11Thomas Jefferson to Alexander Hepburn, 20 May 1820 (Jefferson Papers)
agriculture; threshing machines [index entry]
12Thomas Jefferson to Charles Willson Peale, 21 March 1815 (Jefferson Papers)
agriculture; threshing machines [index entry]
13Alexander Hepburn’s List of Materials for Work at Poplar Forest [ca. 8 October 1819] (Jefferson Papers)
agriculture; threshing machines [index entry]
14Cunningham Harris to Thomas Jefferson, 30 September 1812 (Jefferson Papers)
agriculture; threshing machines [index entry]
15Thomas Jefferson’s Calculation of Timber Needed by Alexander Hepburn at Poplar Forest, [ca. 8 October 1819] (Jefferson Papers)
agriculture; threshing machines [index entry]
16Thomas Jefferson to Charles A. Scott, 9 February 1811 (Jefferson Papers)
agriculture; threshing machines [index entry]
17Joel Yancey to Thomas Jefferson, 8 October 1819 (Jefferson Papers)
agriculture; threshing machines [index entry]
18Thomas Jefferson to Benjamin B. Ford, 28 November 1809 (Jefferson Papers)
agriculture; threshing machines [index entry]
19Joel Yancey to Thomas Jefferson, 14 October 1819 (Jefferson Papers)
agriculture; threshing machines [index entry]
20Benjamin B. Ford to Thomas Jefferson, 17 November 1809 (Jefferson Papers)
agriculture; threshing machines [index entry]