Lot 50: Jefferson, Thomas. Autograph manuscript signed, 2 pages (7 1/8 x 4 ½ in.; 181 x 114 mm.)
December 18, 2012
Calabasas Hills, CA, USALive Auction
50. Jefferson, Thomas. Autograph manuscript signed twice with initials in the text (“Th: J”), and twice in the text for his grandson, (“Th: J.R.”), two pages (7 1/8 x 4 ½ in.; 181 x 114 mm.), “Monticello,” [November - December 1811]; some smudging.
Jefferson’s solar observations at Monticello with his grandson.
In the present manuscript, Jefferson records solar observations made by himself and his teenage grandson, Thomas Jefferson Randolph, at Monticello. In part, their observations appear to involve the testing of their instruments, as Jefferson’s notes include allowances for error of instrumt as well as calculations for degrees of refraction . . . parallax . . . true altitude . . . Zenith distance . . . declination [from] Greenwich and latitudes of Willis’s Mount and Monticello. Some observations are introduced by substantial narrative passages such as, Latitude of Willis’s mountain by observations of the Sun; meridian altitude taken from the peak on the right side of the gap, & next adjacent to it, as seen from Monticello while others are briefer. Jefferson’s integral signatures appear when he assigns credit for his own or his grandson’s readings, as in Th: J’s observation Nov. 21. . . and Th: J.R’s observn of Dec. 18.
A solar eclipse was visible and witnessed at Monticello on 11 September 1811, and it is likely that this astronomical event prompted Jefferson and his grandson to undertake their observations herewith. A fascinating manuscript revealing Jefferson’s wide and varied interests as well as his desire to impart both knowledge and intellectual curiosity upon his grandson.