1Horatio G. Spafford to Thomas Jefferson, 30 March 1814, with Postscript 7 April 1814 (Jefferson Papers)
inventions; of H. G. Spafford [index entry]
2Horatio G. Spafford to Thomas Jefferson, 24 April 1814 (Jefferson Papers)
inventions; of H. G. Spafford [index entry]
3Thomas Jefferson to Horatio G. Spafford, 26 April 1814 (Jefferson Papers)
inventions; of H. G. Spafford [index entry]
4Horatio G. Spafford to Thomas Jefferson, 23 January 1815 (Jefferson Papers)
inventions; of H. G. Spafford [index entry]
5Horatio G. Spafford to Thomas Jefferson, 28 January 1815 (Jefferson Papers)
inventions; of H. G. Spafford [index entry]
6Horatio G. Spafford to Thomas Jefferson, 15 February 1815 (Jefferson Papers)
inventions; of H. G. Spafford [index entry]
7Horatio G. Spafford to Thomas Jefferson, 18 February 1815 (Jefferson Papers)
inventions; of H. G. Spafford [index entry]
8Thomas Jefferson to Horatio G. Spafford, 21 February 1815 (Jefferson Papers)
inventions; of H. G. Spafford [index entry]
9Thomas Jefferson to Horatio G. Spafford, 15 March 1815 (Jefferson Papers)
inventions; of H. G. Spafford [index entry]
10Thomas Jefferson to Charles Willson Peale, 21 March 1815 (Jefferson Papers)
inventions; of H. G. Spafford [index entry]