Copy letter from William Bate Hardy, Secretary of the Royal Society; to [George William Clarkson] Kaye Esq., National Physics Laboratory, Teddington, Middlesex Replies to George William Clarkson Kaye that the set amount of free copies sent to the authors is 50 and that 2 authors are counted as 1. States that 50 is the practice and marked as head of the slip-proof in strict accordance with the practice. 6 March 1924