In 1920 he resigned the chair in Poitiers which he had held since 1908 and accepted a chair in the history of science at the Collège de France.
Sa 1920 niya ang kalooban ng upuan sa Poitiers kung saan siya ay gaganapin mula noong 1908 at tinanggap ng isang upuan sa kasaysayan ng agham at ang College de France.