1Charles Willson Peale to Thomas Jefferson, 19 August 1812 (Jefferson Papers)
agriculture; threshing machines [index entry]
2Charles Willson Peale to Thomas Jefferson, 28 December 1813 (Jefferson Papers)
agriculture; threshing machines [index entry]
3Charles Willson Peale to Thomas Jefferson, 2 May 1815 (Jefferson Papers)
agriculture; threshing machines [index entry]