’, Ambix, (1970), 17, pp. 153–181.CrossRefGoogle Scholar For details of the lecture see the Diary of Herbert McLeod, Imperial College (University of London) Archives, entry for 4 December 1863. Herbert McLeod (1841–1923) was assistant chemist at the Royal College of Chemistry. For an account of his life see [horpe], T.E.T., ‘Herbert McLeod, 1841–1923, Proc. Roy. Soc. (1924), 105A, pp. x–xi.Google Scholar He kept a daily diary from 1 January 1860 until three days before his death. His Grandson has placed this on temporary loan in Imperial College Archives. The diary for the 1860s has been published in James, Frank A.J.L., Chemistry and Theology in mid-Victorian London: The Diary of Herbert McLeod, 1860–1870, London, 1987.Google Scholar References to the diary hereafter will be to date only.

² Victoria (1840–1901), later Empress of Germany.

³ Both these positions can be discerned in the history of spectroscopy that was written in the 1860s. See James, Frank A.J.L., ‘The Creation of a Victorian Myth: The Historiography of Spectroscopy’, Hist. Sci. (1985), 23, pp. 1–24.CrossRefGoogle Scholar

⁴ Gooding, David, ‘“He who proves discovers”: John Herschel, William Pepys and the Faraday Effect’, Notes Rec. Roy. Soc. Lond. (1985), 39, pp. 229–244CrossRefGoogle Scholar provides a parallel example, but there the precursors took no part in developing the discovery of the magneto-optical effect.

⁵ For these see James, Frank A.J.L., ‘The Debate on the Nature of the Absorption of Light, 1830–1835: A Core-set Analysis’, Hist. Sci (1983), 21, pp. 335–368CrossRefGoogle Scholar and ‘The Study of Spark Spectra, 1835–1859, Ambix, (1983), 30, pp. 137–162, respectively.Google Scholar

⁶ Daniell, J.F., An Introduction to the Study of Chemical Philosophy, 2nd edn, London, 1843, especially pp. 336, 385 and 388.Google ScholarMiller, W.A., ‘Experiments and observations on some cases of lines in the prismatic spectrum produced by the passage of light through coloured vapours and gases, and from certain coloured flames’, Phil. Mag. (1845), 27, pp. 81–91.Google Scholar

⁷ John Hall Gladstone (1827–1902). He studied chemistry under Liebig at the University of Giessen 1847–1848. For an account of his life see [horpe], T.E.T., ‘John Hall Gladstone, 1827–1902’, Proc. Roy. Soc. (1905), 87, pp. 188–192.Google Scholar

⁸ Gladstone, J.H., ‘On the use of the prism in qualitative analysis’, Quart. J. Chem. Soc. (1858), 10, 79–91, p. 79.CrossRefGoogle Scholar

⁹ See also Gladstone, J.H., ‘On Chromatic Phenomena Exhibited by Transmitted Light’, Proc. Roy. Inst. (1857), 2, pp. 336–343.Google Scholar

¹⁰ Crookes, William (1832–1919). The standard biography of Crookes remains E.E.F. D'Albe, The life of Sir William Crookes, London, 1923.Google Scholar

¹¹ Crookes, W., ‘Examination of the spectrum produced by coloured flames’Google Scholar, in D'Albe, , op. cit. (10) pp. 26–27.Google Scholar This according to D'Albe (p. 27) is taken from an old notebook of Crookes's dated April 1854.

¹² Crookes, W., ‘Photographic researches on the spectrum—the spectrum camera and some of its applications’, J. Photogr. Soc. (1856), 2, pp. 292–295.Google Scholar

¹³ Gladstone, to Crookes, , 4 02 1857Google Scholar, in D'Albe, , op. cit. (10) pp. 37–38.Google Scholar Gladstone mentioned Crookes's work in his Royal Institution Discourse, op. cit. (9) p. 336 and in op. cit. (8) p. 80 where he added a rider suggesting that the use of emission spectra would be of ‘limited and difficult application’.

¹⁴ For a detailed treatment of this work see James, Frank A.J.L., ‘The establishment of spectro-chemical analysis as a practical method of qualitative analysis, 1854–1861’, Ambix, (1983), 30, pp. 30–53, 30–32.CrossRefGoogle Scholar

¹⁵ Robert Wilhelm Bunsen (1811–1899). Bunsen had previously taught chemistry at Göttingen, Cassel, Marburg and Breslau (now Wroclaw).

¹⁶ Rowlandson Cartmell (d. 1888) was a student at the Royal Colige of Chemistry 1847–48. Later he became an analytical chemist to a brewery in Burton on Trent. See Register of the Associates and Old Students of the Royal College of Chemistry…, London, 1896, p. 34.Google Scholar

¹⁷ See Kirchhoff, G.R., ‘Untersuchungen über das Sonnenspectrum und die Spectren der Chemischen Elemente’, Abh. Königl. Akad. Wiss. Berlin, (1861), pp. 63–95; (1862), pp. 227–240.Google Scholar Translated into English (by Roscoe, H.E.) as Researches on the solar spectrum, and the spectra of the chemical elements, 2 vols, Cambridge, (1862–1863), I, p. 6Google Scholar, where he says that Bunsen directed Cartmell.

¹⁸ Cartmell, R., ‘On a photochemical method of recognizing the non-volatile alkalies and alkaline earths’, Phil. Mag. (1858), 16, pp. 328–333.CrossRefGoogle ScholarBunsen, R.W., ‘Löthrohrversuche’, Ann. Chim. Pharm. (1859), 111, pp. 257–276CrossRefGoogle Scholar; translated into English as ‘Blowpipe experiments’, Phil. Mag. (1859), 18, pp. 513–521.Google Scholar

¹⁹ See James, , op. cit. (14) pp. 34–35.Google Scholar

²⁰ Gustav Robert Kirchhoff (1824–1887). Bunsen and Kirchhoff met when they were both teaching at the University of Breslau. Bunsen was later able to ensure, in 1854, that Kirchhoff was appointed to the post of professor of physics at Heidelberg when it became vacant. See Jungnickel, C. and McCormmach, R., The Intellectual Mastery of Nature: Theoretical Physics from Ohm to Einstein, Volume 1: The Torch of Mathematics 1800–1870, Chicago, 1986, pp. 288–290.Google Scholar

²¹ Ostwald, W., Klassiker der Exakten Wissenschaften Nr 72, Leipzig, 1895, pp. 71–73.Google Scholar This is an account of a conversation between Ostwald and Bunsen about the development of the latter's work on spectro chemistry. In it this account of the origin of Bunsen and Kirchhoff's collaboration is given.

²² Bunsen, R.W. and Kirchhoff, G.R., ‘Chemische Analyse durch Spectralbeobachtungen’, Pogg. Ann. (1860), 110, pp. 160–189.Google Scholar

²³ Bunsen, R.W. and Kirchhoff, G.R., ‘Chemical Analysis by spectrum-observations’, Phil. Mag. (1860), 20, pp. 89–109.Google Scholar The spectra they described in their paper were those of sodium, potassium, lithium, strontium, calcium and barium.

²⁴ Kirchhoff, G.R., ‘Ueber das Sonnenspecktrum’, Verhandl. Nat. Med. Ver. Heidelb. (1859), pp. 251–255, 253.Google Scholar

²⁵ Kirchhoff, G.R., ‘Ueber das Zusammenhang zwischen Emission und Absorption von Licht und Wärme’, Berlin Monatsber. (1859), pp. 783–787.Google Scholar

²⁶ Helmholtz, to Thomson, , 15 11 1859Google Scholar, Glasgow University Library, Kelvin Papers H16.

²⁷ Hermann von Helmholtz (1821–1894) had previously taught physiology at Königsberg and Bonn.

²⁸ Helmholtz, H. v., Ueber die Wechselwirkung der Naturkräfte und die darauf bezüglichen neusten Ermittelungen der Physik, Königsberg, 1854Google Scholar translated into English as ‘On the Interaction of Natural Forces’, Phil. Mag. (1856), 9, pp. 489–518.Google Scholar

²⁹ Clerke, A.M., A Popular History of Astronomy during the Nineteenth Century, 3rd edn, London, 1893, p. 378.Google ScholarMerz, J.T., A History of European Thought in the Nineteenth Century, 4 volumes, Edinburgh, (1904–1912), 2, pp. 358–359.Google ScholarDeVorkin, D.H., An Astronomical Symbiosis: Stellar Evolution and Spectral Classification (1860–1910), University of Leicester Ph.D. thesis, 1978.Google Scholar

³⁰ H.E. Roscoe (1833–1915), Professor of Chemistry at Owens College Manchester. For an account of his life see Roscoe, H.E., The Life and Experiences of Sir Henry Enfield Roscoe, London, 1906.CrossRefGoogle Scholar He studied chemistry under Bunsen, 1853–1854, and then collaborated with him on an extensive study of photochemical phenomena.

³¹ Friedrich Wilhelm Dupré (before 1835–1908) and August Dupré (1835–1907). Both brothers had studied chemistry under Liebig at Giessen and under Bunsen at Heidelberg before coming to London in 1855 to work for W. Odling at Guy's Hospital Medical School. For biographical details of August see Hake, H.W., ‘August Dupré, 1835–1907’, Proc. Roy. Soc. (1908), 80, pp. xiv–xviii.Google Scholar

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³³ Bennet, J.A., The Celebrated Phaenomena of Colours, Cambridge, 1984.Google Scholar

³⁴ McLeod Diary, 2 January 1861.

³⁵ Ibid., 4 January 1861.

³⁶ Ibid., 5 January 1861.

³⁷ Ibid., 7 January 1861.

³⁸ Ibid., 8 January 1861.

³⁹ For example, on 28 March 1861 McLeod visited three instrument makers in search of a suitable spectroscope which could be constructed. However, it was not until 27 May 1861 that he placed an order with Slater. There then followed a good number of visits, adjustments, additions etc., so that it was not until 1 August 1861 that McLeod could declare that ‘It did splendidly’.

⁴⁰ Crookes, to Williams, , 7 03 1861Google Scholar, in James, Frank A.J.L., ‘The Letters of William Crookes to Charles Hanson Greville Williams 1861–2: The Detection and Isolation of Thallium’, Ambix, (1981), 28, pp. 131–157, letter 8.CrossRefGoogle Scholar

⁴¹ Crookes, to Williams, , 9 07 1861Google Scholar, ibid., letter 20.

⁴² International Exhibition 1862. Medals and Honourable Mentions awarded by the International Juries, 2nd edn, London, 1862, class xiii, pp. 29–30.Google Scholar

⁴³ Ibid., p. 29.

⁴⁴ Ibid., 29–30 and The International Exhibition of 1862. The Illustrated Catalogue of the Industrial Department. British Division, 2 volumes, London, 1862, 2, section xiii, pp. 16 and 35.Google Scholar

⁴⁵ Crookes, to Williams, , 2 03 1861Google Scholar, in James, , op. cit. (40), letter 6.Google Scholar

⁴⁶ For the cost of Browning's spectroscope see The International Exhibition, op. cit. (44) p. 35.Google Scholar McLeod's quarterly salary was £23.19.2 (see McLeod's Diary, 2 April 1861).

⁴⁷ Miller collaborated with William Huggins on an extended study of stellar spectra, ‘On the spectra of some fixed stars’, Phil. Trans. (1864), 154, pp. 413–436Google Scholar, while Gladstone continued with his spectral studies, ‘On the emission and absorption of rays of light by certain gases’, Rep. Brit. Ass. (1861), part 2, p. 79.Google Scholar

⁴⁸ Bunsen, R., ‘Ueber ein neues, dem Kalium nahestehendes Metall’, J. Prak. Chem. (1860), 80, pp. 477–480.Google Scholar

⁴⁹ Ibid., pp. 478–479.

⁵⁰ Ibid., p. 479.

⁵¹ Bunsen, to Roscoe, , 10 04 1860Google Scholar, Deutsches Museum München, Handscriften number 932. Translated into English in Roscoe, H.E., ‘Bunsen Memorial Lecture’, J. Chem. Soc. (1900), 77, pp. 513–554, 531.CrossRefGoogle Scholar

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⁵³ Bunsen, to Roscoe, , 6 11 1860Google Scholar, DMHS 936. Partly translated into English in Roscoe, , op. cit. (51), p. 532.Google ScholarBunsen, R.W. and Kirchhoff, G.R., ‘Chemische Analyse durch Spectralbeobachtungen’, Pogg. Ann. (1861), 113, pp. 337, 381.Google Scholar Translated into English as ‘Chemical Analysis by spectrum observations’, Phil. Mag. (1861), 22, pp. 329–349, 498–510.Google Scholar Since the characteristic line of the spectrum of this new element was in the blue Bunsen derived the name from ‘ceasia’ used in Aulus Gellius, Noctes Atticae, 2, 26 to designate the blue of a clear sky.

⁵⁴ Bunsen, to Roscoe, , 6 11 1860Google Scholar, DMHS 936. Bunsen, R. ‘Ueber ein fünftes der Akaligruppe angehörendes Element’, J. Prak. Chem. (1861), 83, pp. 198–200Google Scholar translated into English as ‘On a fifth element belonging to the alkali group’, Chem. News, (1861), 3, p. 357.Google Scholar

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⁵⁸ Ibid.

⁵⁹ Crookes, to Williams, , 5 03 1861Google Scholar, ibid., letter 7, and James, op. cit. (56).Google Scholar

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⁶¹ Ferdinand Reich (1799–1882). Professor of Physics at Freiberg.

⁶² Heironymous Richter (1824–1898) was a metallurgical chemist at the Freiberg School of Mines of which he later became director.

⁶³ Reich, F. and Richter, H., ‘Vorläufige Notiz über ein neues Metall’, J. Prak. Chem. (1863), 89, p. 441CrossRefGoogle Scholar, translated into English as ‘Preliminary Notice of a New Metal’, Chem. News, (1863), 8, p. 123Google Scholar and ‘Ueber das Indium’, J. Prak. Chem. (1863), 90, pp. 172–176Google Scholar, translated into English as ‘On Indium’, Chem. News, (1863), 8, pp. 280–281.Google Scholar

⁶⁴ Karpenko, V., ‘The Discovery of Supposed New Elements: Two Centuries of Error’, Amhix, (1980), 27, pp. 77–102.Google Scholar

⁶⁵ These were, respectively, Wasmium by Bahr, J.F., ‘Om en ny metalloxid’, Öfver. Kongl. Veten. Acad. Förhandlingar, (1862), 19, pp. 415–423Google Scholar; a nameless metal by Chandler, C.F., ‘A New Metal in the Native Platinum of Rogue River, Oregon’, Am. J. Sci. (1862), 33, pp. 351–352CrossRefGoogle Scholar; Pantogen by Hinrichs, G., Programmder Atommechanik oder die Chemie eine Mechanik der Panatome, Iowa City, 1867Google Scholar; Dianium by von Kobell, F., ‘Ueber eine eigenthümliche Säure, Diansäure, in der Gruppe der Tantal-und Niobverbindungen’, Gel. Am. her. Mitgl. Königl. Baier. Akad. Wiss. (1860), 50, pp. 377–389.Google Scholar For the two British ‘elements’ see below.

⁶⁶ Bennett, , op. cit. (33)Google Scholar and McLeod Diary index entry under ‘Spectroscopy’.

⁶⁷ Crookes, W., ‘On the Existence of a New Element, probably of the Sulphur Group’, Chem. News, (1861), 3, pp. 193–194.Google Scholar

⁶⁸ See, for example, Frankland, E., ‘On the combustion of hydrogen and carbonic oxide in oxygen under great pressure’, Proc. Roy. Soc. (1868), 16, pp. 419–422.CrossRefGoogle Scholar

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⁷¹ Crookes, W., ‘Further Remarks on the Supposed new Metalloid’, Chem. News, (1861), 3, p. 303.Google Scholar

⁷² There are many references to Crookes's isolation of metallic thallium by January 1862; the earliest is Crookes, to Miller, W.A., 12 06 1862Google Scholar, Science Museum, London, MS 429, printed in Crookes, W., ‘On the Discovery of the Metal Thallium’, Phil. Mag. (1863), 26, pp. 55–63, 57.CrossRefGoogle Scholar In Crookes to the Council of the Royal Society, 21 May 1862, SM MS 429, Crookes refers to thallium thus: ‘It appears to have the properties of a heavy metal’.

⁷³ C.A. Lamy (1820–1878). Later (1865) professor of chemistry at the École Centrale des Arts et Manufactures in Paris. See Partington, J.R., A History of Chemistry, 4 volumes, London, (1961–1970), 4, p. 883.Google Scholar

⁷⁴ Séance du 2 Mai, Mem. Soc. Imp. Sci. Agr. Arts. Lille, (1862), 9, pp. vii–ix.Google Scholar

⁷⁵ Séance du 16 Mai, ibid., pp. ix–x.

⁷⁶ Lamy, C.A., ‘De l'existence d'un nouveau métal, le thallium’, Comptes Rendus, (1862), 54, pp. 1255–1258.Google Scholar Translated into English as ‘On the new metal thallium’, Chem. News, (1862), 6, pp. 29–30.Google Scholar

⁷⁷ For a full discussion of this episode see James, , op. cit. (56).Google Scholar

⁷⁸ For some nationalistic comments see ‘Spectroscope’ and ‘An English Chemist’, Chem. News, (1862), 6, p. 119Google Scholar; ‘Je Veux de Bonne Guerre’, ibid., p. 131. I have been unable to identify the authors of these letters.

⁷⁹ Charles Hanson Greville Williams (1829–1910). For a short account of his life see Church, A.H., ‘Greville Williams, 1829–1910’, Proc. Roy. Soc. (1911), 85, pp. xvii–xx.Google Scholar

⁸⁰ See the letters contained in James, , op. cit. (40).Google Scholar

⁸¹ Crookes, to Williams, , 16 03 1861Google Scholar, ibid., letter 12.

⁸² Crookes, to Williams, , 13 04 1861Google Scholar, ibid., letter 17.

⁸³ Ibid.

⁸⁴ George Frederick Ansali (1826–1880). See DNB for an account of his life.

⁸⁵ McLeod diary, 8 April 1868.

⁸⁶ A.H. Church (1834–1915). He was at the Royal College of Chemistry from 1851 to 1853 when Crookes was an assistant there.

⁸⁷ Church, A.M., ‘Micro-Spectroscope Investigations’, Int. Obs. (1866), 9, pp. 291–292.Google ScholarSvanberg, L., ‘Nya jordarter i zinkoner’, Öfver. Kongl. Veten. head. Förhandlingar, (1845), 2, pp. 34–37.Google Scholar

⁸⁸ Church to Crookes, , 6 03 1869Google Scholar, in ‘A New Element Accompanying Zirconium discovered by means of spectrum analysis’, Chem. News, (1869), 19, pp. 121–123, 121.Google Scholar

⁸⁹ H.C. Sorby (1826–1908). See Higham, H., A very scientific gentleman: The major achievements of Henry Clifton Sorby, Oxford, 1963.Google Scholar

⁹⁰ ‘A new element’, op. cit. (88), p. 121.Google Scholar

⁹¹ Church to Crookes, 6 March 1869, Ibid..

⁹² Ibid.

⁹³ Church, A.M., ‘The new earth in some zircons’, Chem. News, (1869), 19, p. 142.Google Scholar P.J. Butler, ‘Jargonia’, ibid., p. 210; this supported Sorby.

⁹⁴ Sorby, H.C., ‘Further researches on Jargonium and the Ceylon Jargon’, Chem. News, (1869), 19, p. 205Google Scholar, ‘On Jargonium: A new elementary substance associated with zirconium’, ibid., (1869), 20, pp. 7–9, ‘On Jargonia’, ibid., p. 104.

⁹⁵ Higham, , op. cit. (89), p. 98.Google ScholarSorby, H.C., ‘On some remarkable compounds of zirconia and the oxides of uranium’, Proc. Roy. Soc. (1870), 18, pp. 197–207.Google Scholar

⁹⁶ Edward Frankland (1825–1899). See West, M. and Colenso, F. (eds), Sketches from the Life of Edward Frankland, London, 1902Google Scholar and Russell, C.A., Lancastrian Chemist: The Early Years of Sir Edward Frankland, Milton Keynes, 1986.Google Scholar

⁹⁷ J.N. Lockyer (1836–1920). See Lockyer, T.M. and Lockyer, W.L., Life and work of Sir Norman Lockyer, London, 1928Google Scholar and Meadows, A.J., Science and controversy: A biography of Sir Norman Lockyer, founder editor of Nature, London, 1972.Google Scholar

⁹⁸ Ibid., pp. 58–59.

⁹⁹ Ibid., p. 60.

¹⁰⁰ For example ibid., p. 19.

¹⁰¹ Certificate of Election in the RS MS.

¹⁰² Lockyer, J.N., ‘The Story of Helium’, Nature, (1896), 53, pp. 319–322, 342–346.CrossRefGoogle Scholar

¹⁰³ For example, William Thomson mentioned it in his Presidential Address to the 1871 British Association meeting held in Edinburgh, Rep. Brit. Ass. (1871), pp. lxxxiv–cv, xciv.Google Scholar

¹⁰⁴ Lockyer, , op. cit. (102)Google Scholar. This subject is outside the scope of this paper and will form the topic of a future paper.

¹⁰⁵ Diary of Queen Victoria, 23 March, 1865, Windsor Castle Royal Archive.