George Young visited CD and had lunch at Down House on 8 May 1875 (see letter to J. B. Innes, 10 May [1875]); presumably he was accompanied by Alfred Tylor. Young served as lord advocate of Scotland from 1869 to 1874; he established a national system of publicly funded compulsory elementary education in Scotland with the passing of the Education (Scotland) Act in 1872 (ODNB).

This letter has not been found.

At a meeting of the Geological Society of London in 1852, Alfred Tylor had first expounded his theory that sea-level changes and denudation required a sustained period of increased rainfall (a pluvial period); opposition to his views resulted in the removal of any reference to a pluvial period from the abstract published in the Quarterly Journal of the Geological Society of London (Tylor 1852), but his views appeared in full in the version of his paper published in the Philosophical Magazine (Tylor 1853). Tylor again encountered opposition to his views at the Geological Society in 1868 when he explained post-glacial river-gravel deposits in terms of his pluvial theory (Tylor 1867, 1868a, 1868b, 1868c), and further argued that the erosion of valleys was more rapid when they had large, swiftly moving rivers flowing through them as a consequence of higher than normal rainfall. By 1872, other geologists had begun to argue that rainfall in the post-glacial period must have been heavier than in modern times (see Correspondence vol. 20, letter from Alfred Tylor, 8 June 1872 and n. 3), and Tylor published a full version of his paper on the formation of deltas (which had appeared only as an abstract in 1868 (Tylor 1868c)), together with an appendix outlining his view of the disputes surrounding it (Tylor 1872).