Draft letter, from Sir John Herschel to George Robert Waterhouse, dated at Collingwood Autographed draft letter. Thanks for answers and for notice on Apteryx [Maerurus ?], which John Frederick William Herschel remembers watching Richard Owen inspect. Interested in W. B. Carpenter's and C. W. Thomson's ['Bathybius?]' as origin of chalk-flint. Discusses inorganic chemical allotropes. Organic allotropes may exist, serving as 'agents of vital action' and subject to a higher power. 1 April 1869