Day-by-Day / November 15, 1803

November 15, 1803

Measuring river widths

At the mouth of the Ohio, Lewis records key measurements from Clark’s survey of the confluence of the Ohio and Mississippi rivers.

William Clark

by Michael Haynes

Drawing of Clark holding a sextant

© Michael Haynes, https://www.mhaynesart.com. Used with permission.

Clark used the sextant to make celestial observations. To measure river widths, his primary tools were a surveyor’s compass and surveyor’s chain. See Deciphering the Celestial Data by Robert N. Bergantino and Formal Navigation by John Logan Allen.

Clark’s Survey

Capt Clark made a partial survey of the point and asscertained by the Circumferenter and projection that the width of the Ohio from[:]

  Yards
The point was— 1274
The Missippi— 1435
and the width of them both from those observed points on their respective banks was— 2002

—Meriwether Lewis

Related: Clark’s Portage Route Survey | Measuring River Widths

 

Experience the Lewis and Clark Trail

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.

Plan a trip related to November 15, 1803:

Logo: Lewis and Clark.travel

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
Logo: Lewis & Clark Trail Alliance
Lewis and Clark Trail Alliance
with cooperation and funding from the following organizations:

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).