Evan James Williams was born on 8 June 1903 at Brynawel, Cwmsychbant, Cardiganshire, the youngest of three sons born to James Williams (1868-1950), stonemason, and his wife Elizabeth (Bes) (née Lloyd, 1870-1948). He was known amongst his friends by the nickname 'Desin' because of his proficiency with decimal numbers.
He attended Llanwenog School and Llandysul County School before winning a scholarship at the age of 16 to Swansea Technical College, subsequently transferring to University College Swansea when that establishment opened in October 1920. In 1923 he was awarded a first-class degree in physics and in the opinion of the external examiner, Professor Charles Barkla, a Nobel prize winner, 'his papers submitted in the Honours Degree Examination were some of the most remarkable I have ever had the privilege of reading'.
He stayed at Swansea for another year to study the electrical conductivity of liquid metals, leading to the award of an MSc. He then moved to the physics department at the University of Manchester, where, for his doctorate, he investigated the scattering of X rays by various gases. With the support of a University of Wales fellowship he succeeded in completing his thesis and was awarded a PhD at the end of 1926. It is striking that his supervisor confirmed that the theoretical aspects of the work had been completed without any assistance from others.
In 1927 he secured an 1851 Royal Exhibition scholarship to study at the Cavendish laboratory, Cambridge University, where he became a member of Gonville and Caius college. Under the supervision of the head of the laboratory, Ernest Rutherford - one of the giants of 20th-century physics - Williams studied collisions arising from the motion of fast electrons through gases. He was awarded a second doctorate at the end of 1929.
By then Williams had published several papers, including some in the Proceedings of the Royal Society, and the head of the University of Manchester physics department, Laurence Bragg, was anxious to attract him back to the department. He was appointed assistant lecturer at Manchester at the end of 1929. A few months later, in 1930, he was awarded the degree of DSc by the University of Wales on the basis of his publications. In 1931 he was promoted to a special position as lecturer in mathematical physics.
Williams continued to study atomic collisions and published five theoretical papers in the Proceedings of the Royal Society. In these papers his analysis of collisions was based on the new physics - quantum physics - that over the previous two decades had transformed scientists' understanding of the atom. He also incorporated classical concepts which provided a clearer insight into the nature of the collisions than that provided by the complex mathematics of quantum physics. This was welcomed by those not fully conversant with the new physics.
As well as pursuing his own research Williams was also more than willing to assist fellow academics in developing theoretical models pertaining to their respective research areas. A notable example was the development of the Bragg-Williams model to explain the results obtained when cooling hot alloys. Subsequently this work became well known amongst chemists. Williams succeeded in completing his solution by working throughout the night and presenting the analysis to the head of department the following morning!
In 1933 Williams secured a Rockefeller fellowship which allowed him to work during the 1933-34 academic year with Niels Bohr at his institute in Copenhagen. This was quite a feather in his cap since Bohr was one of the leading founders of quantum physics and an authority in the field. Consequently the institute attracted physicists from far and wide - a wonderful opportunity for Williams to discuss and exchange ideas with some of the most able thinkers in atomic physics.
The year spent in Copenhagen proved to be very fruitful for Williams. One outcome was the development of a theoretical method for analysing atomic collisions that could be applied to a wide range of situations. In due course it became well-known as the Weizäcker-Williams method and was widely adopted and is still used today. The German Carl von Weizäcker is named because, independently, he extended Williams's analysis.
Another study carried out jointly by Williams and Bohr led to a far-reaching result. It was stimulated by a disagreement amongst physicists about the nature of cosmic rays from space with some suggesting that extremely energetic particles did not behave in accordance with the laws of quantum physics. Williams and Bohr succeeded in disproving this, and their analysis suggested further that a previously unknown particle existed.
After returning from Copenhagen Williams spent another two years at Manchester before being appointed lecturer and Leverhume fellow at the physics department, University of Liverpool in 1936 under the head of department James Chadwick. By now Williams's atomic physics research was recognised internationally and his presence was a significant asset raising the department's research profile. Additionally, Chadwick had similar research interests having received a Nobel prize for discovering the neutron (the proton's 'partner' in the atomic nucleus). He encouraged Williams to look for the unknown particle that had been predicted in Copenhagen and equipment was built for the study of cosmic rays, where the particle was most likely to be found. One year later, in 1938 Williams was amongst the few physicists who succeeded in obtaining evidence of the existence of the particle - the meson as it was subsequently called.
Williams spent two years at Liverpool before being appointed, in 1938, to the chair of physics at the University College of Wales, Aberystwyth; a promotion which gave him the opportunity to be near to his parents and his native haunts which were so close to his heart.
With the growth in interest in the meson it is not surprising that Williams brought the apparatus which he had built in Liverpool to Aberystwyth. At the end of 1939, he succeeded in recording the decay of the meson. He was the first person to demonstrate the event thus placing Aberystwyth at the forefront of meson studies.
Meanwhile Williams's status received further recognition in 1939 when he was elected Fellow of The Royal Society. He was also invited, in the same year, to present a series of lectures at the University of Michigan's theoretical physics summer school, an event described as a 'summer school for geniuses'.
With the success of his work on the meson there was every reason to believe that subsequent years would bring international recognition to Aberystwyth. However, the outbreak of the Second World War cut across the work of the department and it became necessary to concentrate on supporting the war effort. Williams joined a group of scientists who were tasked with developing statistically based strategies for attacking German submarines in the Atlantic. It is judged that the analyses carried out were indispensable in targeting the submarines and thus protecting convoys transporting essential goods to Britain. Williams became leader of the group and his ability in developing the requisite statistical techniques was regarded as without equal.
At the end of the war it was Williams's intention to recommence his study of the meson. However, he developed bowel cancer and despite surgery did not recover, and he decided to return home to his parents in Cwmsychbant where he died on 29 September 1945. He was buried in the cemetery of Capel y Cwm, Cwmsychbant.
He was described by the Nobel prize winner, Patrick Blackett, as 'one of the most brilliant physicists of our generation'. There is no doubt that Williams had reached the peak of his profession and his contribution to atomic physics was recognised throughout the world. With much more to be achieved, his early death at the height of his powers was a huge loss to physics and to Wales.
Published date: 2022-07-28
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Born 8 June 1903 at Cwmsychpant, Cardiganshire, the son of James Williams, mason and Elizabeth (née Lloyd), his wife. He proceeded from the primary school at Llanwenog to the county school at Llandysul, and from there to the University College of Swansea, where he took a first-class honours degree in physics in 1923. He pursued scientific researches at Swansea, Manchester and Cambridge, and had obtained the degrees of Ph.D. (Manc.), Ph.D. (Cantab.) and D.Sc. (Wales) by 1930. Between 1929 and 1938 he was lecturer successively at the Universities of Manchester and Liverpool, and he was for a session (1933-34) at the University of Copenhagen. In 1938 he was appointed to the chair of physics at Aberystwyth, but his career there was interrupted by the outbreak of war, and from 1939 to 1945 he was engaged in scientific research in connection with the armed forces. He was elected F.R.S. in 1939. He was a scientific officer at the Royal Air Force establishment at Farnborough, 1939-41, director of research for the R.A.F. Coastal Command, 1941-42, scientific adviser to the Navy on methods of combating submarines, 1943-44, and assistant director of research in the Navy, 1944-45.
He died 29 September 1945. A list of his publications and an appreciation of his work as a scientist and of the significant part which he played in the battle against submarines are given by P.M.S. Blackett in Obituary Notices of Fellows of the Royal Society, vol 5, No. 15, 1947.
Published date: 2001
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