Alexander Crum Brown was born in Edinburgh on 26 March 1838 the only son of Dr. John Brown, a minister, and Margaret (nee Crum). His father was twice married; his son by the first marriage was John Brown, M.D., well known as an Edinburgh physician but who earned a wider fame as the author of 'Rab and his Friends'.  His mother's brother, Walter Crum, F.R.S., was a chemist of note and may have influenced Crum Brown's choice of chemistry as a career.¹ Crum Brown was a precocious child, always busy with models and inventions. Before he was of school-age he had made a practical machine for weaving cloth, an early indication of his life-long interests in knots and complicated systems of knitting. He was educated in the Royal High School, Edinburgh, followed by one year at Mill Hill School. In 1854 he entered the University of Edinburgh as an Arts student; he attended Gregory's Chemistry class and was Class Medallist, and he graduated M.A. in 1858.  He then studied medicine graduating M.D. in 1861. During the same time he read for the science degree of London University, and in 1862 he had the distinction of being the first candidate on whom the Doctorate of Science of London University was conferred. After medical graduation in Edinburgh he studied chemistry in Germany. first under Bunsen at Heidelberg, and then under Kolbe at Marburg.

In 1863 he was licensed as an Extra-Academical Lecturer in Chemistry by the University of Edinburgh. Each winter session, he gave "a systematic course of Lectures on Chemistry, and taught Practical and Analytical Chemistry" . Each summer session he gave a special course of lectures on "one of the higher departments of Chemistry, or on Crystallography". ² His classes were small, sometimes consisting of only two students. Thus he had ample time for research which he used very profitably so that when, on Playfair's resignation, he applied for the Edinburgh Chair of Chemistry he received the support of nearly all the prominent British chemists and also of many Continental chemists, a total of 39, and also of 12 men of other scientific disciplines.² All previous appointments to the Chair had been made by the Town Council but since the Universities (Scotland) Act of 1858, which essentially set up the University structure as it exists today, appointments to most Chairs were made by the Curators of Patronage. There were seven Curators, four nominated by the Town Council and three by the University Court; today four Curators are nominated by the Court and three by the Town Council. The 'Edinburgh Evening Courant' of 15 April 1869 reported as follows:

"UNIVERSITY OF EDINBURGH -CHAIR OF CHEMISTRY -
Yesterday, at a meeting of the curators of the University of Edinburgh, Dr. Alexander Crum Brown, who has for some years been an extra-academical lecturer on chemistry in this city, and well-known for his valuable contributions to science, was appointed to the Chair of Chemistry in room of Mr. Lyon Playfair, M.P., resigned".

The many applicants included William Perkin, the pioneer of synthetic dyestuffs. Crum Brown was elected a Fellow of the Royal Society of Edinburgh in 1864 and served on the Council for a total of forty-four years, for twenty-six of which he acted as one of the secretaries, and for six as a vice-president. He was elected a Fellow of the Royal Society of London in 1879, was President of the Chemistry Section of the British Association in 1874, and President of the Chemical Society from 1891 to 1893. He retired from the Chair of Chemistry in 1908. Early in his professorial life he had married Jane (nee Porter) whose death two years after his retirement overshadowed the last decade of his life. Failing health confined him to the house, though his mind lost little of its activity, and he died peacefully on 28 October 1922, "leaving to all who knew him a legacy of very pleasant memories". ¹

Crum Brown's main scientific work was done while he was young and bears a marked individual stamp. His mind was essentially philosophic and speculative. His M.D. thesis was entitled "On the Theory of Chemical Combination" and showed him to be a pioneer in scientific thought. In it he developed a system of graphic formulation of compounds which is essentially identical with that used today. His formulae were the first to show clearly both the valency and the linking of atoms in organic compounds. Some chemists quickly adopted Crum Brown's graphic formulae, e.g. four years later Edward Frankland used them throughout his entire course, considering that they had several important advantages over Kekule's. Towards the conclusion of his M.D. thesis he wrote

"It does not seem to me improbable that we may be able to form a mathematical theory of chemistry, applicable to all cases of composition and recomposition".

He was repeatedly to return to this theme.

In 1864 he published an important paper on the "Theory of Isomeric Compounds" [see opposite], in which, using his graphic formulae, he discussed the various types of isomerism, paying special attention to fumaric and maleic acids. ³ In 1867 in continuation of his systematic work he published a paper "On the Classification of Chemical Substances by means of Generic Radicals".⁴ His breadth of knowledge is shown by a paper in 1867 "On an Application of Mathematics in Chemistry" and in 1868 by a pioneering investigation of fundamental importance on the connection between chemical constitution and physiological action.

For some time after his appointment to the Chair he published little but in 1873 he began a series of investigations of the organic sulphur compounds, particularly derivatives of trimethyl-sulphine, which occupied him for several years. In 1890 he entered a new period of chemical activity with a theoretical paper on the relation of optical activity to the nature of the radicals bonded to the assymetric carbon atom.⁵ About the same time he began a series of researches on the synthesis of dibasic acids by the electrolysis of ester-salts. ⁶ In 1892, in conjunction with John Gibson, he published the well-known rule for determining the position in the benzene nucleus taken up by an entering radical with respect to one already present. ⁷

Despite its high calibre, Crum Brown's work received scant recognition partly because through loyalty to the Royal Society of Edinburgh he published nearly all his researches in the Society's 'Transactions' and 'Proceedings' whose circulation among chemists was very limited. In addition to his chemical work he made valuable contributions to physiology and published several careful papers on certain branches of mathematics. Outwith science his breadth of knowledge was also exceptional extending to philology, church history, and modern languages including Russian and Chinese. He was reputed by his contemporaries to be capable of "filling any Chair in the University". ⁸

Crum Brown was convinced that chemistry would one day achieve the perfection of a mathematical science. In his presidential address to the Chemical Society in 1892 he emphasised the importance of mathematics to the chemist in the following words:

"The chemist will still be the man trained in the chemical laboratory, and all the mechanical parts of the work will be done by him. But unless he learns the language of the empire [mathematics], he will become a provincial, and the higher branches of chemical work, those which require reason as well as skill, will gradually pass out of his hands".

ln a letter of 5 March 1886, Crum Brown wrote that chemistry was not yet so far advanced as to have a Newton,

"what we are waiting for is a man who will show how the Laws of Motion can be applied to Chemistry, for Chemistry is only an independent Science because we do not yet see its full relation to the general Science of Dynamics. Our present work is to prepare the way for such a man".⁹

Crum Brown had, many years before the experimental elucidation of crystal structures, very modern views on the solid state. In the article 'Molecule' of the 1883 edition of the 'Encyclopaedia Britannica' he wrote:

"It is perhaps scarcely correct to speak of a molecular structure of [crystalline] solids at all. Solids are no doubt composed of atoms and those atoms are evidently arranged in what may be called a tactical order. When the solid is fused or dissolved or volatilised, it breaks into molecules, each repetition of the pattern being ready to become an independent thing under favourable circumstances".

Crum Brown's obituarist and successor, James Walker, recorded that many years before the work of Laue or Bragg, Crum Brown, in conversation with him, mentioned that he had constructed a model of the structure of sodium chloride, each chlorine atom having six equidistant sodium neighbours and each sodium atom six equidistant chlorine neighbours. ¹ The model, constructed in characteristic Crum Brown fashion from knitting needles and alternate balls of red and blue wool, is preserved in the museum of the Chemistry Department of the University of Edinburgh. The nucleus of the Departmental museum is a collection of chemicals used by Lyon Playfair in illustrating his lectures and presented to the University on his resignation from the Chair of Chemistry; over the years the museum collection has from time to time been increased in a somewhat haphazard fashion and contains other Crum Brown artefacts such as complicated pieces of knitting in illustration of his mathematical work on inter-penetrating surfaces.

As a teacher, to the average elementary student his lectures were rather a trial. A former pupil of his wrote:

"Briskly entering the class-room, he began at once in rapid phrasing to describe the properties of a chemical substance or the intricacies of a chemical process. Chemical formulae grew like magic on the black-board. The casual and limp-minded listener found Crum Brown's quick vivid style much too strenuous; but the student who really wished to learn, and had ear and eye in well-trained attention, could not fail to experience keen intellectual delight from the masterly manner in which the whole subject was presented".¹

One point of interest about the content of his lectures is that the then new physico-chemical theories of osmotic pressure and of electrolytic dissociation aroused his interest and, becoming gradually convinced of their validity, he did much to place them clearly before his students. However Crum Brown's lecturing style was not conducive to maintaining order in a large class and a Senatus Minute of 1871 refers to "Disturbance in Chemistry Classroom" ; the culprit "was fined one guinea; and (without being put formally on his probation) he was warned that any repetition of the same conduct would be more severely punished". David Rorie wrote of the chemistry class:

"But Crum Brown's was the noisiest in medicine and was often the scene of back-bench hooliganism. His high pitched voice, his mannerisms, his frequent and stereo-typed appeals to the non-existent better nature of his interrupters, and the very kindness of his heart, all made for lack of order". ¹⁰

Crum Brown was kindly, generous and modest, and these qualities came through to the students so that affection for "Crummie" is a recurring theme in student reminiscences. John Flett wrote:

"Crum Brown was a charming man and a very bad teacher. Most of his students very soon gave up all attempt to follow him and the class was exceedingly rowdy. Some days the noise and interruptions were so great that the poor professor had to give up and flee. Then in a few minutes he would return with tears streaming down his cheeks and apologise for his inability to control his class. We all loved him". ¹¹

Francis Bell wrote that Crum Brown's intellectual reputation

"gave him an aura set off by his personality; his venerable stooped figure and the contrast provided by his white beard and hair, and skull cap and the sparkling vitality of his black eyes. In spite of all this a rowdy, genial disorder prevailed and when the row became intolerable, he would depart to his retiring room. A fervent chorus of "Will ye no' come back again" followed and after a suitable interval, back he came. I think he really enjoyed our bizarre show of affection and teasing. The story of his fall entering the classroom and his remark on picking himself up "just a brown precipitate, gentlemen" I cannot vouch for".¹²

Crum Brown's particular teaching strength was his lectures on organic chemistry to advanced students. He selected a few topics and dealt with them in detail in such a way as to make them relevations of the working of the scientific method. The notes taken by James Walker of Crum Brown's organic lectures are preserved in the Library of the University of Edinburgh and fully bear out the above view.¹³

Within the University Crum Brown was a valued administrator. He was a prominent member of the University Court for many years. He long acted as convener of the Science Committee of the Senatus which was responsible for the Degrees in Science until the establishment of a Faculty of Science in 1893.

During Crum Brown's tenure of the Chair there were a number of changes which together may be regarded as the first phase in the evolution of a Department of Chemistry as understood today. Before the Universities (Scotland) Act of 1858 the only University teachers were the Professors who, where appropriate, as in Chemistry, privately employed assistants to help in, for example, the preparation of lecture demonstrations. The 1858 Commissioners were favourably impressed by the work done by private assistants and provided funds for University Assistants to be attached to the chairs most in need of help, and the first Assistants in Chemistry were appointed in 1862. One of the most distinguished of Crum Brown's early Assistants was James Dewar, invited to the Chair of Natural Philosophy in Cambridge, who while at Edinburgh discovered the use of charcoal in the production of high vacua and laid the foundation of his later work on the liquefaction of gases and the production of low temperatures. ¹⁴ In 1876 the staff comprised two Assistants for whom the University provided £200 a year of which £100 was paid to the demonstrator of practical chemistry and £100 to the chief Assistant in the laboratory who also received £50 from Crum Brown; there was also a privately employed lecture assistant who received £100 per annum; the Hope Prize Fund provided a scholarship tenable for one year of about £30 which was awarded to the best student of practical chemistry and the holder was bound to assist the professor in the laboratory and was given certain restricted duties which would not unduly interfere with his studies; there were also three privately employed servants who were paid a guinea a week throughout the year.¹⁵

Up to 1858, Old College, built between 1789 and 1833, housed the entire University. As early as 1832 the architect W.H. Playfair considered the chemical laboratory to be inadequate and by Crum Brown's time it was officially described as "little better than a kitchen".¹⁶ The first new building was the Reid School of Music built in 1858 and the second new building, much more significant in relieving the pressure on space in Old College, was the Medical School in Teviot Place. Planning began in 1874 when the nine Professors, including the Professor of Chemistry, who were to be provided for were asked to specify their requirements. Between 1880 and 1884 the Faculty of Medicine transferred from Old College to its new building. The Chemistry rooms in Old College were, before the start of the 1884-5 session, handed over to Zoology and in that session Chemistry transferred to the north-west corner of the new buildings, where two Lecture Rooms and the Practical Chemistry Class Room had been completed. The larger of the two lecture rooms had seats for 400, and the smaller for 120. In the Practical Chemistry Class Room, intended chiefly for medical students, about 100 working places were provided.  The General Chemical Laboratories and the numerous ancillary rooms were opened in the summer of 1885. These laboratories were intended for students able to devote from 2 to 7 hours daily to practical work, with a view to taking chemistry as a special subject in their Science Degree curriculum or qualifying themselves for situations as practicing chemists; working places were provided for forty students, this accommodation being far in excess of the requirements at the time. These new laboratories were at first equipped mainly for analytical chemistry but as the need arose ancillary rooms were equipped for such techniques as gas analysis, physico-chemical methods, and electrolytic analysis. The number of students working in the Chemical Laboratories gradually increased from about 27 in 1885 to about 70 in 1900 and during 1903 an extensive addition was made by adding a floor above the existing laboratories which provided forty additional working places, a balance room, and for the first time an office for the assistants. The enlarged facilities were open to visitors on 4 January 1904 and a small descriptive booklet, proudly entitled "CHEMISTRY DEPARTMENT",was provided.

With the new laboratories of 1885 came postgraduate workers, one of the first being James Walker who after graduation in 1885 continued to work in the laboratory; among the few fellow-workers were Hugh Robert Mill, P.C. Ray, Alexander Smith, subsequently Professor at Columbia University, and David Orme Masson, subsequently Professor in the University of Melbourne. ¹⁷ With the growth of chemistry the number of assistants increased and in 1890 there were five, Leonard Dobbin, John Gibson, Hugh Marshall, Alexander Smith, and James Walker. They lunched together in a dark and dismal room in the basement and constituted themselves into a club, the Alembic Club, which arranged meetings outside working hours to discuss chemical problems of interest. Later they undertook the publication of fundamental papers of historical interest under the title of "Alembic Club Reprints". Leonard Dobbin, the club secretary, played the chief part in this venture which was very successful. The Alembic Club is now under the aegis of the Royal Society of Edinburgh.

Important changes in the University were inaugurated by the Universities (Scotland) Act of 1889. The Act opened the University to women for graduation and admitted them to the regular classes on equal terms with men. The Faculty of Science was established in 1893 with James Geikie, Professor of Geology, as its first Dean. Changes were made in the regulations for Degrees in Science; the 2-year curriculum for the B.Sc. Degree became a 3-year curriculum of 7 courses; 3 courses were taken in First Year and during Second and Third Years four courses in one of which it was necessary to specialise; the Degree of D.Sc. was awarded primarily on a thesis based on original research and not as hitherto by examination. The appointment of Lecturers, of whom before 1889 there were very few, was regularised; in 1894 Leonard Dobbin who had been an Assistant since 1880 was appointed to the first Lectureship in Chemistry. The Professors were no longer to receive class-fees from the students but were appointed with regular salaries; the salary of the Professor of Chemistry was fixed at £1400 p.a. but during Crum Brown's tenure of the Chair was to be £1828 in line with what he had been receiving under the class-fee system.

During Crum Brown's tenure of the Chair, Chemistry passed from being 'a man and a boy' to a small Department similar in many respects to a modern Department of Chemistry. During Crum Brown's first year, the teachers were himself and two Assistants, there was one lecture course primarily for medical students, there was only one student for the degree of B.Sc. in Physical Science, the chemical laboratory was 'little better than a kitchen' and there were no research workers. By contrast in the year of Crum Brown's retirement, the academic staff consisted of the Professor, 3 Lecturers and 4 Assistants; the courses were (i) the elementary course primarily for medical students but now containing a number of students intending further study in chemistry, (ii) a course in organic and advanced inorganic chemistry for students, about 25 in number, taking chemistry for the Final B.Sc. Examination, and (iii) advanced courses, for those three or four students specialising in chemistry, on Chemical Theory and History of Chemistry, Mineralogy and Crystallography, and Physical Chemistry; the undergraduate laboratory work, in addition to analysis, consisted of the preparation of pure substances and examination of their properties, and physico-chemical experiments; there were research laboratories and several joint papers by Crum Brown and research workers had been published.  It is not surprising that Crum Brown viewed his retirement with mixed feelings writing in a letter of 12 July 1908:

"I am just now engaged in climbing up to the shelf and in 13 days I shall be emeritus. I don't know whether I should laugh or cry - probably I shall do neither - or both. At present I have enough to do disentangling myself, and there are still the examinations between me and repose". ¹⁸

1. Walker, J., Journal of the Chemical Society, 3422-3431 ( 1923).
2. Testimonials in favour of Alexander Crum Brown (Muir and Paterson, Edinburgh,1869).
3. Brown, A.C., Transactions of the Royal Society of Edinburgh, 23,707-720 (1864).
4. Brown, A.C., ibid.,24, 331-9 (1867).
5. Brown, A.C., Proceedings of the Royal Society of Edinburgh, 17, 181-5 (1891 ).
6. Brown, A.C. and Walker, J., Transactions of the Royal Society of Edinburgh, 36,211-224 (1892); ibid., 37,361-379 (1895).
7. Brown, A.C. and Gibson, J., Chemical Society Transactions, 61, 367-9 (1892).
8. Horn, D.B., A Short History of the University of Edinburgh (University Press, Edinburgh, 1967), p. 194.
9. National Library of Scotland MS 2636, f. 182.
10. Rorie, D., University of Edinburgh Journal, 6,8-15 (1933-34).
11. Flett, J.S., ibid., 15,160-182 (1949-1951).
12. Bell, F.G., ibid., 20,215-230 (1961-1962).
13. Edinburgh University Library MS Gen. 47D.
14. Kendall, J., Journal of Chemical Education, 4,565-9 (1927).
15. Report of the Royal Commissioners on the Universities of Scotland, vol. II (Evidence-Part I) (H.M.S.O., Edinburgh, 1878), pp. 184-5.
16. Quasi Cursores (Constable, Edinburgh, 1884), pp. 229-232.
17. Kendall, J., Obituary Notices of Fellows of the Royal Society, 1,537-549 (1932-35):
18. Edinburgh University Library MS Gen. 178/3,4.