The year is established by the relationship between this letter and the letter from A. H. Sayce, 2 August 1877.

Whitney’s letter has not been found. The newspaper abstract that was forwarded to Archibald Henry Sayce has not been identified, but was evidently a report relating to the 10 to 12 July 1877 meeting of the American Philological Association in Baltimore (for a full report of the meeting, see Transactions of the American Philological Association 8 (1877): 3–39). After reading CD’s article ‘Biographical sketch of an infant’, Sayce had written to CD to ask for information on sounds made by infants (see letter from A. H. Sayce, 27 July 1877, and letter to A. H. Sayce, 28 July 1877). Two papers read at the Baltimore meeting concerned language acquisition in children (Holden 1877 and Whitney 1877).

Whitney’s paper ‘The principle of economy as a phonetic force’ later appeared in Transactions of the American Philological Association (Whitney 1877), but no copy has been found in the Darwin Archive–CUL.

CD’s article, ‘Biographical sketch of an infant’, had appeared in the July 1877 issue of the journal Mind: a Quarterly Review of Psychology and Philosophy. The article was based on notes CD had made on his children’s development from the birth of his first child, William Erasmus, in December 1839; the notebook is in DAR 210.11: 37.

The message has not been found, but was probably for George Howard Darwin. George had published an article titled ‘Professor Whitney on the origin of language’ in the Contemporary Review (G. H. Darwin 1874).