Obituaries:Professor Mansel Davies

Mansel Davies was a scientist of the highest quality, a formidable historian and philosopher of science, a brilliantly effective teacher of undergraduates and supervisor of research students, a passionate crusader for social and political justice, a lifelong militant pacifist, a Pugwash participant, a committed humanist with strong leanings towards Buddhism, a prolific author and letter writer, a discriminating collector, a riveting anecdotalist, a man of omnivorous literary, musical and scientif ic tastes.

He was also blessed with the gift of friendship. A classless democrat always true to himself, he mingled as freely with US presidential and British prime-ministerial advisers as he did with the farmers, railway workers and shop assistants of Dyfed and Gwynedd. Likewise, he befriended and advised artists, politicians, preachers, broadcasters, lawyers, professors and heads of Oxford and Cambridge houses, many of whom are profoundly in his debt. Little children adored him: he was their favourite uncle or grandfather.

Davies's scientific reputation was made in six interconnected areas, all centred on the intricacies of molecular behaviour: the development of high- resolution, infra-red spectroscopy (1938-65); the elucidation of the nature of hydrogen bond by infra-redand other spectroscopic probes (1938-60); the lattice energies of molecular crystals (1954-65); the introduction of dielectric loss and relaxation as a means of probing molecular behaviour (1954-75); and pioneering the development, with the late John Chamberlain of the National Physical Laboratory, of Fourier-transform infra-red spectroscopy (1968-77). He also authored a number of influential books, the first, An Outline of the Development of Science (1947), in response to an invitation by H.G. Wells to contribute to the Thinkers Library. This was, in extended form, translated into Welsh with his wife Rhiannon in 1948 (as Hanes a Datblygiad Gwynddoniaeth), and into other languages. In 1949 he published a monograph, The Physical Principles of Gas Lique- faction, which arose from a brief adventurous spell in industry before the Second World War.

Davies was born in 1913, in the mining town of Aberdare in South Wales. Educated in the grammar school there he proceeded with a scholarship to the University College of Wales, Aberystwyth, in 1930. There he was greatly influenced by a remarkable lecturer in chemistry, C. R. Bury. Bury imbued Davies with a passion for hard work and an eye for the elegant experiment.

After completing a Masters degree in Aberystwyth, Davies went to Cambridge on a University of Wales Fellowship. Later he became G.B.B.M. (later Sir Gordon) Sutherland's first research student in infra-red spectroscopy. While in Cambridge he rubbed shoulders with his fellow South Walian W.C. (Bill) Price, later Wheatstone Professor of Physics, at London University, and, among others, Wu Zheng Kai, now the doyen of physical chemists in the People's Republic of China. (The three of them met again in Faraday's laboratory at the Royal Institution in 1988, after Kai had been ``lost'' in the Cultural Revolution and rehabilitated.)

Being a conscientious objector, Davies declined to do war work: in 1940 he started as physics and chemistry master in Bethesda Grammar School, North Wales (Ysgol Dyffryn Ogwen). While there he began his comprehensive investigations into the nature of thehydrogen bond, which is responsible for the cohesion of polar (and especially of biologically and pharmaceutically significant) molecules. In 1942 he married the French mistress, Rhiannon Williams, of Wallasey, also an ex-Aberystwyth student. In 1942 hemoved to Leeds University, where he became research assistant to W. T. Astbury, who had just become the world's first professor of biomolecular structure. Astbury's seminal work on cellulose and fibrous proteins (constituents of skin and hair) appealed to Davies, who soon acquired the skills of X-ray crystallography - he was one of the first to record the now familiar X-ray diffraction pattern of DNA - and who could see how vitally important the hydrogen bond is in biology. Davies's influential review of the hydrogen bond, published in the Annual Report of the Chemical Society in 1946, became essential reading for generations of students and researchers.

From 1946 to 1947 Davies held an ICI Fellowship at Leeds; but in 1947 he returned as lecturer to his Alma Mater, where he remained, apart from sabbatical periods, for the rest of his prodigiously active working life.

At Aberystwyth his research collaborators came from every corner of the globe. And he exported numerous top-quality research workers to the leading universities of the world and to many industrial and government research laboratories. He also collaborated with manufacturing industries, notably the Grubb Parson Co, in the commercialisation of infra-red instruments. The Edward Davies Chemical Laboratory, Aberystwyth, was in his day as cosmopolitan as any I have known. The late George Pimentel, of Berkeley, California, a leading US scientist and close friend of Davies's, once began a lecture at Aberystwyth after an eight-hour train ride (with four changes) from London with the remark that he had crossed difficult Indian country to get to his destination.

Davies's research at Aberystwyth entailed extension of his earlier infra-red work to retrieve quantitative information on dimer formation of carboxylic acids, amides, alcohols and amino acids. But more significantly, he initiated in Britain, simultaneou s ly with the late L.E. Sutton, of Oxford, the technique of dielectric loss spectroscopy that C.P. Smyth, at Princeton, and R.H. Cole of Brown University had earlier begun to deploy. Davies had been much influenced by the great Dutch chemist Peter Debye,w ho was awarded the 1936 Nobel Prize for his investigations of the dipole moments of polar molecules. Davies exploited such insights with imaginative flair and discrimination.

A long succession of original papers emerged, and he published three other substantial texts: Infra Red Spectroscopy and Molecular Structure (1963), which earned praise from the Nobel laureate Hertzberg; his paperback Some Electronic and Optical Aspects of Molecular Behaviour (1965), which became a classic; and with three colleagues (A.H. Price, N. Hill and W.E. Vaughan) he produced in 1969 Dielectric Properties and Molecular Processes. Davies's work on lattice energies entailed measuring the vapour pressures of many families of organic compounds. These yielded valuable insights into the strength of molecular interaction in the crystallising state, information that X-ray crystallography cannot provide. He also edited (1970-73) volumes 1

t o 3 of the Royal Society of Chemistry's specialist periodical reports on Dielectric and Related Molecular Processes. There was widespread disappointment that he was not made Professor and the Head of Department of Chemistry at Aberystwyth in 1960. But a personal chair was created for him there in 1968.

Mansel Davies's circle of friends was enormous. He had an engaging personality, a natural kindness and genuine warmth. All this coupled with a Renaissance face with its serene charm made him a most attractive character. But he was also an original thinker, a man of action and of infectious enthusiasms. He described in semi-popular articles and letters to friends his conversations with Bertrand Russell, Michael Polanyi, Margaret Thatcher, Peter Debye, and Hans Bethe. In his retirement he intensified his interest in Oriental religions, in the science and technology of ancient China, the latter through his close friendship (for over 20 years) with Joseph Needham, whose selected writings formed the subject of one of the three books Davies completed after the age of 75. The others were: A Scientist Looks at Buddhism (1990), that led to his being invited in 1993 to Paris to address an audience of ambassadors on Theravada Buddhism; and A History of the Faraday Society, which is

to be published by the Royal Society of Chemistry. In his retirement he gave tangible support to the Llangollen Inter- national Eistedfodd, amalgamating his love of music and international friendship.

Mansel was a man of extraordinary vitality. If style is defined as doing things in memorable ways, he certainly had style. Those who knew him will never forget him.

His wife Rhiannon, an accomplished linguist, poet and harpist, died in 1988. He is survived by his two sons, Huw Ceredig, principal percussionist of the Birmingham Symphony Orchestra and Rhodri Ceredig, a molecular biologist in the University of Strasbourg.

John Meurig Thomas

Mansel Morris Davies, physical chemist: born Aberdare 24 March 1913; Research Assistant and ICI Fellow, Leeds University 1942-47; Lecturer, Senior Lecturer, Reader, Professor of Chemistry, UCW Aberystwyth 1947-77; married Rhiannon Williams (died 1988; two sons); died Criccieth 11 January 1995.