Copy letter from Robert William Frederick Harrison [signed by A H White] to Wilfrid Short, 4 Carlton Gardens, SW 'In answer to your enquiry I find the following reference:- R C Tolman: The Second Postulate of Relativity. Physical Review (New York) for July 1910. That paper contains references to another by Lewis Tolman: Phil Mag, 1909, October. There may be other papers to be found by further hunting. Would you care to come in next week and turn over some of the periodicals?' 5th August 1911