MARCH, 1816. Vol. XLI., No. 480. THE ANALYST. OBITUARY. HENRY ENFIELD ROSCOE. THE name of Sir Henry Roscoe will always stand out as that of one of the most able and successful pioneers of the advancement of science, and particularly of chemistry, during the long period of his activities. I t is not easy to-day to realise the conditions that obtained in the teaching and practice of chemistry, and in the status of those associated with the science, when Roscoe commenced his life’s work as Professor of Chemistry at the Owens College, Manchester, in 1857.There were then but few institutions outside London where The necessity of scientific in- struction as a basis for industrial work was barely recognised, and the status of those engaged in either the teaching of chemistry or in chemicd industry was considerably below the none too high level it has since attained.In the changes that have taken place during the intervening period of some sixty years, Roscoe played a prominent pert. As a teacher he founded the leading school of chemistry in the country, which through his students did a great work in promoting the advancement of the science and of its industrial applications.By his writings and public lectures he spread an appreciation of the national importance of chemistry, and by his active associatiou with scientific soctieties he aided, with conspicuous success, the oo-operation of all workers in the science for their mutual benefit. Apart from his more direct services to chemistry, Roscoe did muuh for the promotion of University and of technical education both in Lancaehire and subse- quently in London.The University of Manohester, which has arisen from the old foundation of Owens College, owes much to his labours and marked powers of organisation ; and the period of his Vice-Chancellorship of the University of London (1896-1902) was characterised by valuable and progressive work during a difficult stage of transition from an examining body to a teaching University.As Member of Parliament for South Manchester from 1885 to 1895, his influence was chiefly concerned with the promotion of scientific and technical education. During the later years of his life he devoted much time to the organisation of the Lister Institute of Preventive Medicine; he was the first Treasurer and subsequently Chairman of its Governing Body, and held the latter ofice until his death.I n each of these spheres of activity the work accomplished and the sound basis laid for further development will remain as a lasting tribute to Roscoe’s labours. training in chemical science could be obtained.64 OBITUARY : HENRY ENFtELD ROSCOE Here it must suffice to refer to them only as an indication of the wide scope of his sympathies, which may help somewhat in the appreciation of his more specific work as a chemist.Henry Enfield Roscoe was born in London on January 7, 1833. When nine years of age he was sent to the High School of the Liverpool Institute, to which city his father had moved shortly before his death in 1836. I t is exceptional that a school curriculum in those days should have included some instruction in science, and fortunate that it should have fallen to Roscoe’s lot to have had Balmain, the discoverer of luminous paint and of boron nitride, as his inetructor, for from him Roscoe appears to have received his first impulse towards the study of chemistry.I n 1848 he entered University College, London, where he studied first under Graham and subsequently under Williamson, with whom he acted for a short time as private assistant.During this period Roscoe decided to adopt chem,Jtry as his profession, and after taking the degree of B.A. in 1853 he went to Heidelberg to continue his studies under Bunsen, who was then in the prime of his labours as a teacher and as an investigator. Heidelberg was at that time a very active centre of scientific worth. Kopp, Kirchhoff, and Kekulb, were on the staff of the University, and Roscoe’e fellow-students included Von Baeyer, Beilstein, Atkinson, Lothar Meyer, Russell, Pebal, Pauli, Quincke, Mathiessen, and Landolt.This stimulating atmosphere of workers had a great influence in moulding Roscoe’s future career end the character of his work, whilst it laid the basis of many lasting friendships. After a course of advanced quantitative analysis, followed by the study of the well-known accurate methods of gas analysia which had been worked out by Bunsen, Roscoe took his Ph.D.degree, and the0 commenced his classical photo-chemical invedigations with Bunsen, which were continued during many subeequent long vacations.On his return from Germany in 1855, Roscoe acted as oflicial assistant to Williamson a t University College for a short time, and subsequently set up as a consulting chemist in conjunction with his friend Dittmar. There is little reccrd of the dxtent of his professional prdctice, which was cut short in 1857 by his appoint- ment to the Chair of Chemistry in Manchester, in succession to the late Sir Edward Frankland.It is interesting to recall that the late Dr. Crace Calvert and the late Dt.. Angus Smith were among his unsuccessful competitors for this post. The Owens College, which had been founded by John Owens in 1848, was then in the throes of a struggling infancy-in fact, Roscoe speaks of it as “nearly in a state of collapse.” The premises in Quay Street, at that time anything but an attractive district of Manchester, consisted of a small house, of which the only title to distinction was that it had previously been the residence of Richard Cobden.The endowment was inadequate, and the status of the institution in the mind of the public may be gauged from the fact that Roscoe was refused the tenancy of a house by the landlord on the ground that the College would probably close its doors within a year.The total number of students was thirty-four, of whom fifteen were working in the laboratory which had been fitted up by Frankland ; and the appreciation by the trustees of the value of imtruction in science is indicated by the stipend of the Chair of Chemistry being fixed at one-half of that of the other professorships !OBITUARY : HENRY ENFIELD ROSCOE 65 These unattractive proapects served but to stimulate Roscoe and his colleagues to establish the value of science as an efficient instrument of education, and of such education as a necessity for an industrial career.It was hard uphill work for many years, but a wide and liberal educational outlook, a full sympathy with and under- standing of the prevailing industrial conditions, and an exceptional power of winning the interest of others, gradually gained the day.Year by year the number of students increased, and within fifteen years the Chemistry Department of Owens College had gained a European reputation, which continued to grow during the remaining fifteen years Roscoe remained as its director, and which he handed, on his retirement, as a splendid legacy, to the College and to his successor in the Chair, Professor H.B. Dixon. In this great work Roscoe received invaluable aid, which he always most fully acknowledged, from his colleague, Carl Schorlemmer, who first came to him as his private assistant in succession to Dittmar, and who was subse- quently appointed to the first and, for a long time, the only Chair of Organic Chemistry in the country.It is as a teacher, above all else, that Roscoe will always stand pre-eminent. He possessed that real love for his science which is the hall-mark of every great teacher, and he imbued his students with a like spirit. Many who attended his first year’s course of Iectures as a preliminary study to their further work were attracted from indecision or from the study of other subjects they had originally in view to make chemistry their profession, and it is no exaggeration to say that this influence led some of the best students of the College to the Chemistry Department.Once within its portals, Roscoe’s sincere personal interest in their progress and his stimu- lating influence as their teacher retained them as his disciples both during and long after their college days.For Roscoe’s care of his students never waned ; his interest in their work and welfare was always retained, and his valued friendship remained a constant encouragement throughout their careers. It was their privilege to record their gratitude to him on his resignation of the Manchester Chair, on the occasion of the jubilee of his doctorate, and finally on the attainment of his eightieth birth- day, when his bust was presented by them to the Chemical Society.The addresses presented to him on each of these occasions show how affectionately he was regarded by his students, and how highly tbey prized his counsel and example. The methods of teaching adopted by Roscoe were to a large extent the outcome of his experience in Bunsen’s laboratory.He was from the start a firm believer in the view that it is in the laboratory rather than in the lecture-room that the real teaching of chemistry must take place, and this principle was the basis of his system of instruction. It was his custom to give two courses of lectures each session, one to junior and one to senior students, each of which was replete with experimental illustrations.Roscoe was always an interesting if not a brilliant lecturer ; he had the faculty of treating his subject-matter simply and directly, and a marked gift of encouraging his students to further inquiry and study. The laboratory curriculum consisted of a course in qualitative analysis, followed by quantitative analysis, with subsequent organic and technical work and research, which were developed with the gradual growth of the school.His view of laboratory teaching was that it must66 OBITUARY : HENRY ENFIELD ROSCOE inculcate method and accuracy, so that the student should gradually gain the power of exact observation and logical inference, and that a thorough practical acquaint- ance with qualitative and quantitative analysis must form the basis of the proper education of the chemist, whether for purely scientific or for technical purposes.There is no need to accentuate the soundness of his views. They hold with full force still, despite an interval of anti-test-tubing-revolt. No better indication can be given of the secret of Roscoe’s great success as a teacher than to quote his own view of the functions of a professor, as stated in the record of the work done in the Chemistry Department of Owens College, whioh he published at the time of his retirement.In speaking of his plan of laboratory teach- ing, he says: “The personal and individual attention of the professor is the true secret of success ; it is absolutely essential that he should know and take an interest in the work of every man in his laboratory, whether beginning or finishing his course.The professor who merely condescends to walk through his laboratory once a day, but who does not give his time to showing each man in turn how to manipulate, how to overaome some difficulty, or where he has made a mistake, but leaves all this to be done by the demonstrator, is unfit for his office, and will assuredly not build up school.” How fully Sir Henry practised what he preached will be well remembered by his students.Each morning after his lecture he went into the laboratories, helping and advising and, above all, interesting each student in his work, and with fascinating personal recollections of great chemists and stories of new discoveries making the science real and living to all.I n his recognition of the importance of research, Roscoe was much in advance of his time, and throughout his life he missed no opportunity of accentuating its national and educational value. He encouraged it among his assistants and students both by example and by the provision of facilities for its prosecution, with the result that many more original investigations were published from the laboratories of Owens College during the thirty years of his professorship than from any other laboratory in the kingdom. Roscoe’s own contributions to science commenced with the researches he caxried out with Bunsen on the chemical action of light.These investigations laid the basis of aofinometry, and have played an important part in the more modern developments of quantitative photo-chemistry, An initial study of Wittwer’s experiments on the action of light on chlorine water led to the construction of the hydrogen and chlorine actinometer, which they established as a satisfactory instrument for the measurement of photo-chemical action.During the progress of this work Roscoe was considerably perturbed by the discovery that Draper had previously devised a somewhat similar instrument-his ‘‘ Tithonometer ” - a n d wrote at once to Bunsen on the subject, In an encouraging reply, which may similarly merit the appreciation of the younger chemists of to-day, Bunsen said : “ It appears to me that the value of an investiga- tion is not to be measured by whether something is described in it for the first time, but rather by what means and methods a fact is proved beyond doubt or cavil, and i n this respect I think that Draper has left plenty for us to do,” Bunsen and RoscoeOBITUARY : HENRY ENFIELD ROSCOE 67 pointed out the errors associated with Draper’s instrument, and fully proved the greater accuracy of their own form of actinometer.They subsequently devised the first satisfactory method for the preparation of silver chloride papers of constant sensitiveness, the darkening of which was compared, for actinometrical measure- ments, with a scale of standard tints prepared from zinc oxide and lampblack. This form of photographic actinometer was modified at a later date by Roscoe by adopting darkened silver chloride papers, fixed by sodium thiosulphate, as the scale of com- parison. By these means they studied the relation of the f m e and intensity of action of light to the photo-chemical effect, and the conditions of absorption of the actinic rays, and made measurements of the photo-chemical action of diffuse daylight, direct sunlight, and of the distribution of actinic rays in the solar spectrum.This work led to the discovery of the phenomenon of photo-chemical induction, a problem of very great interest, which they investigated with much care and skill. It has been the subject of much subsequent research which has proved that the delay in the combination of hydrogen and chlorine is due to the inhibiting effect of impurities, in the absence of which there is no period of induction.The inclusion of these photo-chemical researches of Bunsen and Roscoe in Ostwald’s ‘‘ Klassiker der exacten Wissenschaften ” is a fitting measure of their importance and value. Shortly after his appointment to the Manohester Chair Roscoe commenced his work on the composition of aqueous acids of constant boiling-point. The results obtained with the halogen acids either by distillation or by the passage of a current of air are well known, It may be of interest to add that aqueous solutions of nitric, sulphuric, formic, acetic, and perchloric acids were similarly investigated.From the last of these Roscoe was led to hig study of perchloric acid, which had not been obtained pure until he prepared it by the decomposition of the pure potassium salt with sulphuric acid.He determined its composition and that of its potassium salt, and subsequently studied the isomorphous relations of the perchlorates of potassium, ammonium, and thallium. In 1865 Roscoe commenced his classical investigations on vanadium. This work originated from a visit to the copper-mines at Mottram, near Alderley Edge, in Cheshire, where the copper occurs together with other metals, notably cobalt, in the form of carbonate, as an incrustation over the grains of Keuper sandstone.The process of extraction consisted in treating the ore with hydrochloric acid, and subse- quent precipitation of the copper with metallic iron or zinc. On the occasion of Roscoe’s visit he was shown a dark blue solution which was regarded as a concen- trated solution of copper salt, in a peculiar condition, inasmuch as it was not pre- cipitable by zinc. He concluded at once that the blue colour must be due to the presence of some metal other than copper, and soon confirmed his first suspicions that it was due to vanadium.He subsequently obtained a good supply of 8r lime precipitate from this source, from which he prepared a considerable quantity of vanadium oxide, which served as the starting point for his work.Vanadium was first investigated by Berzelius in 1831, who, although he had only a few grams of material at his disposal, succeeded in preparing, with characteristic skill, a large number of vanadium compounds, from the study of which he concluded that the metal was closely allied to chromium and molybdenum, forming an acidic68 OBITUARY : HENRY ENFIELD ROSCOE trioxide and an acid chloride.By heating this chloride in an atmosphere of ammonia, Berzelius obtained brilliant metallic scales, which he regarded as the metal, and he based his determination of the atomic weight of the element upon the relationof the acid chloride and of the acidic oxide to the reduction product of the latter.Roscoe, however, showed that the substance regarded by Berzelius as vanadium was, accord- ing to its method of preparation, either a nitride or an oxide, and that the acid trichloride was really an oxychloride analogous to that of phosphorus. He prepared the pure metal by reducing the dichloride, VCI,, by means of hydrogen, and deter- mined its atomic weight from the ratio V,O, : V,O,, as ascertained by reduction in hydrogen, and also from the ratios VOCI, : 3Ag and VOCI, : 3AgCI.The mean values of these results, calculated on the present atomic weights, were 51.38, 51.05, and 51.26, respectively. The most recent determinations” give the atomic weight as between 50.93 and 50.97, so that the figures obtained by Roscoe so many years previously indicate the accuracy of his work.From these results, as well as from his study of the composition of the vanadium compounds, of which he prepared a large number, Roscoe concluded that vanadium belongs to the nitrogen and arsenic family, and thus succeeded in placing it in its accepted position in the fifth group of the periodic classification. These researches formed the subject of the Bakerian Lecture before the Royal Society in 1868, and received further recognition in the award, by the Society, of a Royal Medal in 1873.Roscoe’s other contributions to science stand in a somewhat subsidiary relation to the above important investigations. These include the determination of the vapour density of the chlorides of lead and of thallium ; the discovery of the pentachlorides of tungsten and of uranium ; and the proof that the so-called element ‘‘ phillipium ” was really a mixture of terbium and erbium. He also, in conjunction with Schuster, mapped the spectrum of terbium salts, and, in conjunction with Thorpe, studied the absorption spectrum of bromine and of iodine chloride.It is not only with those who worked in his laboratories that Roscoe exerted his influence as a teacher.His writings extended this influence to a far wider sphere. Both in this country and abroad they have, for many years, formed a basis for the teaching of chemistry in schools and colleges. Roscoe was endowed with much literary ability, a gift inherited from his father, Henry Roscoe, an able barrister and the author of several standard works on law, and from his distinguished grandfather, William Roscoe, so well known by his (‘ Life of Lorenzo de Medici ” and of ‘‘ Leo X.” Roscoe’s style is marked by lucidity and simplicity of expression, and in the selection of his subject-matter he avoided, with exemplary success, the tendency towards an unattractive compilation of data which is too often the characteristic of more modern textbooks and treatises on science.At the time of the publication of the Lessons i n Elementary Chemistry,” in 1866, there were scarcely any books of the kind in existence; a small textbook by George Wilson, and the larger and more expensive works by Fownes, Graham, and Miller, appear to have been the only books available for the use of students.That * H. V. A. Briscoe and H. E. V. Little, J. Chena. Soc., 1914, 105, 1310.OBITUARY : HENRY ENFIELD ROSCOE 69 the “Lessons ” met an acknowledged want, and did much to promote the teaching of chemistry, is shown by the remarkable demand that followed its original publica- tion and that of the many successive editions. They were translated into German by Schorlemmer with an equally successful result, and into no fewer than nine other languages, including Polish, Hungarian, Modern Greek, Japanese, and the Indian vernacular, Urdoo.At a somewhat later date, Roscoe, in conjunction with Huxley and Balfour Stewart, undertook the editorship of a series of simple books on elementary science, the ‘( Science Primers,” and contributed the volume on Chemistry.This little work did excellent service as a first step in chemistry for schoolboys, and, like the ‘‘ Lessons,” was translated into many other languages. These works were followed, in 1877, by the “Treatise on Chemistry,” in tbe publication of which Roscoe enjoyed the valued co-operation of his colleague Scborlemmer. I t has long been a standard textbook of Inorganic Chemistry, and its value has been repeatedly enhanced from edition to edition, by careful revision and additions, without destroying the essential characteristics which contributed so fully to its initial success.I n the revision of the later editions Roscoe received the help of several of his former students and others; but even in the preparation of the last editions, which were published but a few years before his death, he supervised the whole of the work with the greatest care and judgment and with enviable mental vigour.The portion of the treatise devoted to Organic Chemistry was never completed. This was in part due to the death of Schorlemmer, but chiefly to the fact that the modern develop- ments of this branch of the science became unsuitable for adaptation to the original plan of the book.The German edition of this portion of the work has, however, been carried to completion under the direction of Bruhl. Other literary work includes the ‘‘ Lectures on Spectrum Analysis,” published in 1869, a series of lectures which were originally given in the Hall of the Apothecaries’ Company, and which did much to arouse interest in the pioneer work of Bunsen and Kirchhoff on this subject.This book has also proved its merit by the call for suc- cessive editions, the later of which were published in conjunction with Schuster. Roscoe’s long association with Manchester not unnaturally directed his interedi t o the life and work of his townsman, John Dalton, several of whose manuscript laboratory and lecture notebooks he unearthed from among the archives of the local Literary and Philosophical Society.The examination of these papers revealed a number of historical data which shed an entirely new light on the origin of the atomic fheory, and showed how much more Dalton had relied upon philosophic reasoning from physical considerations than on his experimental data, in arriving a t his fundamental hypothesis.The views arising from these discoveries were published by Roscoe, in co-operation with Harden, in a volume entitled ‘‘A New View of the Origin of Dalton’s Atomic Theory.” He also wrote a life of Dalton for the Century Series of Scientific Men. Sir Henry added a welcome coping-stone to his literary work by the publication of his autobiography in 1906, under the title of his “ Life and Experiences.” The story of his career, his work, his friends, and his home, is told with characteristic The (‘Treatise” is too well known to need comment.70 PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS simplicity and charm. It is a book that will tell future generations something of the personality and labours of a great and good man. Roscoe was awarded many honours both by his fellow-scientists and by his country. He was elected a Fellow of the Royal Society in 1863; in 1879 his name was added to the restricted roll of honorary members of the German Chemical Society; he was the recipient of many honorary degrees, and served as President of the Chemical Society, the Society of Chemical Industry, and of the British Associa- tion. He received his knighthood in 1884, and the signal honour, for 6 scientist, of a Privy Councillorship was conferred upon him in 1909. Death came to him as he would have wished, a quick and peaceful passing, free from pain. He died at his residence, Woodcote Lodge, West Horsley, on Decem- ber 18, 1915, within a few weeks of his eighty-third birthday. CHARLES A. KEANE.