Copy letter, from Sir John Herschel to Sir Charles Lyell, dated at Collingwood Copy of draft letter in John Herschel's hand. Received some proof sheets this morning of the Appendix to Charles Lyell's book on the Antiquity of Man. Has read through the book with great interest. Comments on various points. Will have to revise their ideas on the length of human existence. Has had another letter from Twisleton so supposes he must try and write on science in schools. Have had sickness for the first three months of the year. 13 April 1863