Science,Scientific Careers and Social Exchange in London: The Diary of Herbert McLeod,1885–1900

Imperial College London Archives, Herbert McLeod Diary (1860–1923). The first eleven years of the diary have been transcribed; see James Frank A. J. L. , (ed.), Chemistry and theology in mid-Victorian London: The diary of Herbert McLeod, 1860–70 (London and New York: Mansell microfiche, 1987).

See Gay Hannah , “‘Pillars of the College’: Assistants at the Royal College of Chemistry 1846–71”, Ambix, xlvii (2000), 135–69; “Science and opportunity in London, 1871–85: The diary of Herbert McLeod”, History of science, xli (2003), 2003–58; “‘The Declaration of Students of the Natural and Physical Sciences’, revisited: Youth, science, and religion, in mid-Victorian Britain”, in Sweet William Feist Richard , (eds), Religion and the challenges of science (Aldershot, 2007), 19–37; and “Technical assistance in the world of London science, 1850–1900”, Notes and records of the Royal Society, lxii (2008), 2008–75.

The college was situated at Cooper's Hill near Egham and was within easy reach of London by train. The site is now occupied by a campus of Brunel University. McLeod was first appointed in 1871 as professor of experimental science, but when W. N. Stocker was appointed professor of physics in 1883 McLeod became professor of chemistry. In 1901 McLeod and several other of the academic staff lost their jobs when the college cut back its offerings. The college closed permanently in 1906. McLeod was appointed Director of the Royal Society Catalogue of Scientific Papers in 1901.

Trades shops were a major site for scientific exchange. This is discussed in Gay , op. cit. (ref. 2, 2008). McLeod's connections to people in the scientific trades will not be discussed further here.

Gay , op. cit. (ref. 2, 2003).

Secord James A. , “Knowledge in transit”, Isis, xcv (2004), 654–72; quotation below, p. 660.

Morus Iwan , “Replacing Victoria's scientific culture”, Interdisciplinary studies in the long nineteenth century, ii (2006); www.19.bbk.ac.uk.

Morus , op. cit. (ref. 7), 8.

See, for example, Fyfe Aileen Lightman Bernard , (eds), Science in the marketplace: Nineteenth-century sites and experiences (Chicago, 2007). While it is not necessary to share the views held by historical actors, T. H. Huxley's notions on hierarchy have been too easily dismissed in some of these essays (see, for example, Fyfe and Lightman, introduction, p. 3).

See Secord James A. , “How scientific conversation became shop talk”, in Fyfe and Lightman, op. cit. (ref. 9), 23–53. Secord describes how much of what once was deemed polite scientific conversation changed its colours and came to be seen as shop talk, as new power brokers entered society late in the nineteenth century. However, scientific topics remained commonplace in day-to-day conversation. In McLeod's case he engaged both in polite scientific conversation and in much private technical discussion.

Secord , op. cit. (ref. 6), 671.

By modernism, I am thinking of a range of post-Romantic ideas on human identity and sensibility beginning roughly with Nietzsche and ending with postmodernism.

In some quarters today we hear complaints that young people spend too much time consuming the products of science (video games, downloading and listening to/watching iPods, talking on mobile phones, etc.) and not enough time consuming/studying mathematics, science or engineering. There is concern over where the producers of tomorrow will come from. Governments, in turn, struggle to restore equilibrium by finding ways of encouraging future producers into technological areas of higher education. I use the verb ‘diffuse’ not ‘defuse’ since resentment never vanishes, it recycles in new forms.

Much existing literature on the type of scientific naturalism promoted by some of McLeod's contemporaries portrays it as radical, and focuses on ways in which it was used successfully to contest older ways of thinking. See, for example, Turner Frank M. , Between science and religion: The reaction to scientific naturalism in late Victorian England (New Haven, 1974) and Contesting cultural authority: Essays in Victorian intellectual life (Cambridge, 1993). A good overview of how some of the science/naturalism/theology/religion debates are viewed today can be found in Bernard Lightman, “Victorian sciences and religions: Discordant harmonies”, in Brooke John Hedley Osler Margaret J. van der Meer Jitse M. (eds), Science in theistic contexts: Cognitive dimensions (Osiris, xvi (2003)), 343–66. McLeod, while seriously religious, played only a marginal role in these debates. He sided with his friend Arthur Balfour who, as Lightman points out, opposed any two-sphere account in which science was to reside together with naturalism (at least with how T. H. Huxley construed it) in one sphere, and religion in the other. For McLeod, science and religion could not easily be separated. The élite cultural spaces challenged by people such as Huxley have certainly shrunk, but they have done so for a multitude of reasons.

See Prout W. , “On the relation between the specific gravities of bodies in their gaseous state and the weight of their atoms”, Annals of philosophy, vi (1815), 321, and vii (1816), 111. For more on the outcome of Prout's Hypothesis see Knight David , Atoms and elements: A study of theories of matter in England in the nineteenth century (London, 1967), chap. 7; and Brock W. H. , From protyle to proton: William Prout and the nature of matter, 1785–1985 (Bristol, 1985). For Rayleigh see Gavroglu Kostas , “Strutt, John William, third Baron Rayleigh (1842–1919)”, Oxford dictionary of national biography (Oxford, 2004).

Atomic weights are experimentally determined weights of atoms relative to some arbitrary standard. If hydrogen is assumed to have an atomic weight of one then, if Prout's Hypothesis were true, oxygen should have one of sixteen. Prout's Hypothesis was finally abandoned after isotopes were discovered.

Argon was the first to be isolated: Rayleigh Lord Ramsay William , “Argon, a new constituent of the atmosphere”, Proceedings of the Royal Society, lvii (1895), 265–87. The various means of producing pure nitrogen are discussed in some detail in this paper. William Crookes provided spectroscopic data for Rayleigh and Ramsay. Ramsay had connected Rayleigh's work on nitrogen with the 1783 experiment of Henry Cavendish in which ‘dephlogisticated air’ (largely nitrogen) and oxygen were combined using sparks from frictional electricity. Cavendish found there was a gaseous residue in the nitrogen that would not react (with oxygen). Ramsay isolated argon from atmospheric nitrogen by low-temperature distillation and fractionation; further fractionation and spectroscopic analysis led to the separation of krypton, neon and xenon. For Ramsay see Watson K. D. , “Ramsay, Sir William (1852–1916)”, Oxford dictionary of national biography (Oxford, 2004) and for an account of the discovery of the noble gases by one of Ramsay's co-workers see M. W. Travers, The discovery of the rare gases (London, 1928).

McLeod also noted the politicking that went on at the Government Grants Committee at the Royal Society before a grant of £400 was awarded to Dewar in 1894 (diary entries on grant, April and May 1894). For Dewar at the Royal Institution see Brock William H. , “Exploring the hyperarctic: James Dewar at the Royal Institution”, in James Frank A. J. L. (ed.), “The common purposes of life”: Science and society at the Royal Institution of Great Britain (Aldershot, 2002), 169–90.

In 1894 when Rayleigh and Ramsay announced the discovery of argon, Dewar ridiculed the claim, stating that the new gas was simply an allotrope of nitrogen. Ramsay retaliated for this and other slights by challenging Dewar for the presidency of the Chemical Society in 1897, even after Dewar had been nominated by the council. The competitive tension between these two men will have contributed to Dewar's refusal to supply Ramsay with liquid air. See Brock , op. cit. (ref. 18), 183–5. See also Davies Mansell , “William Hampson (1854–1926): A note”, The British journal for the history of science, xxii (1989), 63–73. Hampson was highly gifted. He had studied classics, was called to the Bar, and later qualified as a physician. Clearly he also had considerable engineering skills. Like Robert Lennox, the designer of Dewar's apparatus, he made use of the Joule-Thomson effect. But Hampson's apparatus was simpler in design and possibly more efficient. He took out a patent in 1895 and, by the late 1890s, was able to produce a few litres of liquid air per hour.

For Ramsay's Nobel Prize lecture see Nobelprize.org. Arthur and Leo Brin (Brin Frères et Cie.) developed their process in France. The Brin Oxygen Company produced oxygen in Britain under patent from 1886. Later the company became the British Oxygen Company. Barium monoxide was made to react with oxygen from the air. The product, when heated to about 870°C, releases the oxygen taken up at lower temperatures. The system was sometimes metaphorically referred to as the ‘barium oxide lung’. McLeod was on the chemical jury for the Inventions Exhibition (see below).

The preparation of very pure samples of the elements and the determination of atomic weights was an obsession before the discovery of isotopes (see Knight Brock , op. cit. (ref. 15)). The first determination of the atomic weight of oxygen was by J. B. Dumas in 1842 but others followed. See, for example, Gay Hannah , “The chemical philosophy of Theodore W. Richards”, Ambix, xliv (1997), 19–38. Richards, while a student of Josiah Cooke at Harvard, determined the atomic weight of oxygen relative to hydrogen as one. His ratio was 15.869 ( Cooke J. P. Richards T. W. , “Atomic weights of oxygen and hydrogen”, Journal of the American Chemical Society, x (1888), 81 and 191). Rayleigh published a series of results; for one published in the same year as Cooke and Richards see Rayleigh Lord , “On the relative densities of hydrogen and oxygen”, Proceedings of the Royal Society, xliii (1887–88), 356–63. That year his ratio was 15.912; later measurements gave a slightly lower ratio. Richards won the 1914 Nobel Prize for chemistry for his work on atomic weight.

Helium was first detected extraterrestrially in the sun's chromosphere by P. J. C. Janssen who was a member of an eclipse expedition to India in 1868. Later J. N. Lockyer and E. Frankland interpreted the spectroscopic data, confirmed the existence of a new element and named it helium. In 1895 Ramsay, prompted by the American geochemist W. F. Hillebrand who had noted some new lines in the spectra of gases occluded in the mineral cleveite, isolated helium from the mix. In 1900 he separated helium from some atmospheric neon using low temperature liquefaction and distillation. When Ramsay presented this latter work to the Royal Society, mentioning the earlier identification of helium, McLeod did something typical of him. He went to the literature and found that Ramsay had not cited the earliest mention of terrestrial helium, as he had claimed. Ramsay received the 1904 Nobel Prize for chemistry for his work on the noble gases. In the same year Lord Rayleigh was awarded the Nobel Prize for physics.

On 4 June 1896 Lockyer gave a paper at the Royal Society in which he discussed work on gases occluded in minerals, and the search for new elements. At the same meeting Dewar and J. A. Fleming spoke on a different topic, namely on the properties of bismuth and mercury at very low temperatures. This was part of a larger study of the electrical and magnetic behaviour of metals at low temperatures. Relatedly, and during the same period, Edward Matthey, of the metal refiners Johnson & Matthey, presented several papers on the purification of bismuth (removal of arsenic and antimony). McLeod mentions attending at all these papers.

For a brief description see McLeod Herbert , “Note on a sunshine recorder”, Nature, 5 February 1885, 319–20.

At the Geological Society McLeod was often the guest of the paleontologist H. G. Seeley (Harry Govier Seeley, FRS (1839–1909) was professor of geography and geology at King's College London). Occasionally Seeley invited him also to Geological Club dinners (for example, 24 May 1899 when he sat between Seeley and Archibald Geikie) and to his home where McLeod enjoyed looking at his fossil collection (for example, 18 February 1892). Sometimes McLeod complained about the regular meetings at the Royal Society; for example, “too many papers were read too rapidly” (diary, 18 June 1885). Papers at the Royal Society were very varied. For example, on 21 January 1886, McLeod listened to F. Galton on “Family likeness in stature”, to W. Crookes “On radiant matter spectroscopy”, and to Lord Rayleigh “On the Clark Cell as a standard of EMF”. Like many others, McLeod had been to Galton's anthropometric laboratory in South Kensington to be ‘measured’.

For more on the role of the British Association and its influence on the lives of practising scientists, see Brock W. H. , “Advancing science: The British Association and the professional practice of science”, in MacLeod Roy Collins Peter (eds), The parliament of science: The British Association for the Advancement of Science, 1831–1981 (Northwood, Middlesex, 1981), chap. 3.

Diary, 18 November 1885. Taking borings in the Nile Delta was a major geological project of the period which received much funding. Judd reported trying, but not yet succeeding, to reach the rocky floor of the delta. Ramsay was not yet a Fellow of the Royal Society. He and his assistant were beginning work on critical phenomena in liquids and their paper was communicated by G. G. Stokes. See Ramsay William Young Sydney , “On evaporation and dissociation: Part one”, Proceedings of the Royal Society, xxxix (1885), 228–9. Charles Edward Groves, FRS (1841–1920) was a friend of McLeod's from his student days at the Royal College of Chemistry. He was a lecturer at Guy's Hospital Medical School and editor of the Chemical Society journal. There are many mentions of both Groves and Ramsay in McLeod's diary including their sitting together and chatting at various dinners. The Chemical Club was a dining club for chemists. For this and other clubs see Gay Hannah Gay John W. , “Brothers in science: Science and fraternal culture in nineteenth-century Britain”, History of science, xxxv (1997), 1997–53.

Gladstone John Hall , FRS (1827–1902) had been something of a mentor to the younger McLeod. Both men were very religious though differing in their approach. Gladstone was an evangelical ‘low-church’ Anglican while McLeod was ‘high-church’. Gladstone was a promoter of the Young Men's Christian Association and of the Christian Evidence Society. He was also active in the Liberal Party. McLeod was not politically active and voted Tory. Gladstone had been Fullerian Professor of Chemistry at the Royal Institution but retired early. Independently wealthy, he conducted some physical chemistry research privately. He is mentioned many times in McLeod's diary, as are his many daughters. (Gladstone had six daughters and one son. One of his daughters married the politician Ramsay Macdonald.).

Diary, 13 December 1885. Ramsay moved to the chair of chemistry at University College London on the retirement of A. W. Williamson in 1887. The Savile Club was a favourite meeting place for privileged scientists in this period. Membership was exclusive and expensive. In 1899 when his children's education bills were mounting McLeod could no longer afford membership and resigned.

Unwin William Cawthorne , FRS (1838–1933) was a close friend. Unwin had been a professor at the Royal Indian Engineering College before moving to the chair of engineering at the City and Guilds' Central Technical College in South Kensington in 1884. William James Russell, FRS (1830–1909) studied chemistry under Thomas Graham at University College and, in the late 1880s, was lecturer in chemistry at St. Mary's Hospital Medical School. Like McLeod he was active in many societies. He was a founder of the Institute of Chemistry, and was elected President of the Chemical Society in 1889.

Diary, 30 November 1893. For the final paper in a series by Scott on the atomic weights of hydrogen and oxygen see Scott A. , “On the composition of water by volume”, Philosophical transactions of the Royal Society, clxxxiv (1893), 543–68. Alexander Scott had studied chemistry with Alexander Crum Brown and James Dewar in Edinburgh. Later he was Dewar's demonstrator in Cambridge and the two of them carried out some atomic weight measurements there. Scott was an active member of the Chemical Society and became President in 1915. Another of his interests was archaeology. After losing his job as superintendent at the Davy-Faraday laboratory in 1910 he worked privately, including as a consultant to archaeologists, until being appointed director of the British Museum laboratory in 1919. Scott is mentioned often in McLeod's diary and, because of Scott, McLeod was to pay close attention to reports of Howard Carter's archaeological work in Egypt. Mond, a major chemical manufacturer, funded the Davy-Faraday Laboratory with the intention that scientists working there be provided with up-to-date facilities and technical assistance, but no salary. As superintendent, Scott was an exception and was paid £400 a year but his relationship with Dewar, the laboratory's director, deteriorated and he was to blame Dewar for the termination of the superintendent position. The row and subsequent legal tussle over the termination are mentioned in later entries in McLeod's diary. For details of Scott's atomic weight work see Robertson Robert , “Alexander Scott (1853–1947)”, Obituary notices of Fellows of the Royal Society, vi (1948), 1948–62. For Scott's work at the Royal Institution and his dismissal, see Watson Katherine D. , “‘Temporary hotel accommodation’? The early history of the Davy-Faraday Research Laboratory, 1894–1923”, in James, op. cit. (ref. 18), chap. 9. For Ludwig Mond (1839–1909) see Greenaway Frank , “Mond family (per. 1867–1973), chemical manufacturers and industrialists”, Oxford dictionary of national biography (Oxford, 2004). It is difficult to sort out the many people named Scott mentioned in McLeod's diary, but four in particular stand out. In addition to A. Scott, McLeod was on close terms with the eminent palaeo-botanist Dunkinfield Henry Scott, FRS (1854–1934), Jodrell Professor at University College, and his wife, Henderina Scott, who had interests in geology and cinematography. McLeod met Scott, son of the architect Sir George Gilbert Scott, when Scott was assistant professor of botany at the Royal School of Mines (where Henderina was a student). Many years later the families were near neighbours in Richmond. Active in the British Association, Scott and McLeod were the Association's official auditors in the 1880s and '90s. Robert Henry Scott, FRS (1833–1916), Director of the Meteorological Office, is another often mentioned. McLeod was responsible to him for measurements taken at Cooper's Hill and took on some extra tasks such as, in 1898, testing a series of thermometers in the snow.

Diary, 19 January 1888. Later, when William Huggins gave an address at the British Association meeting in Cardiff on stellar and solar spectroscopy without mentioning Lockyer's name, McLeod was similarly annoyed (diary, 19 August 1891).

Diary, 1 April 1897.

Diary, 15 March 1888. There was much interest in the evolutionary history of mammals and how to place the monotremes. Their embryological/developmental stages were widely studied at this time. Edward Bagnall Poulton (1856–1943) was appointed Hope Professor of Zoology at Oxford in 1893. In the 1880s he was a tutor at Keble College and McLeod met him there. There are several references to Poulton in McLeod's diary. For more on the Keble connection see below.

Ward Harry Marshall , FRS (1854–1906) was an eminent mycologist who had been educated at the Normal School of Science under T. H. Huxley. He worked on fungal disease in coffee plantations in Ceylon, and was briefly a lecturer at Owens College before his professorial appointment at the Royal Indian Engineering College. McLeod recorded attending Ward's Croonian Lecture, “The relation between host and parasite in certain epidemic diseases of plants” (diary, 27 February 1890), later published in Proceedings of the Royal Society, xlvii (1889–1890), 213–16. For work on plants under reduced pressure and different temperatures see diary, 20 March — 1 April 1891, and for the dinner party with nursery rhymes see diary, 27 May 1892. For work on the action of light on bacteria and on fungal spores there are several diary entries in the early 1890s and several papers in Proceedings of the Royal Society in the same period; lecture at Royal Institution (diary, 27 April 1894). In 1897 McLeod visited Ward in Cambridge and looked around his new laboratory. The Wards gave a dinner party at which McLeod met Ida Freund, lecturer in chemistry at Newnham (diary, 24–25 April 1897). Henry Edward Armstrong, FRS was professor of chemistry at the City and Guilds Central Technical College. See Rodd E. H. , rev. Brock W. H. , “Armstrong, Henry Edward (1848–1937), chemist and educational reformer”, Oxford dictionary of national biography (Oxford, 2004).

Diary, 20 March 1890. Arthur Schuster, FRS (1851–1934) was professor of applied mathematics at Owens College, Manchester. Bakerian Lecture: “The discharge of electricity through gases; (preliminary communication)”, Proceedings of the Royal Society, xlvii (1889–90), 526–61. Wyndham Rowland Dunstan, FRS (1861–1949) was a lecturer in chemistry at St. Thomas's Hospital Medical School. He became director of the scientific and technical department of the Imperial Institute in 1896.

Diary, 29 April 1891. Lieutenant General Richard Strachey, FRS (1817–1908) joined the Meteorological Office after a distinguished military/scientific career in India where, among other things, he founded a meteorological service. George Mathews Whipple (1842–1893) was superintendent at the Kew Observatory and was a specialist in wind pressure and velocity. McLeod mentions both men often and had many dealings with them in relation to calculating machines and meteorological instruments.

Diary, 23 May 1889, 17 February 1893. After Virchow's talk, McLeod, together with H. E. Armstrong and Frank Clowes (1848–1923), professor of chemistry at University College, Nottingham, went to a Chemical Club dinner and then to hear T. K. Rose, assistant assayer at the Royal Mint, give a paper at the Chemical Society on gold assaying. McLeod had known Clowes when he was a student at the Royal School of Mines.

Ladysmith had been relieved on 28 February 1900 after a long siege, and the British army was expected to relieve Mafeking (now Mafikeng) at any moment (they did, on 17 March). London's streets were very crowded during much of March. On 8 March, the day of the Bakerian, Queen Victoria was to make a public appearance. After dinner Tilden and McLeod went to the Chemical Society to hear a number of papers. Sir Augustus William Tilden (1842–1926) was then professor of chemistry at the Royal College of Science. He became president of the Chemical Society in 1903.

Diary, 31 January, 23 February, 25 April 1895. For the Royal Society paper see ref. 17. Rayleigh and Ramsay made a preliminary announcement of their discovery at the Oxford British Association meeting in 1894. At that meeting McLeod noted that Rayleigh told him that Ramsay had found yet “another gas from the air” (diary, 13 August 1894; I think he meant helium). (McLeod and Rayleigh also had a private discussion on the new gases at the British Association meeting in Ipswich in the following year.) There was criticism of the new findings, both at Oxford and at the Royal Society. Like Dewar some others believed that argon was simply an allotropic form of nitrogen (see also ref. 122 below for work on nitrogen allotropes by J. J. Thomson). Interestingly McLeod was working on the allotropes of arsenic (another group 5a element) in the same period. He delivered a paper on the topic at the same Oxford British Association meeting and published a summary. See McLeod Herbert , “On Schuller's yellow modification of arsenic”, Chemical news, 21 September 1894, 139. For more on the counter arguments to argon see Brock William H. , The Fontana history of chemistry (London, 1992), 331–7. Rayleigh's weighing apparatus was later displayed at the Royal Institution. See below for McLeod's giving Rayleigh assistance.

Ramsay William , “On a gas showing the spectrum of helium, the reputed cause of D₃, one of the lines of the coronal spectrum”, Proceedings of the Royal Society, lviii (1894–95), 65–67. Crookes William , FRS had been working on the spectroscopic identification of lanthanide (rare earth) and group 3b metals since the 1870s and was an obvious person to ask for help in the spectroscopic identification of argon and helium. Brock W. H. , “Crookes, Sir William (1832–1919)”, Oxford dictionary of national biography (Oxford, 2004).

Diary, 4 February 1897. McLeod was a supporter of Ramsay; Perkin was to win the Longstaff medal three years later. Augustus George Vernon Harcourt, FRS (1834–1919) was reader in chemistry, and fellow of Christ Church, Oxford.

In 1888 McLeod and Edward Frankland corresponded on who should be nominated for the Royal Society Council. They agreed on Armstrong but McLeod wanted Vernon Harcourt and Frankland wanted James Bell. (Bell headed the laboratory at the Society of Public Analysts and was a specialist in the adulteration of food products. The laboratory was later taken over by the government and upgraded under the direction of T. E. Thorpe.) As it happened, the second chemist to be nominated for the Royal Society Council in 1888 was Henry Roscoe.

Diary, 4 April 1889. Armstrong's politicking activities can be seen also in his correspondence held in the Imperial College London Archives. Arthur Nevil Rücker (1848–1915) was then professor of physics at the Royal College of Science. He did much work on electromagnetism in collaboration with A. W. Reinold. Arnold William Reinold, FRS (1843–1921), educated at Oxford under R. B. Clifton, was professor of physics at the Royal Naval College at Greenwich. Both men are mentioned often in McLeod's diary. Bakerian Lecture: Rucker A. W. Thorpe T. E. , “A magnetic survey of the British Isles”. This work followed earlier studies by Edward Sabine and others.

Brown Horace Tabberer , FRS (1848–1925), a former student of Frankland's at the Royal College of Chemistry, worked in the brewing industry until the 1890s after which he carried out research on fermentation at the Royal Botanical Gardens at Kew.

Clarke George Sydenham (1848–1933), later Lord Sydenham, was an army engineer who taught geometry and engineering drawing at Cooper's Hill before being sent overseas as a colonial administrator. He returned in the 1890s to become head of the gun-carriage department at Woolwich where McLeod visited him and, on occasion, gave advice — For example, on the training of a gun by electric motor (diary, 23 May 1895). After further government service related to Imperial defence, Clarke was appointed Governor of Victoria (Australia) in 1901 and Governor of Bombay in 1907. His wife and daughter both died in Bombay and McLeod recorded receiving grieving letters. At Cooper's Hill the two men had collaborated on various technical projects and published some joint papers. In later years they grew apart as Clarke became increasingly reactionary. After the First World War he supported the eugenics movement of which McLeod disapproved, and blamed the ‘decline’ of empire on, among others, socialists, pacifists, suffragettes, and Jews. He was to become a prominent anti-Semite. He also headed the British Science Guild, 1917–20. For Lodge and Unwin see, for example, diary, 13 and 15 December 1885. McLeod also helped to collect signatures for the chemists Victor Veley and William Perkin Jr (see, for example, diary entries in February 1890). Aside from in the year after his own election when he described the balloting at the Royal Society in detail, McLeod makes only brief mention of it in his diary. He noted some debate over procedure during the election of foreign members in 1888, the year in which Henri Becquerel was admitted.

Diary, 6 May 1891 and 28 April 1896. At that time Robert Bellamy Clifton (1836–1921) was head of the Clarendon Laboratory at Oxford; Oliver Joseph Lodge (1851–1940) was professor of physics and electrotechnics at Liverpool; Joseph John Thomson (1856–1940) was Cavendish Professor at Cambridge; William Henry Mahoney Christie (1845–1922) was Astronomer Royal; and William Grylls Adams (1836–1915), brother of John Couch Adams, was professor of natural philosophy at King's College London.

Diary, 15 June 1892. Crookes demonstrated a flame arising from a high voltage a.c. arc in air and claimed that it was due to the oxidation of nitrogen. At an earlier soirée, 9 June 1886, McLeod heard a performance of the Mikado over the phone, “very metallic”. At a soirée, 8 June 1898, McLeod reported that Ramsay showed off the spectrum of krypton. On the following day Ramsay read a paper on the new gas, but it was not accepted for publication by the Royal Society since it had been read earlier at the French Academy. A soirée held on 19 June 1889 attracted a large crowd to see E. J. Muybridge's photographs of animals in motion.

Going for “beer and buns” with other scientists is something McLeod often recorded. One interesting example was after a law case in which a chemical analyst, William Johnstone, sued the president of the Chemical Society, A. W. Tilden, for wrongfully being thrown out from both the Society and the Institute of Chemistry. It was the latter that Johnstone cared about since it was the body that accredited professional chemists and analysts. The case was settled when Johnstone agreed not to use the letters FIC after his name, but both sides had to cover their costs. After the court settlement McLeod, who had been called as a witness, joined Tilden and other Society members, Howard D. Groves C. Thorpe T. E. Page F. W. Ramsay W. Dyer B. S. (an eminent professional analyst and also a witness) for “beer and buns”. See diary 31 May 1892.

Diary, 23 May 1885. Frederick Guthrie, FRS (1833–86) was educated as a chemist but then turned to practical physics. He was professor of physics at the Normal School of Science and founder of the Physical Society. One year after this meeting, the day after Guthrie's death from complications during surgery, McLeod received a letter from Mrs Guthrie complaining that the doctors would not tell her what had been wrong with her husband. The Physical Society raised money for her since she was left poorly off. Shelford Bidwell, FRS (1848–1909) was a barrister who taught himself physics and carried out work in South Kensington, mainly on the photoelectric properties of selenium. For many physicists the South Kensington laboratories and the Physical Society provided a popular alternative locus to Cambridge, home of the mathematical physicists. It was also a more comfortable place than the Royal Society for showing new apparatus and presenting sketchy hypotheses. Schoolteachers and women scientists were admitted as members.

Rodwell G. F. was a science teacher at Marlborough School where C. V. Boys had been one of his students. Charles Vernon Boys, FRS (1855–1944) studied physics under Guthrie and was assistant professor of physics at the Royal College of Science. His technical skills were widely admired and are discussed in the fine obituary by Lord Rayleigh ( Strutt R. J. ); see Obituary notices of Fellows of the Royal Society, iv (1944), 1944–88. One of the things Rayleigh mentions was that Boys, who was on the Royal Society soirée committee for many years, was largely responsible for there always being so many interesting things on display. For Abney, see ref. 124 below.

Many novel electrical inventions were on display. The Waltham company was one of several American companies (Singer Sewing Machines was another) which impressed people with their machine tooling and their ability to mass produce.

Ayrton William Edward , FRS (1847–1908) was professor of physics at the City and Guilds Central Technical College. For more on Ayrton and electrical measuring devices see Gooday Graeme J. N. , “The morals of energy metering: Constructing and deconstructing the precision of the Victorian electrical engineer's ammeter and voltmeter”, in Wise M. Norton (ed.), The values of precision (Princeton, 1995), chap. 10.

Diary, 26 February 1898.

Diary, 8–10 May 1885. Ayrton Hertha (1854–1923) was a scientist in her own right and was then working on the electric arc. Henry Selby Hele-Shaw, FRS (1854–1941) had been an outstanding student at Bristol. He was appointed lecturer on graduating and, in 1881, professor of engineering. In 1885 he moved to become professor of engineering at University College Liverpool. In Bristol he was working on the measurement of wind velocity and direction, on automatic anemometers, bicycle speedometers, and other such devices. He was interested more generally in mechanical integration and shared an interest in calculating machines with McLeod.

Thompson Silvanus Phillips , FRS (1851–1916), who had earlier taught at University College Bristol, was professor of physics and Principal of Finsbury Technical College. McLeod had known him for many years. George Francis Fitzgerald, FRS (1851–1901) was professor of physics at Trinity College Dublin and was known to McLeod as a frequent visitor to the Royal Indian Engineering College (see ref. 113) and also through his work as an examiner (see below). Fitzgerald displayed his own model of the ether at the Inventions Exhibition.

Forbes George (1849–1936), son of the physicist Forbes J. D. , was professor of natural philosophy at Anderson's Institute before coming to London in 1880 where he worked on electricity generation.

Edmondson Joseph , a major manufacturer of calculating machines whose main workshop and factory was in Halifax, was someone with whom McLeod often corresponded. See “Summary of lecture on calculating machines” (full paper delivered 28 March 1885), Proceedings of the Physical Society of London, vii (1885), 1885–85. In the late nineteenth century the Physical Society held several sessions devoted to calculating machines of various kinds. For example on 13 April 1894 machines based on some ideas of Olaus Henrici, professor of mathematics at the City and Guilds Central Technical College in South Kensington, were discussed.

Major General Henry Prevost Babbage (1824–1918) was the youngest son of Charles Babbage and inheritor of the calculating engine dream. He defended the idea of digital computation well before any such machines existed.

Diary, 27–28 March 1885. All four dinner companions had been colleagues at Cooper's Hill where Gregory was a demonstrator in physics. The mathematician Sir Alfred George Greenhill, FRS (1847–1927) returned to Cambridge, and to a chair, after just a few years at the college. In 1876 he was appointed professor of mathematics at the Royal Artillery College in Woolwich. He was a second wrangler and a much honoured mathematician.

Diary, 14 May 1885. Frederick John Jervis-Smith (1848–1911) read classics at Oxford, was a self-taught physicist and an excellent inventor of electrical instruments. The Millard Laboratory at Oxford, where he became lecturer in 1888, was largely equipped at his expense. See Simcock Tony , “Mechanical physicists, the Millard Laboratory, and the transition from physics to engineering”, in Fox Robert Gooday Graeme (eds), Physics in Oxford 1839–1939: Laboratories, learning and college life (Oxford, 2005), chap. 5. For an illustration of a later version of Smith's dynamometer (ergometer) see p. 202. Smith is mentioned often in McLeod's diary (see also below).

Odling William , FRS (1824–1921) was Waynflete professor of chemistry at Oxford but had strong ties to London where he grew up. He was educated at the Royal College of Chemistry and had been lecturer in chemistry at Guy's Hospital before moving to Oxford. Sir William Henry Perkin, FRS (1838–1907), another former student of A. W. Hofmann at the Royal College of Chemistry, discovered the first aniline dye (mauve), was a chemical manufacturer and carried out private research. Sir Henry Enfield Roscoe, FRS (1833–1915) was then professor of chemistry at Owens College, Manchester. Walter Weldon, FRS (1832–85) was the inventor of a number of chemical processes, especially in relation to bleaching (at Weldon Chlorine Processes, Lincoln's Inn Fields) and was famed also for his ballads performed at dinners of the Society for Chemical Industry. McLeod had known them all for many years. On the other jury one of McLeod's colleagues was the physicist C. V. Boys.

For example, see diary, 28 May 1885. The Brin process for making oxygen was especially admired, as were the dye chemicals displayed by Badische Anilin und Soda Fabrik (BASF).

These three remained lifelong friends and each was asked to be godfather to one of McLeod's children. In the late 1880s David Howard (1839–1916) was managing his family's chemical company, Howards & Sons in Essex. He was a co-founder of both the Institute of Chemistry and the Society for Chemical Industry and served terms as president of both institutions. Alexander Gillman (1843–1903) was a brewery chemist who, in 1886, started the successful brewing consultancy firm of Gillman & Spencer with another Royal College of Chemistry graduate, Ernest Spencer. The firm (maltings experts) is still in existence. As young men the four friends shared deeply felt religious views, especially as they related to science. They were collaborators on the Scientists' Declaration. For Groves see ref. 27. For the Scientists' Declaration, see Brock W. H. MacLeod R. M. , “The Scientists' Declaration: Reflexions on science and belief in the wake of Essays and reviews, 1864–5”, The British journal for the history of science, ix (1976), 39–66; also Gay, op. cit. (ref. 2, 2007).

Diary, 26 March 1886. Cameron was also the public analyst for large areas of Ireland and professor of chemistry at the Royal College of Surgeons of Ireland. Francis Robert Japp, FRS (1848–1926) was a lecturer at the Normal School of Science, but moved to a chair in Aberdeen in 1890. Percy Faraday Frankland, FRS (1858–1946) was another old friend whom McLeod had known since working for his father, Edward Frankland. P. F. Frankland was professor of chemistry at Mason College, Birmingham (see also below).

The Chemical Society then had the rooms now occupied by the Geological Society, in Burlington House, which fronted Piccadilly. In the evening McLeod, his family, and some of his Cooper's Hill colleagues watched the celebrations in Windsor. The castle was illuminated and the bridge to Eton had a ceremonial arch at each end (the one at the Eton end was decorated with guns, pistols, ramrods and swords). There were fireworks for several nights in a row. Ten years later on the Queen's sixtieth anniversary five scientists were given jubilee knighthoods: Crookes W. Lockyer J. N. Huggins W. Frankland E. Strachey R. , Frankland died in the following year (1898) and McLeod attended the funeral in Reigate. The service was conducted by T. G. Bonney, professor of geology at University College, assistant general secretary of the British Association, and an ordained Anglican priest. Lord Lister and Michael Foster represented the Royal Society and many chemists were present.

Sir Thomas Stevenson, MD (1838–1908) was a forensic specialist and Senior Analyst at the Home Office. For his earlier career see ref. 120.

Diary, 28 March 1889 and 26 February 1891. Lord (Lyon) Playfair (1818–98) was by then long retired from the chair of chemistry in Edinburgh (where both Dewar and Guthrie had been his assistants) and had retired also from his political career. He was president of the British Association in the 1880s. Lord Salisbury was Prime Minister in 1891. Another major Chemical Society dinner was held in honour of six past presidents who had been members of the society for fifty years (Gilbert, Frankland, Odling, Abel, Williamson and Gladstone); Whitehall Rooms, 11 November 1898.

Diary, 5 May 1893. Hofmann died in April 1892 aged 74. Sir Frederick Abel, FRS (1827–1902), an expert on explosives, was Chemist for the War Department, working at Woolwich Arsenal until his retirement in 1888. Like Perkin, Abel was one of Hofmann's first students in London.

Diary, 28 May 1896. William Chandler Roberts-Austen (1843–1902) was a student and later professor of metallurgy at the Royal School of Mines, before becoming Master of the Mint. It would appear that Roberts-Austen hosted at least one large reception at the Mint each year, usually with technical things on display. For example, on 4 May 1899 a reception was held for the Iron and Steel Institute when a novel electrical furnace was on show.

Diary, 19 December 1895.

See diary, 13–18 August 1885 for correspondence with Lord Salisbury on improving the connection, and lowering the cost of telegraphy to and from the Ben Nevis Observatory. McLeod was helping Salisbury with the electrification of Hatfield House at the time. In December 1885, after looking over the generating equipment, he asked his friend Unwin for help with the water turbines (diary, 19–22 December 1885; see also Gay , op. cit. (ref. 2, 2003)). For meeting in Aberdeen see diary, 25 August — 7 September 1885. Harold Baily Dixon, FRS (1852–1930) had been a student of Harcourt at Oxford where he continued to work until becoming professor of chemistry at Owens College, Manchester, in 1886. As to holidays, after the 1888 British Association meeting in Bath, McLeod and his wife took a more gentle holiday in Devon where they met the Ramsays. Diary, 11 September 1888.

McLeod had a long interest in electrical timekeeping. For the British Association meeting, see diary, 8–16 September. Red Lion dinners were a regular feature at British Association meetings but a more select Red Lion Club existed in London. McLeod sometimes dined there as a guest. For the Red Lions see Gay Gay , op. cit. (ref. 27).

Albright Arthur (1811–1900) co-founded the chemical manufacturing firm of Albright & Wilson in 1856 with Wilson J. W. (1834–1907). At first the company produced mainly phosphorus and chemicals for the match industry but later diversified. McLeod met the Wilson family while in Birmingham. McLeod noted that Henry Armstrong was also staying with the Albrights and that Armstrong enjoyed playing tennis in the garden with Albright's granddaughters. For the British Association meeting see diary entries, 1–10 September 1886.

Retroactively the earthquake is said to have measured 7.3 on the Richter scale and is the largest ever recorded in the southeastern USA; about 60 people were killed.

Diary, 1–6 September 1886.

Diary, 1 September 1887. In this period Edward (Henry) Schunck (1820–1903) read many papers at the Royal Society on the chemistry of chlorophyll and its role in plants. He was a Manchester industrialist and specialist in dye chemistry.

Diary, 12 September 1899. John Abbot & Co. was a large engineering and manufacturing company that made a range of products including railway locomotives. Lord (William George) Armstrong (1810–1900), who profited from all that ‘dirt’, was a major industrialist and armaments manufacturer. Much of Jesmond Dene, a steep sided valley of the Ouse near Newcastle, was owned by Armstrong. He built a house and banqueting hall there and commissioned the design of parkland, now public. By the late nineteenth century Armstrong was no longer living at Jesmond Dene but in a yet grander residence, Cragside, in Rothbury, Northumberland, also surrounded by magnificent gardens; today it belongs to the National Trust.

Diary, 2 September 1890. Today the discovery is credited to both Priestley and C. W. Scheele working independently in 1773–4. Lavoisier is credited with recognizing that oxygen was an element about two years later.

Diary, 8 September 1890.

The Kempes were relatives of Sir Alfred Kempe, later Treasurer of the Royal Society. For party see diary, 5 August 1892. For Kipping see ref. 103 below. Mrs Kipping's two sisters were married to Arthur Lapworth (see ref. 99) and W. H. Perkin Jr. Wilhelm Ostwald (1853–1932) was professor of chemistry at Leipzig, a founder of classical physical chemistry, and winner of the Nobel Prize for chemistry in 1909 for his work on catalysis and chemical kinetics.

Diary, 13–21 September 1899.

For Toronto meeting and voyage see diary, 5 August — 8 September 1897.

Brauner Bohuslav (1855–1935) was a friend of D. I. Mendeleev and, like Crookes, carried out work on the chemistry of the actinides and lanthanides. He gave a paper in Toronto on the atomic weight of thorium. He had long been a proponent of atomic weight determinations being based on oxygen (rather than hydrogen) and carried out several in that way. His view won out and oxygen became the standard until replaced by carbon 12. In the 1880s Brauner predicted the existence of what were later known as isotopes. His speculation was not unlike that of Richards (see Gay , op. cit. (ref. 21)). McLeod enjoyed Brauner's company and noted that he was a very amusing man.

Meldola Raphael , FRS (1849–1915) and Silvanus Phillips Thompson were friends and colleagues at Finsbury Technical College where Meldola was professor of chemistry. Sir (James) Alfred Ewing, FRS (1855–1936) was professor of engineering at Dundee until 1890 when he moved to Cambridge.

Lord (Joseph) Lister (1827–1912), renowned for his contributions to antiseptic surgery, was President of the Royal Society. Sir John Evans (1828–1908), Treasurer of the Royal Society, was a paper manufacturer with interests in archaeology and numismatics. He was the father of the archaeologist Sir Arthur Evans. McLeod had many dealings with him in connection with the Royal Society Catalogue of Scientific Papers. Lister, Evans and Kelvin were awarded honorary degrees by the University of Toronto during this visit. It was usual for universities in towns hosting the British Association to award honorary degrees to senior office holders in the Royal Society and British Association.

Interestingly not everyone wanted to see the falls, a ‘must-see’ for many of today's tourists. John Perry, FRS (1850–1920) was professor of mathematics and mechanical engineering at Finsbury Technical College from 1882 until 1896 when he moved to the Royal College of Science. His main interests were in electrical science and he worked together with William Ayrton on a number of projects. In 1885 McLeod wrote about a party at Perry's (Perry was then a neighbour of Lockyer on Pennywern Road, Earls Court) where a model of Fleeming Jenkin's telpherage line was on display. Perry and Eustace Balfour tried to persuade McLeod to join in a related business venture but he declined. For party at Perry's see diary, 13 February 1885.

In the 1880s some direct current was generated and delivered within a radius of about one mile, but only for electrical lighting. It was Thomas Evershed, and then George Westinghouse, who made the first plans for major electricity generation at Niagara. Unwin had joined the Niagara Commission in 1890 and helped to design the flumes. For more on Unwin and hydro-electric power, see Walker E. G. , William Cawthorne Unwin (London, 1938).

For Veley's visit to Cooper's Hill, see diary entries for April 1889. Quotation, 7 June 1889. Victor Herbert Veley, FRS (1856–1933) was an Oxford educated chemist who made his career at Oxford before moving to London in 1908 to engage in various business ventures.

Talbot Edward Stuart (1844–1934) and Lavinia Talbot (1849–1939) were also promoters of women's education at Oxford and active in the foundation of Lady Margaret Hall. Both followed in the footsteps of their fathers who had been keen supporters of the Oxford Movement. The university was divided on the new (Keble) college. Many people viewed it with contempt, perhaps fearing that it would spur further defections to the Catholic church (Talbot's uncle had become a Roman Catholic priest). It helped that a young aristocratic couple was placed in charge at Keble and that the University Test Act had been passed in 1871. Lavinia was the daughter of the fourth Baron Lyttelton and was related to both the Spencer and Cavendish families. Catherine Gladstone was her aunt. W. E. Gladstone and various aristocrats, including Lord Salisbury and members of the Cecil and Balfour families, were frequent visitors at Keble. Such visits helped the college to become more widely accepted. McLeod began a correspondence with Edward Talbot in the 1870s, was first invited to visit Keble College in 1877 and was a regular visitor thereafter. He deeply admired the Talbots, was guided by them in religious matters and remained on friendly terms all his life. The Talbots left Oxford when Edward became Vicar of Leeds in 1888. McLeod records visiting them during there during the British Association meeting in 1890. He also noted that his friend W. A. Shenstone (chemistry teacher at Clifton College) was staying with the Talbots. McLeod continued to visit the Talbots after Edward became successively Bishop of Rochester, Southwark and Winchester. He attended their children's weddings and was present at a number of other family occasions. The Talbots also visited the Royal Indian Engineering College and Edward gave sermons in the chapel when there. McLeod also received invitations to the various homes of the Gladstones. W. E. Gladstone was a Tory when young; however, when it came to extending friendship, religious outlook meant more to the Talbot, Lyttelton, Gladstone clan, and to the Cecil, Balfour, Rayleigh clan, than did political affiliation. For more on the former family group see Fletcher Sheila , Victorian girls: Lord Lyttelton's daughters (London, 2001). The two groups were socially connected in many ways. For example, Lavinia Talbot's brother, Spencer Lyttelton, was Gladstone's private secretary during his first premiership. Among Spencer's closest friends were John Strutt (later third Baron Rayleigh) and Arthur Balfour. McLeod, close in age, met these men socially already during the 1870s. Balfour and his sister, who later married Strutt, were also devotees of the Talbots; Balfour and McLeod met in several places including occasionally at Keble. For more on some of the scientific and religious ideas current at Keble see Talbot E. S. , Memories of early life (London, 1924), chap. 3; Richard England, “Natural selection, teleology and the logos: From Darwin to the Oxford Neo-Darwinists, 1859–1909”, in Brooke Osler and van der Meer (eds), op. cit. (ref. 14), 270–87. For a discussion of anti-naturalism and the views of Arthur Balfour see Lightman, op. cit. (ref. 14), 343–66.

Diary, March 7 1885. Cecil E. A. Robert Bob , then a student at Oxford, was the third son of Lord Salisbury. Another dinner guest was Henry Liddon, canon of St Paul's. Liddon, an eminent clergyman and author of the Life of Edward Bouverie Pusey (4 vols, London, 1894) had earlier declined to become the first warden of Keble. He was famous for his sermons and people queued to hear him. McLeod was among his many admirers and noted how “very amusing” he was. For the earlier work with Burdon-Sanderson at Cooper's Hill see Gay , op. cit. (ref. 2, 2003).

Diary, 22 June 1889.

Fisher Walter William (1842–1920) was a tutor at Balliol and chemistry demonstrator for the university. McLeod enjoyed being shown the collection of falcons and owls kept by Odling's son.

McLeod first met Clifton in 1870. For Smith see ref. 61. Conroy John Sir , FRS (1845–1900) worked also in the Millard Laboratory, on optics. McLeod was interested in him as much for his connection to Keble College as for his scientific research. Both were admirers of Lux mundi, an 1889 collection of essays by Oxford theologians (including Talbot) defending both an Anglo-Catholic moral philosophy and the need for the Church to accept aspects of modern thought and new Biblical criticism. On his death Conroy left Keble a substantial sum for science. Chemist, David Henry Nagel, was a demonstrator under Conroy, later a university demonstrator in physical chemistry.

For example, see diary, 23 November 1889 and 7 June 1890. Harcourt was using some gas analysis apparatus built by McLeod. Glassblowing skills were still rare outside London and a few other glassmaking centres.

Diary, 26 November 1889.

Twenty-seven men took the practical exam in 1889 and thirty-four in 1890. McLeod recorded examining just two women from Somerville in 1889, and one or two (the diary is unclear) in 1890. The women passed their exams as did most of the men.

The principal physics examiners in this period were Oliver Lodge and G. F. Fitzgerald. McLeod records having lunch with them on several occasions during examination periods.

McLeod almost had a falling out with Armstrong over the DSc examination of Armstrong's former student, Arthur Lapworth, FRS (1872–1941). McLeod and the other examiners were at first reluctant to pass him. McLeod wrote “he is a sharp fellow but careless” (diary, 18 June 1895). Lapworth, a future eminent professor at Manchester, was awarded the DSc in 1895.

Diary, 3 August 1893. McLeod often stayed with the Armstrongs, and not just for examination work. He made some interesting comments on the ways in which Armstrong taught his own children, not only chemistry but science more generally. There was a home laboratory and the children kept a large menagerie of guinea pigs, pigeons and other small animals in cages in the garden. Imperial College London Archives (Henry Armstrong papers) has a notebook containing essays by three of Armstrong's children, Harry, Edward and Edith, with interesting details of historical and natural history outings they made. The essays are illustrated with photographs and newspaper cuttings. For Armstrong's pedagogical approach more generally, see Brock W. H. , H. E. Armstrong and the teaching of science (Cambridge, 1973) which includes mention of the children's education and essays. McLeod also records staying with Dunstan at Camden Hill in North London for marking sessions and that he, too, had “very nice” children (diary, 2 August 1894).

Diary, 21 December 1892, 23 August 1894, 20 February 1896. See also Ramsay W. , letter to the editor, Chemical news, 10 August 1894, 72. This was not the end of it since even after joining the examining board, Ramsay publicly criticized Dunstan's questions. Despite all of this McLeod and Ramsay appear to have had a fairly close friendship. Like many friendships made when young, theirs picked up again as they grew older. After Ramsay was diagnosed with cancer of the jaw, in November 1915, McLeod stayed in touch with Lady Ramsay when Ramsay was too ill to receive visitors. Ramsay underwent two operations, radium and X-ray treatment; but there was little the doctors could do and he died in July 1916.

Diary entries in 1897–8, especially July 1897.

Frederick Stanley Kipping (1863–1949) was a lecturer at the City and Guilds Central Technical College, later professor in Nottingham. Kipping wrote to McLeod at least three times asking for help in getting the examiner's job. McLeod also had letters from four other people that year asking the same. In 1898 Kipping was appointed to succeed P. Frankland as assistant examiner at the Pharmaceutical Society.

McLeod noted that in 1898 only 104 out of 340 passed the final exams at the Pharmaceutical Society. Diary, 21 July 1898. In the October examination of that year only 66 out of 260 passed.

Diary, 29 May 1901.

Poynting was professor of physics at the University of Birmingham. He and Thomson were close friends from their days as demonstrators at Owens College and continued working together for much of their lives. McLeod had earlier helped Thomson with some of his experiments (see below).

In the 1890s it seems that many people, including McLeod, began riding bicycles. This resulted in new forms of socializing, allowing for visits slightly farther afield for those who earlier could not easily afford horse-drawn transport. T. E. Thorpe broke his leg by falling off his bicycle in April 1896.

Bishop Matilda Ellen (1842–1913) was headmistress of Oxford High School for Girls before her appointment at Royal Holloway. She resigned in 1897 when the Council decided to allow non-Anglican denominations to use the chapel for worship. Later she was appointed head of St. Gabriel's College, an Anglican college for training women teachers.

Harry Marshall Ward took an active interest in botanical instruction at Royal Holloway and helped Miss Corry, the first botany lecturer. Amelia (Min) McLeod acted as secretary for the continuing education classes which drew about 50–60 people each term (diary, 25 January 1889). For the planning of the chemistry laboratory see, for example, diary, 18 June 1887. For an example of McLeod's helping Miss Seward, and teaching her students how to blow glass, see 13 December 1888. Margaret Seward had been a student at Somerville and was the first woman to enter the honours mathematics school at Oxford (she obtained second-class standing in the degree examinations) and the first woman to receive first-class standing in the natural sciences (chemistry). She studied with Harcourt and was one of the women who took advantage of the short-term offer by Trinity College Dublin to receive its MA (degrees were denied to women by Oxford). She left Royal Holloway after her marriage and lived for several years in Singapore but was later appointed to a chemistry lectureship at King's College London. Eleanor Field was educated at Newnham College, Cambridge. For Seward see Pottle Mark , “McKillop (née Seward), Margaret (1864–1929)”, Oxford dictionary of national biography (Oxford, 2004).

This occurred on 16 December 1887 (the Queen's jubilee year) after which the picture gallery could be viewed at night. The pictures were a generous gift from Thomas Holloway, founder of the college, who had made a fortune from the sale of patent medicines. Another Thames Valley institution, Beaumont College, a Jesuit school in Old Windsor (known as the ‘Catholic Eton’), appears to have had good science laboratories and McLeod visited there too. This school closed in 1967 and the pupils moved to Stoneyhurst College in Lancashire.

Diary, 5 September 1891. McLeod had many conversations with Eustace Balfour who was chairman of a company that installed electrical lighting in the area around St. James's Square in London. See, for example, diary, 28 February 1889.

Philipp William Sir Schlich Daniel (1840–1925) worked for many years in the Indian Forest Service before being seconded to Cooper's Hill. McLeod also mentions helping the forestry specialist Percy Groom, later a professor at Imperial College, when he came to work at the college after a period in China. On the closure of the Royal Indian Engineering College much of the forestry work moved to Oxford. Robert Warington, FRS (1838–1907), son of a founder of the Chemical Society with the same name, was an eminent agricultural chemist who had worked with John Lawes at Rothamsted. He was briefly (1894–97) Sibthorpian professor of rural economy at Oxford. Warington and Sir Arthur Herbert Church, FRS (1834–1915) were both former students of the Royal College of Chemistry but Church went on to Oxford for a degree. Church, a close friend of McLeod, had wide interests and, aside from organic chemistry, worked in the areas of mineralogy and paint pigments. The latter led to his appointment as professor of chemistry at the Royal Academy of Arts. Church had some problems with the forestry students who claimed that he expected too much of them (diary, 4 December 1888). For more on Church see Kurzer Frederick , “Arthur Herbert Church, FRS and the Palace of Westminster frescoes”, Notes and records of the Royal Society, lx (2006), 139–59. Alfred Lodge (1854–1937), brother of Oliver Lodge, was professor of pure mathematics at the Royal Indian Engineering College until 1904. He then became a mathematics teacher at Charterhouse School. As a mathematician Lodge is best known for his many contributions to the construction of mathematical tables, hence his use of calculating machines. Lodge was a long-time member of the British Association mathematical tables committee, and its secretary 1888–96.

Minchin George M. , FRS (1845–1914) was professor of applied mechanics and taught both mathematics and some physics at the college. He was a friend of Alfred Lodge and of fellow Trinity College Dublin graduate, George F. Fitzgerald with whom he carried out some scientific work. Fitzgerald was a frequent visitor to the Royal Indian Engineering College. Minchin appears to have been very congenial, a good tennis player, and a good teacher. He moved to Oxford when the college closed. Minchin used his cells to measure the relative brightness of various stars and planets and gave a paper on this at the Royal Society on 30 January 1896 which McLeod attended. Minchin George , “The electrical measurement of starlight: Observations made at the observatory of Daramona House, Co. Westmeath in January, 1896”, Proceedings of the Royal Society, lx (1896–97), 42–52. First quotation, diary, 12 September 1891; second quotation, 9 January 1894. For McLeod's helping with some of Minchin's experiments see, for example, 15 September 1897.

Duncan Peter Martin , FRS (1824–91) was an apprentice surgeon who took the London MB before turning to natural history and geology. He was professor of geology at King's College London, a former president of the Geological Society and Wollaston medallist. He was ill for many months before his death. His funeral at Chiswick Church was well attended including by two other geologist friends of McLeod, Judd J. W. Seeley H. G. , Mrs Duncan was left in poor economic circumstances and McLeod led a successful effort for some financial support, albeit small, from the Royal Society Relief Fund (£25 in each of 1894 and 1895).

Diary, 13 June 1890.

See Gay , op. cit. (ref. 2, 2003). Sackville Cecil was Manager of the District Railway. The telephone exchange was at Mansion House. There are many entries on helping with the railway in the diary.

McLeod kept some good chronometers, a good binocular microscope, some drawing instruments and, for sentimental reasons, some submarine cable that Sackville Cecil had laid. The other instruments were sold. See, for example, diary, 28 April 1898. McLeod wrote Sackville Cecil's obituary; see Journal of the Physical Society of London, xvii (1899), 6–8. For more on electrical timekeeping, including brief mention of McLeod's and Sackville Cecil's interests in that area, see Gay Hannah , “Clock synchrony, time distribution and electrical timekeeping in Britain, 1880–1925”, Past and present, clxxxi (2003), 2003–40.

Guests included Armstrong H. E. Dyer W. Thiselton Herschel Alexander Groves C. Howard D. Thorpe T. E. Thorpe and McLeod became close friends late in their lives.

As mentioned above, McLeod's own sunshine recorder was a success but he also helped Whipple in a number of ways, for example in testing aneroid barometers and other meteorological instruments. He was to work also with Charles Chree, Whipple's successor as superintendent at Kew. McLeod records visiting several exhibitions of meteorological instruments held at the Institution of Civil Engineers. At one of these, in 1890, he met George James Symons, FRS (1834–1900) and chatted about black bulb thermometers. Symons worked at the Meteorological Office and was a specialist in rainfall distribution. McLeod visited Symons at his home at 62 Camden Square where a fine collection of instruments was in use in the garden, see diary, 18 March 1886, 20 March 1890 and 1 January 1891.

Water treatment had been a principal interest of E. Frankland under whom McLeod had worked earlier. In 1887 McLeod had to deal with some problems to do with sewage from the college's infirmary. He talked to many people about this including Sir Thomas Stevenson (1838–1908), a physician at Guy's Hospital and a specialist in water analysis and public health; and Francis De Chaumont, FRS, professor of hygiene at the Army Medical School. See, for example, diary, 19 May 1887.

The person at the India Office responsible for this was Sir Alexander Rendel (1829–1918), a civil engineer who had worked for many years in India. The laboratory was run consecutively by two analytical chemists: The first, Arnold Philip, was later Admiralty Chemist at Portsmouth; the second, Frank William Harbord (1860–1943), a former student at the Royal School of Mines, had worked with W. Roberts Austen at the Royal Mint before coming to Cooper's Hill. He became a private chemical consultant when the college closed, though McLeod tried hard to help him to another institutional position.

Diary, 7 May, 13–17 June 1886. Typically of McLeod he read much of the earlier literature on ozone, including J. Tyndall's account of its formation in the atmosphere. Ozone can be produced electrolytically from sulphuric or perchloric acid by using a small area anode and high area cathode so as to have a high anode current density. See McLeod Herbert , “On the electrolysis of aqueous sulphuric acid, with special reference to the forms of oxygen obtained”, Transactions of the Chemical Society, xlix (1886), 591–608. See also Thomson J. J. Threlfall R. , “Some experiments in the production of ozone”, Proceedings of the Royal Society, xl (1886), 1886–2. Thomson and Threlfall succeeded in making ozone by subjecting oxygen to a strong electrical field. Also of interest in light of future objections to Rayleigh and Ramsay's work is a paper by Thomson and Threlfall claiming that an allotrope of nitrogen was formed when an electrical discharge was passed through pure nitrogen. Thomson J. J. Threlfall R. , “On an effect produced by passage of an electric discharge through pure nitrogen”, ibid., 329–40. McLeod carried out a number of other electrolysis experiments in this period and corresponded and chatted with several people, notably Armstrong, about his results. See, for example, diary entries, October 1886. Armstrong and McLeod were both on the electrolysis committee of the British Association.

See diary, 26 May 1887 for the second chat with Thomson at the Savile Club. For comments on lecture and paper see diary, 28 May and 18 July 1887. Thomson J. J. , “On the dissociation of some gases by the electrical discharge”, Proceedings of the Royal Society, xlii (1887), 343–5.

When K. R. König gave a demonstration of his tuning forks (with English commentary by Thompson S. P. ) at the Physical Society on 16 May 1890, both Rayleigh and McLeod were present. König, a German, had been apprenticed with the violin maker J. B. Vuillaume in Paris and his tuning forks were said to be the best available. Rayleigh and McLeod also exchanged ideas with the colour vision specialist, Sir William De Wivesley Abney, FRS (1843–1920), a senior civil servant at the Board of Education. Abney carried out research also in spectroscopy (he produced one of the first infra-red spectra) and photography in a large laboratory in the South Kensington Museum. McLeod visited him often and took some of his students to be tested for colour vision (Abney's laboratory was the centre for testing the vision of sailors for the merchant marine).

Lady Rayleigh was away canvassing for her brother-in-law, Charles Strutt, Tory candidate for Saffron Walden in the upcoming general election (he lost).

For this visit see diary, 28–30 November 1885. McLeod and Rayleigh returned to London to attend the anniversary meeting of the Royal Society and McLeod noted sitting with Unwin, Tilden, Russell and Thorpe at the anniversary dinner.

Diary, 29–31 May 1886. McLeod records other visits at which he met Thomson and that William (later Sir William) Huggins and his wife were Rayleigh's guests on more than one occasion. McLeod mentions that psychologist and psychical researcher Edmund Gurney and his wife were guests at Terling on 4 June 1887 (Rayleigh was interested in the para-normal). McLeod had been a dinner guest at the Gurneys, in London in 1885. However, McLeod was a sceptic when it came to psychical matters.

In 1888–89 McLeod spent time in the Chemical Society library looking up various preparations of oxygen and made especial note of Döbereiner's 1832 method using KClO₃ and MnO₂. While the presence of MnO₂ allows for a lower decomposition temperature it contaminates the product. Dewar used this method when preparing his oxygen in 1896, but his liquid oxygen was turbid because of the presence of chlorine. Dewar discussed the problem with McLeod on 17 December 1896, the day on which he and Fleming gave a paper on the dielectric constant of liquid oxygen at the Royal Society. In the case of nitrogen, there were many exchanges between McLeod and Rayleigh in 1891–2. Rayleigh had not yet succeeded in preparing the pure gas chemically.

See diary entries, January—March 1890.

Rayleigh also had the help of instrument maker George Gordon who had worked with him earlier at the Cavendish Laboratory, and the help of family members including his son, Strutt R. J. , Despite continuing invitations, McLeod's visits to Terling declined in number during the 1890s because of family obligations.

Diary, 30 June and 9 July 1885. Simon Adams Beck opened the gas works in 1870 just west of Barking Creek and near the new docks. It soon became the largest gas and chemical works in Europe. The site was larger in area than the City of London. During the reclamation of the docklands in the late twentieth century the industrial waste gathered from the gas works was formed into an artificial hill, now parkland. Documents relating to the history of Beckton can be found in the archives of the London Borough of Newham.

For Snowdonia, diary, 13–20 April 1885. For Milnes, diary, 21 April 1898. Mrs Milne was Japanese. Milne John (1850–1913) was a former student at the Royal School of Mines.

The common existence of parallel research work and the emergence of singular discovery is a topic that was of much interest to the sociologist of science Merton Robert K. , See his The sociology of science: Theoretical and empirical investigations (Chicago, 1973), chaps. 15–17.

For more explicit treatment of McLeod's religious behaviour see Gay , opera cit. (ref. 2, 2000, 2003 and 2007).

My use of the term ‘gnostic’ is somewhat derivative of the way it was used by the political philosopher Eric Voegelin (1901–85).

The anticlericalism of the Risorgimento of Banti's period and of the later republican movement in Italy contributed greatly to Galileo's iconic status. He was used politically in both these causes. In the early seventeenth century Galileo was a relatively minor irritant to a Church which, while it saw danger in science, was willing to accept change — But not too quickly, and on its own terms. It is also the case that modern science is the product of a Christian culture, but that is a topic for other scholars.