Thomas Jefferson Papers

To Thomas Jefferson from Robert Patterson, 18 June 1803

From Robert Patterson

Philada. June 18th. 1803—


I recommended to Capt. Lewis, the use of a statistical Table, in which to set down his Astronomical observations, in the course of his intended expedition; as an expedient that would save a great deal of time, and be productive of many other obvious advantages. I had proposed to draw him out a sketch of such a table, but an unusual hurry of business prevented me, while he was in the city—I have now, however, fulfilled my promise—and transmit the inclosed for his inspection.

I have sent it under cover to you, Sir, lest Capt. Lewis may have proceeded on his tour; in which case, if you shall judge it worth his notice, you will have the trouble of forwarding it to him—

I am Sir with the highest respect & esteem—Your Obed. Servt.—

R. Patterson

RC (DLC); endorsed by TJ as received 21 June and so recorded in SJL. Enclosure: see below.

The blank frame of a statistical table that Patterson drew up for Meriwether Lewis has not been found, but Lewis copied it for the notebook of astronomical problems and instructions he had received from the Philadelphia mathematician (see Patterson to TJ, 15 Mch.). The table, for recording the astronomical observations that Patterson wanted Lewis to make regularly, included columns for the place where an observation was made; the date; the apparent time, mean time, and time by the watch; the error of the watch against the mean time and the watch’s daily gain or loss of time; the apparent altitude of the sun’s center or its lower or upper edge (limb); the true altitude of the sun’s center; the apparent altitude of the moon’s center or edge; the true altitude of the moon’s center; the error of the intrument employed for the observation; the name of the star used for an observation; the apparent altitude of the star; the apparent distance of the sun’s or moon’s edge; the apparent and true distances between the moon and the star; the longitude of the place of observation from Greenwich; the latitude; the magnetic azimuth of the sun or pole star, the true azimuth, and the variation of the magnetic needle; and notes relating to the observation (MS in MoHi, in astronomical notebook, in Lewis’s hand).

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