Correspondence on the Royal Society's radium source Letters concerning the use of the Royal Society's store of radium. The specimen, around 46-50 milligrams of radium chloride, was in the care of Frederick Alexander Lindemann at the Clarendon Laboratory, Oxford, from 1926. It was then transferred for the use of James Chadwick at the George Holt Physics Laboratory, University of Liverpool, in 1935. It was transported to Sir George Thomson at Imperial College London in 1949. The liquid sample was eventually dehydrated and sealed in 1953. This file contains the background correspondence between the Royal Society's officers and Lindemann, Chadwick, Samuel Devons and others. 1935-1953