Began his work at the University of Manchester, 1934-47, as an Assistant Lecturer, later Senior Lecturer and Reader, under Professor William Lawrence Bragg. From 1947-1973 he was Professor of Physics at Royal
Holloway College. He supported the admission of male undergraduates to what was founded as a women's only College to strengthen the research.
He was elected as a fellow of the Royal Astronomical Society, 1947 and to the Royal Society in 1952. He was awarded the C. V. Boys prize for contributions to optics by the Physical Society of London in 1948 and a Silver Medalist, Royal Society of Arts in 1961.
One area in which he was very interested was the optics of diamonds; this brought him to analyse optical characteristics of moon-dust from the Apollo 11 mission. A lunar crater was named after him in recognition of his work in NASA's Apollo program.
His teaching career started in 1906 following his return from Germany, where he graduated, as assistant lecturer in Wheatstone laboratory in King's College, London. During the years spent at King's College, he developed his work and knowledge on the emission of photons from hot bodies. He also continued being interested in the theory of relativity and quantum theory.
Thanks to his knowledge of generalised mechanics, he was able to appreciate the consequences of the postulates introduced by Niels Bohr in the quantum theory field.
In 1915 this culminated in the discovery of the condition . He also explained the atomic orbits of the electrons and derived the formula for the eccentricity of an elleptic orbit.
In 1919 he was appointed to a readership at the Physics Department in King's College, while in 1921 he was appointed to the Hildred Carlile chair of physics at Bedford College where he ended his career in 1944.