1William Lambert to Thomas Jefferson, 23 April 1812 (Jefferson Papers)
I transmit to the American philosophical Society , an abstract of such calculations as I have hitherto made to determine the longitude of the Capitol in this city from Greenwich observatory, in England . The variation in the results will be found, on examination, to arise more from probable errors in the data, or in the lunar tables from which the positions in the Nautical Almanac have been...
2William Lambert to Thomas Jefferson, 20 April 1812 (Jefferson Papers)
By a letter from M r John Garnett , Editor of the American impression of the Nautical Almanac, at N. Brunswick , in New-Jersey , it is stated, that an error has been discovered (probably at Greenwich ) in M r M. de la Place’s computations relating to the true form of the Earth, which being corrected, the ratio of 320 to 319, of the equatorial diameter to the polar axis of the Earth, seems now...
3William Lambert to Thomas Jefferson, 9 January 1812 (Jefferson Papers)
The inclosed abstract of calculation relative to the longitude of Monticello from Greenwich by the apparent times of internal contacts of Sun and Moon on the 17 th of September last, will, it is hoped, be accepted by you as an accurate result, admitting the data to be correctly stated. Having in a former communication, given rules for ascertaining the altitude and longitude of the nonagesimal,...
4William Lambert to Thomas Jefferson, 8 January 1812 (Jefferson Papers)
I have the honor to transmit an abstract of the calculation of the longitude of Monticello west of Greenwich, founded on the apparent times of the internal contacts of Sun and Moon on the 17 th of September last, as contained in your letter of the 29 th of December ; and having ascertained the elements with scrupulous exactness, tested by various rules, the accuracy of the result, according to...
5William Lambert to Thomas Jefferson, 22 November 1811 (Jefferson Papers)
The observations relating to the solar eclipse of the 17 th September last , were made in this city opposite Rhodes’s hotel , North 71.º West, 1. ⅜ . m American measure, from the Capitol . The apparent times of the principal appearances, to the nearest second, are as follow:— h. m. s. Beginning of the Eclipse, 0. 22. 9.
6Enclosure: William Lambert’s Calculation of Monticello’s Longitude from Greenwich, 14 November 1811 (Jefferson Papers)
Calculation of the longitude from Greenwich , of Monticello , in Virginia , from the solar eclipse of the 17 th of September, 1811 . Latitude 38.° 8′ Estimated Longitude, 5. h. 14. m. 0. sec = 78.° 30.′ 0.″ West. Ratio of the equatorial diameter to the polar axis of the earth, 320 to 319. Constant Log. to reduce the latitude (320 to 319) 9.9972814. Lat. of the place 38.° 8.′ 0″ log. tangent...
7William Lambert to Thomas Jefferson, 14 November 1811 (Jefferson Papers)
The President of William and Mary college having lately sent me the result of your observations of the solar eclipse of Sept r 17 th at Monticello , I have calculated the longitude from Greenwich , using the first and last contacts, which will always give a near approximation to the truth, if the apparent times and latitude of the place have been correctly ascertained. I have taken great pains...