More than a mere military expedition, the journey of Lewis & Clark was a true voyage of discovery, a paragon of the systematic scientific observation of nature that epitomized the Age of Enlightenment.
Jefferson's instructions to Meriwether Lewis set out an ambitious agenda, not only to map the uncharted wilderness of the American west and establish friendly relations with the Indians who lived there, but also to conduct detailed observations of flora and fauna, of climate, of soils and minerals, even of fossils of extinct species.
Prior to the journey, Lewis received special training in scientific methods and in the use of instruments such as the sextant, telescope, and chronometer. He brought with him on the journey an extensive—and heavy!—library of scientific references, including books on botany, mineralogy, and astronomy.
Lewis and Clark's journals were peppered with careful illustrations of newly discovered species; the explorers collected more than 300 specimens of plants and animals for shipment back to Washington, D.C. Three animals—two magpies and a prairie dog—even made it back alive.
Considering the obstacles faced by Lewis & Clark in simply surviving their journey, the quality and quantity of their scientific observations were truly remarkable.