Copy of draft letter, from Sir John Herschel to William Ritchie, dated at London Copy of draft letter, copied as part of the correspondence project led by Colonel John Herschel FRS following the death of his father. Presented William Ritchie's paper on a new photometer to Royal Society [of London] Discusses how objections may be avoided. Believes [John] Leslie's photometer should be thrown aside. 27 January 1825