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. (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). (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. (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.

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. There he was greatly influenced by a remarkable lecturer in chemistry, C R Bury. Educated in the grammar school there he proceeded with a scholarship to the University College of Wales, Aberystwyth, in 1930. 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. This was, in extended form, translated into Welsh with his wife Rhiannon in 1948 (as Hanes a Datblygiad Gwynddoniaeth), and into other languages.

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. 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). 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. 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.

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. "I suppose some people would regard it as ironic," he admits.Two Armani-suited Saatchi executives were leaving Charlotte street for their prandials yesterday. "Will you be back after lunch?" a colleague shouted after them "We'll see what they offer," came the gallows humour reply.. NatWest may be wondering about its employee's role in the affair."I did not formulate that policy, but did provide background information," said an embarrassed Fanning, 37. He helped devise Labour's slick response to the Budget. The campaign of love hit a nasty bump last week when comments by Gordon Brown were interpreted as an attack on excessive bank charges Fears of a banking levy arose. The capital markets guru, who was secretary of the Birmingham University Labour Party and who is seeking a seat in Parliament, has been quietly working with Chris Smith, Treasury spokesman, on planning Labour's seduction of the City. NatWest may be cursing the day it gave Peter Fanning leave of absence for a year to work at the Labour Party's Westminster Treasury team.