After training with Andrew Ellicott in Lancaster and seeking advice from Isaac Briggs in Philadelphia, Meriwether Lewis writes in a letter to President Jefferson about “indispensibly necessary” instruments for making celestial observations. In the evening, he dines with friend Mahlon Dickerson.
Octant
From the personal collection of Norman Anderson. Photo © 2023 by Kristopher K. Townsend. Permission to use granted under the Creative Commons Attribution-Share Alike 4.0 International license.
Indispensable Instruments
Philadelphia, May 14th. 1803.
Dear Sir,
Mr. [Robert] Patterson and Mr. [Andrew] Ellicott both disapprove of the Theodolite as applicable to my purposes; they think it a delicate instrument, difficult of transportation, and one that would be very liable to get out of order;
The instruments these gentlemen recommend, and which indeed they think indispensibly necessary, are, two Sextants, (one of which, must be constructed for the back observation,) an artificial Horizon or two; a good Arnald’s watch or Chronometer, a Surveyor’s Compass with a ball and socket and two pole chain, and a set of plotting instruments.—
As a perfect knolege of the time will be of the first importance in all my Astronomical observations, it is necessary that the time-keeper intended for this expedition should be put in the best possible order . . . it would be best perhaps to send her to me by some safe hand (should any such conveyance offer in time); Mr. Voit could then clean her, and Mr. Ellicott has promised to regulate her, which, I believe he has the means of doing just now, more perfectly than it can be done any where else in the UStates.—
Your most Obt. & very Humble Servt.
Meriwether Lewis[1]Meriwether Lewis to Thomas Jefferson, Founders Online, National Archives, founders.archives.gov/documents/Jefferson/01-40-02-0281 accessed 2 June 2022. [Original source: The Papers of Thomas … Continue reading
Dinner with Dickerson
Sat. 14. Very pleasant—dined at Mr. Bryans with Capt. Lewis.
—Mahlon Dickerson[2]“The Mahlon Dickerson Diary,” in Letters of the Lewis and Clark Expedition with Related Documents: 1783-1854, 2nd ed., ed. Donald Jackson (Urbana: University of Illinois Press, 1978), 680.
Notes
| ↑1 | Meriwether Lewis to Thomas Jefferson, Founders Online, National Archives, founders.archives.gov/documents/Jefferson/01-40-02-0281 accessed 2 June 2022. [Original source: The Papers of Thomas Jefferson, vol. 40, 4 March–10 July 1803, ed. Barbara B. Oberg. Princeton: Princeton University Press, 2013, pp. 374–375.] |
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| ↑2 | “The Mahlon Dickerson Diary,” in Letters of the Lewis and Clark Expedition with Related Documents: 1783-1854, 2nd ed., ed. Donald Jackson (Urbana: University of Illinois Press, 1978), 680. |
