The boats sail about twenty miles up the Missouri stopping southeast of present Vermillion, South Dakota. While investigating some minerals, Lewis is overcome by caustic fumes. Pvt. Gass is elected to the rank of sergeant replacing Charles Floyd who recently died.
Missouri River near Vermillion, South Dakota
Courtesy U.S. National Park Service.Missouri National Recreational River.
Caustic Fumes
Capt lewis was near being Poisened by the Smell in pounding this Substance I belv to be arsenic or Cabalt. [He] took a Dost of Salts this evening to carry of the effects of (arsenec) or cobalt which he was trying to find out the real quallity
—William Clark
Mineral Specimens
This Bluff contain Pyrites alum, Copperass & a Kind Markesites . . . . arsenic or Cabalt . . . . Cops. ans [copperas] and almin [alum] pure & Straters of white & brown earth of 6 Inch. thick.
—William Clark
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The Lewis and Clark Trail Experience—our sister site at lewisandclark.travel—connects the world to people and places on the Lewis and Clark Trail.
Discover More
- The Lewis and Clark Expedition: Day by Day by Gary E. Moulton (University of Nebraska Press, 2018). The story in prose, 14 May 1804–23 September 1806.
- The Lewis and Clark Journals: An American Epic of Discovery (abridged) by Gary E. Moulton (University of Nebraska Press, 2003). Selected journal excerpts, 14 May 1804–23 September 1806.
- The Lewis and Clark Journals. by Gary E. Moulton (University of Nebraska Press, 1983–2001). The complete story in 13 volumes.
This page was funded in part by the Lewis and Clark National Historic Trail, U.S. National Park Service.
This site is provided as a public service by the
Lewis and Clark Trail Alliance
with cooperation and funding from the following organizations:
- Lewis and Clark National Historic Trail
- Montana Committee for the Humanities
- Idaho Governor's Lewis and Clark Trail Committee
- The Capital Gallery (Lewis and Clark Fort Mandan Foundation)
- Yellowstone Public Radio
Unless otherwise noted, journal excerpts are from The Journals of the Lewis and Clark Expedition, edited by Gary E. Moulton, 13 vols. (Lincoln: University of Nebraska Press, 1983-2001).