ALS (RC), Philadelphia. Sending a thermometer with directions for recording the temperature of a cave; giving news of the treaty and recent Congressional business; and providing a diagram and suggestions for an improved water wheel. 2 pp. Housed with a group of printed pages relating to meteorological observations and the 1793 outbreak of yellow fever in Philadelphia, with handwritten annotations (not by Jefferson). 16 pp. [Jefferson letter published in Vol. 6: 347-9]

ALS (RC), Monticello. Planning for the payment and pick-up of iron pans (used to obtain salt from seawater), mentioning the relative success of the draft, and asking whether Zane might part with his spirit level. 1 p. [Vol. 2: 174-5]

ALS to Morris, Hackensack. Asking Morris to conduct some business with his father. 1 p.