Acoustical Society of America
Gold Medal Award - 1977

Raymond W. S. Stephens

IN AWARDING the Gold Medal to Raymond William Barrow Stephens the Acoustical Society of America confers its highest honour upon a distinguished scientist from overseas whose dedicated service and varied contributions to the field of acoustics have earned for him a special place in his own country and around the world.

Raymond Stephens was born in England at Tunbridge Wells, Kent on 13 October 1902 but spent most of his boyhood in Southfields, a suburb of London which is still his home. In his formative years he enjoyed the security provided by a quiet closely-knit family and the benefits of a classical education at Emanuel School, a public day school close to home. A keen interest in sports, which he shared with his two brothers and retains to this day, added an active dimension to his life.

In 1921, Stephens entered Imperial College, London where, after two years of study, he qualified as an Associate of the Royal College of Science. A year later he received his B.Sc. in Honours Physics from the University of London and was awarded the Remanet Research Studentship which enabled him to proceed to graduate studies. In 1925 he received the Diploma of Imperial College and was appointed Demonstrator, the first in a series of appointments in the Physics Department of Imperial College spanning a period of 45 years and culminating in his appointment as Reader in Acoustics in 1959. In the twenties the traditions of Callendar and Rankine still burned brightly at Imperial College so it was natural that Stephens should become interested in heat and the properties of matter. In 1934 his work with H.S. Gregory on the thermal conductivity of insulating materials earned for him a Ph.D. in Physics.

By 1947 Stephens was firmly established as a university teacher with strong interests in classical physics but this Acoustics Research Group had barely begun to take shape. This Group and all that has flowed from it is, perhaps, his greatest contribution to acoustics. Over a period of nearly 30 years, at Imperial and Chelsea Colleges, 83 graduate students prepared 97 theses and dissertations under his supervision. Of these, 59 were doctoral theses. His students, some from distant parts of the world, have, in their turn, contributed to the advancement of acoustics in at least a dozen countries. Fourteen or more, for example, are working in North America and several are active members of this Society.

It is perhaps Raymond Stephens' gentle style and warm personal interest in his students and associates which best accounts for the spectacular growth and success of his Acoustics Research Group rather than the attractions of the field itself. In the early days at least, since there was little central direction in the group, his students found opportunities for individual work sometimes lacking in the strongly organized teams working at the fashionable frontiers of physics. Stephens would mention rather than propose areas of research which his keen intuition sensed as promising and would then leave the students to read, think and define their problems for themselves. As their work progressed he would offer them scholarly guidance and tactful criticism rather than specific directions. In retrospect many would realize how wise his judgements had been. Material support for the students and the laboratory was sought and found in dozens of small corners of government and industry where the value of acoustics was recognized. Indeed, it was the practical value of acoustics which gained for the Acoustics Research Group a limited measure of support within the Imperial College Physics Department.

Visiting professors and other scientists from abroad soon came to appreciate the special opportunities for original work and personal development to be found in the Acoustics Research Group and many worked there for periods of several months or more. The informality of organization fostered a strong spirit of cooperation within the group. Visiting scientists, mature students and at times departmental staff (especially Geoffrey Parfitt) together with Stephens provided collegial leadership which made it possible for the Group to tackle a wide variety of problems simultaneously. With the benefit of hindsight it is easy to see how well Stephens shaped his Research Group. Under this guidance numerous areas of experimental physical acoustics were probed and developed; sound propagation in liquid metals, anisotropic solids, foams, plates, rods, and waveguides, finite amplitude waves in gases, liquids and solids, the optic-acoustic effect, viscoelasticity, sonoluminescence, ultrasonic attenuation at low temperatures, surface waves, modal regeneration, acoustic emission in stressed materials, and many others. The breadth of Stephens' interests is, indeed, a striking feature of his research career.

The great majority of Stephens' students thrived under his loose rein and many quickly became strong, resourceful and independent research workers. Students and visiting professors alike came to regard "Steve" with deep affection as the elder brother or father-figure in a world-wide family group. Paradoxically, the diffuse system which provided such valuable training for the students may also have delayed recognition for their teacher for it lacked the sharp focus on well-defined problems which is conducive to the building of personal reputations in research. Characteristically, Stephens was so modest about his own role that a dozen years passed before he felt able to accept personal credit in shared publications for any of the research performed under his supervision.

Stephens' contributions to the scientific literature are nevertheless considerable: author, co-author or editor of six books and more than fifty journal articles and book chapters. Sufficient has been said about his contributions to research but two of the books deserve special mention. His latest volume, Sound: Dictionary in Eight LanguagesAcoustics and Vibrational Physics published with A.E. Bate as coauthor in 1966 began as a second edition of Wave Motion and Sound but grew into something quite different. It is especially noteworthy for the series of 53 appendices which is really a collection of concise illuminating essays on a wide variety of topics such as radiation pressure, phonons, elasticity and viscosity, relaxation phenomena, and correlation techniques in acoustics. Many of these essays would be hard to match elsewhere.

Stephens' contributions to the organization of acoustics at home and abroad are many. Wherever he has seen a spark of creative activity he has tried to fan it into flame. In his own country, for example, the Acoustics Group of the Physical Society, the British Society of Audiology and the British Acoustical Society owe much to his efforts as founding member and officer. Most recently, the formation of the Institute of Acoustics, of which he was the first President, was the culmination of years of effort at bringing together sometimes divergent groups. Overseas, the Sociedad Española de Acustica and the Grupo de Acusticos Latino-Americanos, to mention two examples, benefited greatly at their inception from his encouragement and support. He was also one of the first to appreciate the benefits to be derived from a Federation of Acoustical Societies of Europe and has for many years been the English-language editor for the trilingual "Acustica". It is hardly surprising that he has been an invited lecturer at meetings in more than twenty countries.

During his academic career Raymond Stephens has found time for many professional activities outside his College. He is for example, recognized as a highly experienced examiner and has had major responsibilities for physics examinations within the University of London, in several professional societies, and in a number of universities in the developing countries. He was a part-time lecturer at several Colleges and Polytechnics in London especially at Chelsea College where he was Special Lecturer in Acoustics for twenty years and is now Research Fellow. For many years, he was Consultant in Acoustics to the Admiralty Underwater Establishment and Honorary Physicist at the Institute of Laryngology and Otology in London. Following his retirement from Imperial College in 1970, he spent a year as Visiting Professor at the University of Houston where he held a National Science Foundation Senior Foreign Scientist Fellowship.

Within the Imperial College Physics Department his administrative responsibilities brought him into close contact with the students. Indeed, because of his broad experience and his kind and sympathetic nature it was to him that students were most likely to turn in times of trouble. In 1959, his special role within the Department was recognized when the title of Senior Tutor was conferred upon him. It is surely no coincidence that, upon his retirement, the Imperial College Union (the student body) honoured him with its General Union Award presented to a member of staff on only one previous occasion.

There can be little doubt that Raymond Stephens is the "dean" of acoustics in his own country and that his contributions to the field place him in the front rank on the world scene. In the past few years the sterling qualities of this quiet, unselfish man have been recognized in the awarding of the Rayleigh Gold medal by the British Acoustical Society, the Silver Medal of le Groupement des Acousticiens de Langue Francaise in France, an honorary memberships in several acoustical societies including those in Spain and Latin America. Today, the Acoustical Society of America honours Raymond Stephens, a Fellow of the Society, for what he has done and wishes him well in the years ahead.

<\P> Edgar A. G. Shaw