he route that Lewis & Clark took from St. Louis, Missouri to the Pacific Ocean was long and arduous, lasting 28 months (from May 1804 to September 1806) and comprising 7000 miles. President Thomas Jefferson had strict instructions for the pair of explorers at the outset: to find “the most direct and practicable water communication across this continent for the purpose of commerce.” To accomplish this, it was critical that careful notation be made of latitude and longitude of all “remarkable points” between the mouth of the Missouri River and the Pacific coast.
Merriwether Lewis, Jefferson's secretary from 1801 to 1803, was charged with anticipating and acquiring all material requirements for the expedition. Surveying equipment was a top priority, including a sextant and a pocket compass. This he purchased in Philadelphia for $5.
The same compass used on the expedition is in the collections of the National Museum of American History at the Smithsonian Institution. The path that it took was a much more direct route than the expedition, passing from William Clark. Mary F. McCabe, a descendant and the last private owner of the compass, donated it to the Smithsonian in 1933.
his accurate mahogany reproduction with hinged cover and brass peep sites was originally made in Philadelphia by Thomas Whitney. A silver plated chapter ring is marked in single degrees, 0 to 90, every quarter. The compass rose is marked North by the fleur de lis and in seven point directionals in block. The steel compass needle measures 2.5 inches and is crowned by a brass turning. Closing the lid activates the internal brass plunger and paddle locking mechanism.
The Lewis and Clark Pocket Compass
(Dimensions: 3 1/2-inches square, opened in sight position 5-inches).