March 2, 1803 | Letter Thomas Jefferson to Robert Patterson, March 2, 1803 Thomas Jefferson writes to Robert Patterson of the planned expedition west, asking him to help prepare Meriwether Lewis for taking geographical measurements.
March 15, 1803 | Letter Robert Patterson to Thomas Jefferson, March 15, 1803 Robert Patterson explains the mathematical formulas he will show Meriwether Lewis in preparing him for his journey. Please note, the complex nature of the formulas and examples makes it more feasible to leave them off of the transcribed document than include them; see the images for a complete rendition of Patterson's work.
April 27, 1803 | Letter Thomas Jefferson to Meriwether Lewis, April 27, 1803 Thomas Jefferson informs Meriwether Lewis he will be forwarding copies of his instructions for the journey into the Louisiana Territory. The instructions may be shown to members of the American Philosophical Society, in case they would make any modifications.