Thomas Jefferson Papers

From Thomas Jefferson to Meriwether Lewis, 30 April 1803

To Meriwether Lewis

Washington Apr. 30. 1803

Th: Jefferson to Capt. Lewis

I think we spoke together of your carrying some steel or cast iron1 corn mills to give to the Indians or to trade with them, as well as for your own use. lest however I should be mistaken, I mention them now. I make no doubt you have consulted with mr Ellicot as to the best instruments to carry. I would wish that nothing which passed between us here should prevent your following his advice, which is certainly the best. should a timepiece be requisite, it is probable mr Garnet can furnish you one. neither Ellicot nor Garnet have given me their opinion on the substituting a meridian at land, instead of observations of time, for ascertaining longitude by the lunar motions. I presume therefore it will not answer. accept my affectionate salutations.

PrC (DLC); endorsed by TJ in ink on verso.

corn mills: an iron mill for grinding corn was on Lewis’s list of needs for camp equipage. The purveyor’s office in Philadelphia bought one mill for that purpose for $9 and two others for the stock of presents for $20. The implement for the expedition’s use weighed 20 pounds and the two others weighed a total of about 53 pounds (Jackson, Lewis and Clark description begins Donald Jackson, ed., The Letters of the Lewis and Clark Expedition, with Related Documents, 1783–1854, 2d ed., Urbana, Ill., 1978 description ends , 1:71, 84, 94, 95).

TJ had thought that if Lewis used a theodolite or universal equatorial instrument he would not need a precision timepiece such as a chronometer to make observations for longitude (Silvio A. Bedini, Thomas Jefferson: Statesman of Science [New York, 1990], 344–6).

mr garnet: John Garnett’s cousin, Horatio Gates, called him “a Man of much Science.” A wealthy resident of New Brunswick, New Jersey, who was born in England, Garnett made celestial observations, edited and published nautical almanacs and astronomical tables, was a scientific farmer, and wrote papers on astronomical methods, mathematics, and windmill technology. The American Philosophical Society elected him to membership in July 1802 and awarded him a gold medal in 1807 for innovations in navigational charts (same, 341–2; John C. Greene, American Science in the Age of Jefferson [Ames, Iowa, 1984], 141–2, 147; William H. Benedict, New Brunswick in History [New Brunswick, N.J., 1925], 53, 134–6; APS description begins American Philosophical Society description ends , Proceedings, 22, pt. 3 [1884], 311, 326, 344, 376, 400; APS description begins American Philosophical Society description ends , Transactions, 6 [1809], 303–18, 391–8; Vol. 30:110; Vol. 36:50–1; Robert Patterson to TJ, 7 Feb. 1807, in DLC).

1Preceding four words interlined.

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