1Ennion Williams: List of claims for improvements at Monticello, 19 Sept. 1822, 19 September 1822 (Jefferson Papers)
Emmion Williams’s Claims for Improvements 1. A semicircular Instrument— Radius—12 Inches—Needle 24 Inches } Telescope 11 Inches—with a Nonius attachd. 2. A Drafting Instrument—Semicircular—Radius. 7 Inches, with diagonals crossing Ten circles, showing tenths of the Degrees—also a Scale of equal Parts on the Diameter, and a Centre Pin conveniently seen and may be set readily on any Line or Point...
2To Thomas Jefferson from Ennion Williams, 13 January 1823 (Jefferson Papers)
Being desirous of promoting the Interest of the University, I called upon our friend Bernard Peyton for one of the ground Plans of the University of Virginia; which I have colour’d in such a manner as at a Glance the various Gardens, Yards, Lawns and Buildings can be distinguish’d; to which are added the Elevations of the Rotunda, the Pavilions and Hotels, adjoining their respective ground...