The year is conjectured from the date range of the accession of volume 5 of Mueller 1858–82 recorded by the library of the Linnean Society of London (see n. 2, below).

The reference is to Mueller 1858–82. The work consists of twelve volumes, two of which (vols. 1 and 5) were dedicated to CD by the author. CD’s copy of volume 5 had been sent by Ferdinand von Mueller in care of Joseph Dalton Hooker (see Correspondence vol. 16, letter from J. D. Hooker, 25 July 1868 and n. 3). CD’s gift of vol. 5 to the Linnean Society was recorded in Proceedings of the Linnean Society of London, ‘Additions to the library of the Linnean Society’, 4 June 1868 – 15 June 1869, p. xix. CD probably sent the library his copy of vol. 1 at the same time, but the library had already received that volume in parts between 1858/9 and 1862/3. It is likely that CD wrote this letter in reply to a request from Kippist to keep CD’s copy of vol. 1 for his personal collection. The letter was found at the Linnean Society library, tipped into CD’s copy of vol. 1, which was stamped ‘Linnean Society of London 29 Sept. 1943’.