Charles Rundle Davidson, 1875-1970

Abstract Charles Rundle Davidson was born on 28 February 1875 and educated at Christ’s Hospital. He joined the staff of the Royal Observatory, which was then at Greenwich, on 10 March 1890, and was established as a Computer on 1 June 1896. He spent the whole of his working life at the Royal Observatory and retired on 31 August 1937, after more than 41 years’ established service. He died on 18 June 1970. When Davidson joined the staff of the Royal Observatory it was sharply divided into senior and junior ranks, and Davidson was a junior. Nevertheless he established a reputation for ability to handle equipment which was so great as to elevate him to the recognized position of the Observatory’s arbiter on all instrumental matters, and Dyson in particular relied on Davidson absolutely to supervise the later eclipse expeditions which Dyson made such a feature of the work of the Royal Observatory. In all, Davidson went on eight eclipse expeditions, of which the most famous was the eclipse of 1919, at which the Einstein effect, that is to say the deflexion of starlight passing the limb of the Sun, was first found. The whole matter was extremely important in establishing the relativity theory, and the expeditions of 1919, of which there were two from Greenwich, were given great prominence in Eddington’s writings. Eddington and Cottingham went to the island of Principe off the coast of Africa, and Davidson and Crommelin went to Sobral in North Brazil. At Principe the sky was partly clouded but some star images were found on the plates. At Sobral the observers were favoured with fine weather.