Charles Drummond Ellis

Sir Charles Drummond Ellis (11 August 1895 in Hampstead – 10 January 1980 in Cookham) was an English physicist and scientific administrator. His work on the magnetic spectrum of the beta-rays helped to develop a better understanding of nuclear structure.

Education and internment

Ellis was the son of Abraham Charles Ellis, a general manager of the Metropolitan Railway, and Isabelle Flockart Carswell. He won a scholarship to Harrow School where he excelled academically as well as at sport. In 1913, he became a cadet in the Royal Military Academy in preparation for a career in the Royal Engineers.

He was holidaying in Germany the following summer when World War I broke out. The camp had been a horse racecourse. During internment the detainees had a large degree of freedom. They had access to books, and Ellis made good use of his time to study. Another detainee in the camp was James Chadwick who was later to receive the Nobel Prize for his work on the discovery of the neutron. Chadwick inspired Ellis and together they erected a laboratory in one of the horse stables where they undertook scientific experiments on the photochemical process.

Career after the war

After the war Ellis decided to abandon a military career. He entered Trinity College, Cambridge where he studied natural sciences. After graduating in 1920 he became engaged in research work at the Cavendish Laboratory, Cambridge, where the director, Sir Ernest Rutherford, had now engaged Chadwick. While Rutherford and Chadwick worked on alpha radioactivity and alpha particles for nuclear disintegration experiments Ellis studied beta and gamma radiation. He became a leading authority on the subject, publishing many articles in scientific journals.

In 1921 Ellis had become a fellow of Trinity College and was appointed assistant lecturer in natural science. In 1925 he married Paula Warzcewska, the daughter of a wealthy Polish shipbuilder. Although there were no children Paula (known as Polly in England) had a daughter from a previous marriage. In 1929 he was elected a fellow of the Royal Society.

Discovery of the neutrino During the early 1930s Ellis worked with Nevill Mott on energy relations in beta decay. Mott said later that Ellis had “practically discovered the neutrino”. He worked with W.J. Henderson on the energy distribution of positrons in artificial radioactivity. In 1936 Ellis was elected a fellow of the American Physical Society.

In 1936, a year after Chadwick's appointment to a professorship at Liverpool, Ellis was appointed to the Wheatstone chair of physics at King's College London in succession to Edward Victor Appleton who had become professor of natural sciences at Cambridge.

Later career After World War II Ellis held several posts which were not related to nuclear weapons. He was director of the Finance Corporation for Industry, in charge of research and development for the National Coal Board. He was president of the British Coal Utilization Research Association from 1946 to 1955 and a member of the advisory council to the minister of fuel and power from 1947 to 1955. He retired from the Gas Council in 1966 and from BAT in 1972.

During his final decade his health was poor. In 1980 he died in a nursing home in Cookham after a short illness. performed an important experiment with β-rays. Their experiment led to Pauli's suggestion of the neutrino.