John Oliver Arnold
Professor John Oliver Arnold (1858-1930) of Metallurgy, Sheffield University College. 
1911 Living at Broomfield, Sheffield: John Oliver Arnold (age 52 born Fletton, Hunts.), University Professor (Metallurgy). With his wife Adelaide Victoria Arnold (age 50 born Liverpool), Married 27 years with three children. Also two servants.
1930 Obituary 
Professor JOHN OLIVER ARNOLD, F.R.S., Emeritus Professor of Metallurgy in the University of Sheffield, died at Oxford on March 27, 1930, in his seventy-third year.
Born at Peterborough in 1858, he was educated at King Edward's School, Birmingham; he then joined H.M.S. Conway, intending to take up a seafaring career. However, after a voyage to India, he entered the Sheffield Steel and Iron Works (Brown, Bayley and Dixon's), where he actively pursued the study of metallurgy. He held several appointments in the laboratory and testing departments at local works, and was awarded a Telford Medal by the Institution of Civil Engineers in 1887.
In 1889 he was appointed Professor of Metallurgy at the Sheffield Technical School, and remained on the staff when that body was absorbed by the University; he effected, revolutionary changes in his department by giving increased attention to the science of metals, in which his investigations were of the greatest practical value. He remained at the head of the metallurgical laboratories of the Department of Applied Science of the University of Sheffield from its opening until he resigned his Professorship in 1920, and himself designed the metallurgical laboratories and steelworks.
He accompanied the British Association to South Africa as a special lecturer on steel in 1905; he was a member of the Standing Committee on Metallurgy of the Advisory Council of the Privy. Council, and was frequently consulted by the Admiralty.
In 1900 Arnold carried out at the instance of the late A. F. Wiener a systematic series of tests to determine the influence of vanadium on steel, and great merit is certainly due to him as a pioneer in making known the value of vanadium as an alloy constituent in steel and in the development of its use. Yet Arnold's claim to have been the discoverer of the influence of vanadium cannot be substantiated, as he was anticipated by four years by the Frenchman, K. Helouis, whose first systematic tests, in 1896, on the effect of vanadium in steel had attracted much attention at the time (Journ. I. and B.I., 1896, No. II. p. 418).
Arnold's subsequent researches at Sheffield on the molecular constitution of alloy steels and on the influence of all the principal metals used in the production of such steels led to notable improvements in the qualities of high-speed steels.
During his career as Professor of Metallurgy at Sheffield University he contributed fifteen papers to the Proceedings of the Institute, of some of which he was the sole author, while some were written by him in collaboration with others, notably the late Professor McWilliam. Of these papers he was accustomed to regard his first as perhaps the most important, namely, "The Physical Influence of Elements on Iron," published in 1894. A later paper on "The Microstructure of Hardened Steel," presented jointly with McWilliam in 1902, led to what was perhaps the most heated controversy ever witnessed at a meeting of the Institute. Professor Arnold was elected to Fellowship of the Royal Society in 1912, and was a Doctor of Metallurgy of the University of Sheffield. In February 1919 his health broke down and he was ordered complete rest for a year.
He was elected a member of the Iron and Steel Institute in 1901, a Member of Council in September 1916, and an Honorary Vice-President in June 1925.
"THE LATE PROFESSOR J. O. ARNOLD. The death of Professor John Oliver Arnold, D.Met., F.R.S., at Oxford, on March 27, after a long period of ill health, removes from the ranks of British scientists, a man of remarkable ability and achievements, who, in many respects, was a pioneer in the realm of scientific metallurgy. Since relinquishing the Chair of Metallurgy at the University of Sheffield, in 1920, Professor Arnold had been living in retirement at Bowness-on-Windermere, Westmorland. Probably the last honour paid to him was his election to an honorary vice-presidentship of the Iron and Steel Institute in 1925. His name thus appeared in company with those of Messrs. Percy C. Gilchrist and Alexander Pourcel, Professors H. Le Chatelier and Carl Benedicks, and other metallurgists of international renown.
The son of the late Mr. David Nelson Arnold, M.I.Mech.E., who was general manager of the Midland Railway Carriage and Wagon Company, Limited, Birmingham, for many years, Prof. Arnold was born at Peterborough on December 29, 1858, and received his early education at King Edward Vi’s Grammar School, Birmingham. With a naval career in view, he became a cadet in H.M.S. Conway, and subsequently embarked on a voyage to India. Although he remained an enthusiastic yachtsman all his life, he decided to give up the sea as a profession, and, at the age of twenty, entered the engineering department of Messrs. Brown, Bayley and Dixon, Limited, Sheffield, where he ultimately became chief chemist and test master. He then proceeded to Leeds, and, after spending some time with the Famley Iron Company, Limited, returned to Sheffield to take up the appointment of chemist and manager at the Spanish Steel Works, acting as the same time as consulting metallurgist and chemist.
At the early age of thirty-one, he was appointed acting-professor of metallurgy at the Sheffield Technical School, now the Applied Science Department of Sheffield University. His predecessor was the late Professor William H. Greenwood, A.R.S.M. Promoted to the full professorship in 1890, and Dean of the Faculty of Metallurgy in 1917, Professor Arnold retired owing to ill-health in 1920, and was nominated Emeritus Professor. The value of his researches upon the physical chemistry of steel was recognised by the Royal Society in 1912, when he was elected a fellow of that body. Professor Arnold became a member of the Iron and Steel Institute in 1901, was awarded the Bessemer Gold Medal in 1905, and was elected to the Council in 1915. In 1905, he. accompanied the British Association to South Africa as special lecturer on steel, and was President of the Sheffield Society of Engineers and Metallurgists from 1914 to 1918. He was also a member of the Standing Committee on Metallurgy on the Advisory Council of the Privy Council.
For a period extending over approximately thirty years, Professor Arnold; regularly presented contributions at the meetings of the Iron and Steel Institute, and took part in the discussions on very numerous occasions. He was a regular attendant at all the proceedings, and his invariable bonhomie enlivened them on many occasions. His keen sense of humour was, in fact, one of his foremost characteristics. He was held in great esteem by all his former students, many of whom have risen to important positions in academic and industrial spheres. Several of his students differed from him in later years, following upon their own independent investigations into metallography and allied subjects, but this had no effect upon their affection for their old teacher. Professor Arnold was twice awarded a Telford Premium by the Institution of Civil Engineers, first in 1887, for his paper “ On the Influence of Chemical Composition on the Strength of Bessemer-Steel Tyres.” On the second occasion, in 1895, he also gained a gold medal for his researches upon “ The Influence of Carbon in Iron.” In 1898, he was awarded a premium by the Institution of Engineers and Shipbuilders in Scotland for his lecture on “ The Internal Architecture of Metals.”
Steel Works Analysis, Professor Arnold’s only publication in book form, the first edition of which was issued in 1891, is undoubtedly from the pen of a master. We have no hesitation in saying that a well-thumbed copy of this work is to be found in almost every steel-works laboratory throughout the world. Four editions have been published, Dr. F. Ibbotson, lecturer in metallurgical chemistry at Sheffield University, collaborating in the last two. Theoretical considerations and practical manipulations are dealt with side by side, and all the complex reactions taking place are explained in a lucid style. The preface to the original edition contains one or two instances of the Professor’s dry humour.
The factor which caused Professor Arnold to come into prominence more than any other was his celebrated sub-carbide theory of hardening. The latter was advanced as an alternative to Osmond’s allotropic theory, which was first put forward in 1890. Osmond’s hypothesis consisted of the following essentials :—Three distinct allotropic modifications were discernible in pure iron when heated up to, say, 1,000 deg. C., or when cooled, through the same temperature range. These were termed, respectively, alpha, beta, and gamma iron, and the recalescence points, which determined the end of one allotropic modification and the beginning of the next, were designated Ap Aa and Aa. Above Ara (880 deg. C.), the iron was in the gamma condition ; between Ara and Ar, (750 deg. C.), the gamma condition was replaced by beta iron, and below Ara, and at normal temperatures, the iron was in the alpha allotropic state. Osmond stated that hardened steel, in his opinion,, owed its properties primarily to the presence of beta iron, which was hard and brittle at normal temperatures. His conclusion was that, when quenched from above Ara, and in passing rapidly from the gamma to the alpha zone, some of the iron was retained in the hard beta form. He seems to have recognised, however, that carbon played an important part, in that, in the form of hardening carbon, it imparted stability to beta iron. Under ordinary quenching conditions it was fairly easy to retain the carbon in the form of hardening carbon and, consequently, the all-important hardening agent, beta iron, could be successfully preserved at ordinary temperatures.
In energetic opposition to this hypothesis, Professor Arnold set out his sub-carbide theory in two able papers, first in 1894 and again in 1896. He cast grave doubts on the existence of the allotropic modifications, and maintained that combined carbon, alone, was responsible for hardening by quenching. He showed that, above Ara, a definite, though unstable, sub-carbide of iron existed which possessed a hardness equivalent to that of quartz. This was partially retained by very rapid cooling, thus imparting great hardness to quenched steels. After much research, he found that steels containing 0 • 89 per cent, carbon were, after quenching, entirely composed of this sub-carbide, which was a definite chemical compound corresponding to the formula Fe24C. These, he termed “ saturated steels,” and micrographic examination of slowly-cooled specimens showed them to consist entirely of pearlite, which, he stated, corresponded to the formula 21 Fe + FeaC. In his opinion, the critical points observed by Osmond and others, and verified by himself, were not due to the existence of allotropic modifications. He maintained that Acj, marked the absorption of heat due to the combination of iron and carbon to form the normal cementite FeaC. The intensity of the recalescence was proportional to the amount of FeaC formed and to the area of pearlite in the microstructure. Ara marked the faint evolution, and Aca the faint absorption, of heat due, respectively, to the passage of iron from a plastic to a crystalline condition and vice-versa. Aca marked the formation of a sub-carbide of iron. With regard to the At and As arrest-points, Professor Arnold contended that the so-called pure irons tested in various pyrometric laboratories had all contained a small proportion of carbon; he was, consequently, not satisfied with the Aj and Aa point obtained by the experimenters, as he considered that even a small percentage of carbon made its presence felt. His views changed somewhat with the passage of time, but for many years he steadfastly refused to believe that allotropy had anything to do with the A points, or with hardening by quenching.
Both Osmond’s and Arnold’s theories attracted a great deal of attention, and, throughout the world, active research was undertaken to prove or disprove statements brought forward by the two great pioneers. As fresh facts came to light, however, each hypothesis, as originally advanced, became much modified, and a gradual merging was accomplished. It is now generally accepted that hardening by quenching is partly due to allotropy and partly to carbon. Briefly summarised, a modern theory which has been fairly generally adopted, is essentially as follows :—The normal carbide held in solution at high temperatures (above Ars) by the gamma iron is, after quenching, apparently retained in solution in some form by the alpha iron finally produced.
As cementite is soluble to only a very slight extent in alpha iron in the ordinary way, the intense strain set up by such an abnormal state of affairs causes quenched steel to be hard and brittle. Opinions still vary, but animated discussions on the existence of beta iron are a thing of the past. On the other hand, no one to-day doubts that when iron is at a temperature above Au, it is allo-tropically different from the same iron in the alpha state below Acp or that such elements as manganese and nickel tend to maintain the iron in the gamma state even after slow cooling.
The one important thing to remember is that the controversy initiated by F. Osmond and J. O. Arnold gave a tremendous impetus to research and did much to place the science of metallography in the high position it now holds. Although the original question, i.e., the cause of hardening by quenching, has never been quite satisfactorily answered, the host of scientists engaged on this problem discovered many other highly important facts in the course of their experiments, thus adding much to our knowledge. In some respects, history repeated itself; the alchemists of old never found the eagerly sought - after philosopher’s stone, but their researches brought to light many unknown elements which proved of the greatest utility to mankind.
Professor Arnold was the author of papers of high practical value. His researches, in collaboration with Professor Bead, into the complex carbides occurring in chromium, vanadium, tungsten and molybdenum steels have gone far to increase the utility of these alloys. He was the first to describe the remarkable properties imparted to steel by introducing vanadium as a constituent. In 1919, he received a Carnegie scholarship award of 100?. towards the expenses of his high-speed steel researches carried out at Sheffield University.
All through his life, Professor Arnold seemed averse from having the names of individuals introduced into metallographic nomenclature, and, in a paper read in 1910, he “ pleaded earnestly with metallographists to abolish personal names for the constituents of steels.” He objected strongly to such terms as troostite, sorbite, martensite and austenite, and went so far as to state that their existence, as separate and distinct constituents, was extremely doubtful. He preferred to use such somewhat cumbersome expressions as “emulsified carbide,” “finely granulated carbide,” and “ diffused carbide.” He considered it unnecessary to. supplement Dr. Sorby’s original nomenclature. Very few metallographists followed his example, and the terms involving personal names, to which he so strongly objected, now stand for very definite and clear-cut constituents. The late Dr. J. E. Stead once said that if it had not been for Professor Arnold’s well-known aversion from such nomenclature he would have liked to suggest that vanadium steels should be termed “Amoldite” steels.
Professor Arnold was always an indefatigable supporter of the view that the chemical analysis of raw materials and finished products was an all-important point in the production of good steel, and he was. largely, responsible for the development of steel-works laboratories. In 1889, the laboratories attached to steel firms in Sheffield were in their infancy, and, in many cases, far too much reliance was placed on rough workshop tests. Professor Arnold, and his able assistants, set to work to adapt scientific methods of chemical analysis to the requirements of works practice. Rapid and accurate methods were devised, and the chemical laboratory gradually came to be regarded as an indispensable adjunct to the steel-making plant. Pieces of chemical apparatus bearing the professor’s name testify to his activities in this sphere. Arnold’s bulbs, for instance, for the absorption of carbonic-acid gas in the estimation of carbon in steel by combustion, are extensively used. Mechanical testing of materials also occupied his attention; the Arnold fatigue or vibratory test is well known. The difficulties experienced by steel-makers were naturally a matter of great interest to the Professor, and, when consulted, he was always ready and willing to give puzzled metallurgists the benefit of his knowledge and experience. Several papers read by him in the course of his career, the title of one of which was Forms in which Sulphides May Exist in Steel Ingots,” (in collaboration with G. R. Bolsover), showed that, while he delved deeply into the mysteries of theoretical metallurgy, his interest in current works practice remained keen.
It has sometimes been said that Professor Arnold did not pay enough attention to non-ferrous metallurgy, and that he might have devoted more time, than he actually did to the teaching of that subject. He was undoubtedly a “ steel man ” first and last, to the almost complete exclusion of all else. Possibly the worst criticism that can be levelled against Professor Arnold is that he was too dogmatic in his views and opinions. Be that as it may, we venture to state that he was no worse than other specialists. His conviction that his argument was the right one was always very strong, but in no case did he dispute another’s theory without bringing into play a large amount of scientific evidence. He will long be remembered by those who knew him, and he will go down to history as a most genial personality and a “ big man ” in every sense of the term. Professor Arnold is survived by his wife, two sons and a daughter, to whom the sympathy of all his friends will be extended."