1Thomas Jefferson to John Quincy Adams, 10 May 1819 (Jefferson Papers)
An absence from home of some length has occasioned your letter of Apr. 24. to remain here unanswered until my return. the operation of sitting for portraits and busts, especially after it has been so often done, and probably as well as it will be done again, and that too before the havoc of age had left nothing but an anatomy to copy, needed the strong motive of my desire to meet any wish...