The date range and the addressee are conjectured from the existence of other letters mentioning spermaceti to William Baxter or his son, William Walmisley Baxter, who were chemists in Bromley, Kent, close to Down, where CD lived from 1842 (see n. 2, below, and this supplement, letter to [William Baxter or W. W. Baxter?], 8 December [1842–81].

Spermaceti ointment was used as a mild dressing for blisters, cuts, and grazes (Warren 1859, p. 675); CD also used it in his botanical work (see Correspondence vol. 26, letter to W. W. Baxter, 6 January [1878] and n. 2). It contained five ounces of spermaceti to two ounces of white wax and twenty ounces of almond oil (ibid., letter from W. W. Baxter, 7 January 1878).