Measuring A River - Lewis and Clark - Gasconade, MO
Posted by: YoSam.
N 38° 40.071 W 091° 33.327
15S E 625671 N 4280908
Quick Description: Clark read the sextant to measure latitude. He took sightings at regular intervals.
Location: Missouri, United States
Date Posted: 5/9/2008 9:52:55 AM
Waymark Code: WM3R5A
Marker Erected by: Missouri Department of Conservation.
County of Marker: Gasconade County.
Location of Marker: East end 1st St., @ Gasconade River Park.
"May 28th, Munday, 1804
...I measured the river found the Gasconnade to be 157 yds. wide and 19 foot Deep the Course of this R. is S 29° W...onloaded the large Peroque on board of which was 8 french hands found many things wet by their cearlessness, put all the articles which was wet out to Dry..." William Clark
The maps of William Clark tell the story of a river unbounded. From Clark's simple drawings with quill and ink, comes the map here. [ed. shown across top of interpretive sign] River channels were drawn according to Clark's instructions and historic notes were linked with modern photographs and satellite images to contrast the two Missouri River paths.
In the early 1800s, maps of central North America were nearly blank. Lewis and Clark were equipped with the best instruments of their time to measure the landscape. Clark recorded sandbars, islands, cliffs, creeks and other landmarks, then sketched out crude maps. After Clark returned, he combined his maps with notes from fellow travelers to create a large map of the United States.
Mapmakers still marvel at the accuracy of Clark's maps and the river they reveal. The maps are invaluable in comparing the historical river with the river of today. The Missouri River is ever changing through floods and waterway movements and remains a challenge to measure and map.
William Clark read the sextant to measure latitude (see illustration). He took sightings at given times each day using a timepiece for precision and a telescope for celestial observations. Clark's journal maps have amazing accuracy to illustrate the Missouri River's changing channels.