Thomas Jefferson to Jacob Bigelow, 11 April 1818Enclosure: Thomas Jefferson’s Summary of Weather Observations, 1810–1816, [ca. 11 April 1818]Thomas Jefferson to Nathaniel Bowditch, 11 April 1818Mathew Carey & Son to Thomas Jefferson, 11 April 1818Thomas Jefferson to Thomas Cooper, 11 April 1818Destutt de Tracy to Thomas Jefferson, 11 April 1818Thomas Jefferson to James Madison, 11 April 1818Thomas Jefferson to Benjamin Silliman, 11 April 1818Enclosure: Nicholas Biddle to William Tilghman, 6 April 1818 