Smithsonian - National Museum of American History, Behring Center

Physical Sciences Collection - Surveying and Geodesy

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Stenometer - click to enlarge

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Catalogue number:

"FAUTH & CO. WASHINGTON D. C. No. 2056" and "Zeiss Field-Glass Power-8. Bausch & Lomb Optical Co. NEW YORK. ROCHESTER, N. Y. CHICAGO"

4.25 inches long


William J. Peters of the United States Geological Survey devised this type of instrument in 1898, while doing reconnaissance work in Alaska. G. 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.G.S., which transferred this stenometer to the Smithsonian in 1907, reported that "Distances up to 1 or 2 miles can be determined with sufficient accuracy for reconnaissance work." This stenometer is a composite instrument. The prism monocular was probably made by Bausch & Lomb in Rochester, N.Y., according to the design developed by Zeiss in Jena, while Saegmuller made the divided object glass micrometer. It is notably different from the stenometer that Saegmuller was offering in 1901, and so is probably an early prototype. The words "U.S.G.S. No. 4" are scratched onto its surface.

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

N.M.A.H. accession file #47,736.

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