December 16, 1800 | Letter Thomas Jefferson to Caspar Wistar, December 16, 1800 In a personal addition to his other letter of December 16, 1800, Thomas Jefferson assures Caspar Wistar of William Dunbar's fitness for membership in the American Philosophical Society.
April 18, 1802 | Letter Thomas Jefferson to Robert Livingston, April 18, 1802 Thomas Jefferson sends a cipher to Robert Livingston, as well as his musings on the cession of Louisiana.