11Peter S. Du Ponceau to Thomas Jefferson, 6 January 1818 (Jefferson Papers)
language; Indian (American) [index entry]
12Peter S. Du Ponceau to Thomas Jefferson, 22 January 1818 (Jefferson Papers)
language; Indian (American) [index entry]
13Enclosure: Nicholas Biddle to William Tilghman, 6 April 1818 (Jefferson Papers)
language; Indian (American) [index entry]
14Peter S. Du Ponceau to Thomas Jefferson, 14 April 1818 (Jefferson Papers)
language; Indian (American) [index entry]
15Enclosure: Prospectus for Transactions of the Historical and Literary Committee of the American Philosophical Society … (Jefferson Papers)
language; Indian (American) [index entry]
16Thomas Jefferson to Peter S. Du Ponceau, 14 March [1819] (Jefferson Papers)
language; Indian (American) [index entry]
17Enclosure: Edy Turner’s Vocabulary of the Nottoway Language, 4 March 1820 (Jefferson Papers)
language; Indian (American) [index entry]
18Thomas Jefferson to Peter S. Du Ponceau, 7 July 1820 (Jefferson Papers)
language; Indian (American) [index entry]
19Peter S. Du Ponceau to Thomas Jefferson, 12 July 1820 (Jefferson Papers)
language; Indian (American) [index entry]
20Enclosure: Peter S. Du Ponceau’s Comparison of Indian Numerals, [ca. 12 July 1820] (Jefferson Papers)
language; Indian (American) [index entry]