Charles Drummond Ellis (1895-10.01.1980) was an English physicist and a Fellow of the Royal Society. He was born in London. He graduated from the Military Academy in Woolwich and the University of Cambridge, and worked at the Cavendish Laboratory. In 1936—46 he was professor at the University of London, and in 1945 — 65 director of the Finance Corporation for Industry.
His scientific work concerned atomic physics, radioactivity and the photoelectric effect. Together with W. Wooster he carried out (1927) measurements of the mean energy of the electrons in beta decay (the Ellis — Wooster experiments). He measured the velocities of photoelectrons ejected under the action of high-frequency radiation and confirmed Einstein's law of the photoelectric effect in the region of high frequencies (for visible and ultraviolet rays its validity was proved by R. Millikan).