William J. Peters of the U. S. Geological Survey devised a split objective range finder in 1898, while doing reconnaissance work in Alaska. George N. Saegmuller, proprietor of Fauth & Co., explained its function: "Having a fixed base of known dimensions defined by targets, the measurement is made by bringing the images of the targets together by moving the halved objective by means of a micrometer screw." The U.S. Geological Survey transferred this example to the Smithsonian in 1909, reporting that "Distances up to 1 or 2 miles can be determined with sufficient accuracy for reconnaissance work." This seems to be an early example. "U.S.G.S. No. 3" is scratched onto its surface.

Ref: George N. Saegmuller, Descriptive Price-List of First-Class Engineering & Astronomical Instruments (Washington, D.C., 1901), p. 108.

Date Made: ca. 1900

Location: Currently not on view

See more items in: Medicine and Science: Physical Sciences


Exhibition Location:

Credit Line: U. S. Geological Survey

Data Source: National Museum of American History

Id Number: PH.252977Accession Number: 49676Catalog Number: 252977

Object Name: stenometer

Measurements: overall: 5.7 cm x 15 cm x 11 cm; 2 1/4 in x 5 7/8 in x 4 5/16 inoverall: 4 1/2 in x 2 5/16 in x 6 1/4 in; 11.43 cm x 5.87375 cm x 15.875 cm


Record Id: nmah_1183941

Our collection database is a work in progress. We may update this record based on further research and review. Learn more about our approach to sharing our collection online.

If you would like to know how you can use content on this page, see the Smithsonian's Terms of Use. If you need to request an image for publication or other use, please visit Rights and Reproductions.