(1869–1938).

Chemist and ceramist, director of the British Refractories Research Association.

Mellor was born on 9 July 1869 at Huddersfield, Yorkshire, England, and was the eldest son of Job Mellor, a power loom tuner, and of Emma, née Smith. He was brought to New Zealand by his parents in 1879. The family first settled in Kaiapoi, but moved soon afterwards to Dunedin, where the father worked at the Roslyn Woollen Mill. With no free secondary education available, Mellor, one of a family of six, left the Kaikorai School in 1882 and entered the bootmaking trade, working for most of the time with Sargoods. The lad did his best to satisfy his yearning for knowledge by evening study on his own, often in a tiny shed which he built for the purpose. Taking immediate advantage of the evening classes established at the technical school (later King Edward Technical College) in 1889, he matriculated three years later and entered the University of Otago as a part-time student. He completed his B.Sc. in 1897, winning the senior scholarship in chemistry. Twelve months later he took first-class honours and, as the preeminent science student of his year, was awarded the 1851 Science Exhibition Scholarship. Before taking up his scholarship at Manchester he served for a short time as lecturer in natural sciences at Lincoln Agricultural College. On 25 June 1899, at the Wesleyan Church, Mornington, Dunedin, Mellor married Emma Bakes, who was to be his constant companion and helper throughout his busy life.

With his unfettered opportunity for full-time research during the next three years, Mellor published a series of papers on the reaction between hydrogen and chlorine, wrote his first textbook, and gained the D.Sc. degree from the University of New Zealand.

It was a teaching appointment at the grammar school, Newcastle-under-Lyme, that first brought him into touch with the Staffordshire pottery industry. To Mellor the scope for scientific inquiry into its problems was clear. With characteristic versatility he was soon giving lectures to evening classes on ceramics, amongst other subjects. In 1905 he took charge of the County Pottery Laboratory, Tunstall, and became secretary and editor to the Ceramic Society. Though now devoting his energies largely to the service of industry, his academic reputation was such that in 1908 he was offered (but to the relief of his Staffordshire friends declined) the chair of chemistry in the University of Sydney. His continuing investigations covered a broad field, ranging from individual factory problems over such matters as the performance of fire bricks, the nature and behaviour of glazes, and the constituents of clays. During the First World War his chief work concerned the improvement of refractory linings of steelmaking furnaces. By 1920 almost a hundred papers, the majority over Mellor's name, had appeared from the Tunstall Laboratory. Thereafter this laboratory was merged within the British Refractories Research Association, where Mellor remained as director until his retirement in 1937, though pressing on at the same time with the writing of his monumental Comprehensive Treatise on Inorganic and Theoretical Chemistry. Mellor was elected a fellow of the Royal Society in 1927. He died in London on 28 May 1938.

For most men of science the task of directing a research organisation would be heavy enough. Yet in his spare time Mellor was writing varied academic texts culminating in the 16 volumes of the Comprehensive Treatise, totalling 15,000 pages, packed with fully referenced information abstracted directly from the world's chemical journals. Indeed, Mellor is best known in the scientific world for his writings on pure chemistry. These writings fall into three groups. To the first there belong Higher Mathematics for Students of Chemistry and Physics, 1902; Chemical Statics and Dynamics, 1904; and The Crystallisation of Iron and Steel, 1905. These are works in which the young author, writing as a research student and teacher, communicates an enthusiasm and clear understanding of specialised subjects. There followed a group of inorganic texts suited to under-graduate use: Treatise on Quantitative Chemical Analysis, 1912 (with a 1938 revision in collaboration with H. V. Thompson); and Modern Inorganic Chemistry, 1912, which ran to eight editions (totalling 154,000 copies) during Mellor's lifetime and has since continued under the editorship of G. D. Parkes. As independent abridgments of the latter there appeared Introduction to Modern Inorganic Chemistry, 1914; Intermediate Inorganic Chemistry, 1930; and Elementary Inorganic Chemistry, 1930. But there was need for a larger reference work in English on inorganic chemistry and, with the success of his earlier books, his publishers (Longmans) suggested such a text. Mellor had long been collecting and cataloguing material and, with so complete a coverage of the primary sources as he had attained, finally decided on a work no less than the Comprehensive Treatise. The first two volumes appeared in 1922 and the last in 1938 shortly before his death.

As a sharp contrast to his scientific writings we find Mellor's light-hearted wit breaking into print in Uncle Joe's Nonsense, 1934. This contains a collection of humorous stories illustrated with clever pen sketches, which Mellor (who had no family of his own) addressed to his nephews and nieces in New Zealand.

Mellor's early life provides a striking example of triumph over adversity and lack of opportunity. Without chance of secondary education he developed his literary ability and interest in science by reading such books as he could obtain. In his Dunedin years he seems to have made the most of limited social opportunity. He took his part in the activities of his church, eventually becoming a lay preacher, joined in a literary group, and became an excellent chess player. He was ready and determined to make the most of his belated opportunity for higher study. The kind of man to count his blessings, he remained mindful of his debt to the University of Otago, which set him on his way. So in his will he made the University a bequest for the furtherance of “Research in Pure Chemistry”. Mellor was quietly spoken and genial. He became all absorbed in whatever he was doing, whether it was research, writing, chess, or light-hearted amusement of the young.

Mellor subscribed to a wide range of chemical journals, his library growing to 15,000 books and 35,000 pamphlets. Reading French and German perfectly, and Italian and Russian adequately he kept up to date his card index of information for the Comprehensive Treatise with a minimum of clerical assistance. His literary style was fluent and picturesque, but is not seen to advantage throughout the greater part of the Comprehensive Treatise, which is so packed with factual material. His critical powers and sensitive response to the history and current state of his subject show up best in the introductory Vol. I. The appearance of succeeding volumes, almost yearly, evoked admiration and astonishment, tinged perhaps with apprehension as to whether the author could stay the course. Small wonder, because they comprise the greatest chemical work under single authorship in any language. The last two or three volumes were produced in the face of failing health, with Vol. XVI appearing just before the author's death. But Mellor was denied the opportunity to continue with a supplement he had planned to bring the earlier volumes up to date. Such a supplement is, however, now being produced. The first volume, 1956, is the cooperative effort of 23 authors working under an editorial board who resolved against rewriting the original on grounds both of the vast labour and the inevitable destruction of the style “so delightfully characteristic of the author”.

Mellor's achievements are the more remarkable through lying equally in the fields of pure and applied science, but this is the less surprising when viewed against other evidence of his versatility. It is difficult to escape the conclusion that Mellor's determination to undertake such heavy tasks must have been fortified through mastering the adversity of earlier years.

Both the Ceramic Society in England and the Wellington Branch of the New Zealand Institute of Chemistry have established annual memorial lectures in his honour. There is a commemorative plaque at Otago University, and Dunedin has named after him a park and a street in the Kaikorai Valley, where he spent his youth.

by Cuthbert John Wilkins, M.SC.(N.Z.), PH.D., D.I.C. (LOND.), Professor of Chemistry, University of Canterbury.

• Obituary Notices of Fellows of the Royal Society, Vol. II, 1936–38 (1939).