1Thomas Jefferson to Nathaniel Bowditch, 11 April 1818 (Jefferson Papers)
astronomy; TJ on [index entry]
2Thomas Jefferson to Francis Adrian Van der Kemp, 9 February 1818 (Jefferson Papers)
astronomy; TJ on [index entry]
3Thomas Jefferson to Wilson Cary Nicholas, 19 April 1816 (Jefferson Papers)
astronomy; TJ on [index entry]
4Thomas Jefferson to Robert Patterson, 21 March 1811 (Jefferson Papers)
astronomy; TJ on [index entry]