Diary of John Quincy Adams, volume 2
This morning I received two very long Letters from my Mamma, and Sister;1 at length the whole mystery is revealed, and explain'd. We had from Mr. Williams a Lecture of an hour and an half, with which he finished the Subject of air.
One of these letters was AA to JQA, 16 Feb. (Adams Papers), in which he was informed of AA2's engagement. AA2's letter “No. 11,” which concluded on 15 Feb. and in which JQA learned on the first page “in the most delicate, manner possible... of the Connection,” has not been found (JQA to AA, 15–19 May, Adams Papers; JQA to AA2, 18 May – 17 June, AA2, Jour. and Corr., [3]:112–120).