Bernard-Germain-Etienne Lacépède (1756-1825). Image from The Spirit of System by Richard W. Burkhardt.

The Corps of Discovery was to be as much a scientific expedition as a territorial venture, as is shown by this letter from Jefferson to Bernard Lacépède (1756-1825), a person (like Jefferson) of many talents: musician and composer of operas, novelist, professor at the Paris Museum of Natural History, and author of a large number of important studies, mostly on reptiles and fish. Jefferson had been an associate of Lacépède and other leading scientists in Paris during his time there as a diplomat, when he also first knew Thomas Paine (1737-1809), the British-born author of Common Sense and The Rights of Man, important texts for the American and French Revolutions and their aftermath. Through Thomas Paine, who had returned to America in 1802, Lacépède had sent Jefferson a copy of his lectures on zoology at the Museum, and Jefferson responded with the hope that the expedition to the West would provide new information about the Mammoth and the Giant Sloth, both mentioned in Lacépède’s text.

Paleontology, the new science tracing the history of extinct species through their fossilized bones, was the creation of the Frenchman, Baron Cuvier (1769-1832). Jefferson’s serious interest in this subject, of which he was one of the first American scholars, can be compared with other deep interests of his, in native American cultures and languages, and in geology and mineralogy. The son of a surveyor, Jefferson was far in advance of most of his fellow-Americans in his vision of mapping the entire continent of North America, which was only at this moment coming into the possession of the United States.

This mapping was first of all literal, and was accomplished in a number of expeditions: among the first were those of John Sibley and William Dunbar in the south and southwest in 1803 and 1804, that of Lewis and Clark westwards in 1804, and the unsanctioned journeys of Zebulon Pike to the (believed) source of the Mississippi in 1805 and southwest through Spanish territory to Colorado in 1806. But Jefferson was at least as interested in other kinds of mapping: creating definitive catalogues of American flora and fauna; surveying the mineral resources of the new territories; and in preserving records of the history and languages of indigenous tribes outside the United States. And as this letter indicates, Jefferson could converse on equal terms with an expert on paleontology, having published the first commentary on the American Mammoth in his Notes on the State of Virginia (1787) and the first study of the fossilized extinct Giant Sloth, in his memoir on the Megalonyx (written 1797).

Dear Sir Washington Feb. 24. 1803

I have just received from Mr. Paine the copy of your Discours l’ouverture de l’an IX, [a description of a course on zoology given in Paris in 1801] which you were so good as to send me. A rapid view of parts of it only assures me of the pleasure I shall receive from a deliberate perusal of the whole the first moment I have to spare. I was struck with the prophetic spirit of the passage pa. 10. 11. “bientot de courageux voyageurs visiteront les sources du Missisipi et du Missouri, que l’oeil d’un European n’a pas encore entrevues [soon daring travelers will visit the sources of the Mississippi and the Missouri, still unseen by European eyes].” It happens that we are now actually sending off a small party to explore the Missouri to it’s source, and whatever other river, heading nearest with that, runs into the Western ocean; to enlarge our knolege of the geography of our continent, by adding information of that interesting line of communication across it, and to give us a general view of it’s population, natural history, productions, soil & climate. It is not improbable that this voyage of discovery will procure us further information of the Mammoth, & of the Megatherium also, mentioned by you page 6. For you have possibly seen in our Philosophical transactions, that, before we had seen the account of that animal by M. Cuvier, we had found here some remains of an enormous animal incognitum, whom, from the disproportionate length of h[is] claw, we had denominated Megalonyx, and which is probably the same animal; and that there are symptoms of it’s late and present existence. The route we are exploring will perhaps bring us further evidence of it, and may be accomplished in two summers.

. . . I pray you to accept assurances of my great consideration and respect.

TH: JEFFERSON

Source: Jackson, Letters, item 10.

Further Reading: Greene, John C. American Science in the Age of Jefferson. Ames: The Iowa State University Press, 1984.
Jefferson, Thomas. “A Memoir on the Discovery of certain Bones of a Quadruped of the clawed Kind in the Western Parts of Virginia.” Transactions of the American Philosophical Society 4 (1799), 246-60, 258-9. Reprinted as “Memoir on the Megalonyx” in The Papers of Thomas Jefferson, ed. Barbara B. Oberg et al., vol. 29, pp. 291-304, Princeton and Oxford: Princeton University Press, 2002.