International Committee for Weights and Measures
His concern with measurement led to him becoming a member of the International Committee for Weights and Measures (CIPM) from 1907 - 1914. As president of the British Association for the Advancement of Science, he gave a presidential address in 1907 in which he advocated definitions based on fundamental physical properties, rather than on arbitrary standards such as a rod of metal with lines ruled upon it to mark the yard or metre.