Gurley Surveyor's Vernier Compass

Description
The rim of this compass is graduated to 30 minutes. The variation arc on the south arm extends 20 degrees either way, and is read by folded vernier to 2 minutes. Two level vials are on the north arm, and an outkeeper is on the south arm. The side of one vertical sight is graduated to half degrees, for determining angles of elevation or depression. The machine-engraved signature indicates that it was made after 1876. This compass came to the Smithsonian from the University of Missouri at Columbia.
Ref: W. & L. E. Gurley, A Manual of the Principal Instruments Used in American Engineering and Surveying (Troy, N.Y., 1904), pp. 108-120.
W. Skerritt, "W. & L. E. Gurley's Engraving Machine," Rittenhouse 11 (1997): 97-100.
Location
Currently not on view
Object Name
surveyor's vernier compass
maker
W. & L. E. Gurley
Measurements
overall length: 15 1/2 in; 39.37 cm
needle: 6 in; 15.24 cm
place made
United States: New York, Troy
ID Number
PH*333661
catalog number
333661
accession number
300659
See more items in
Medicine and Science: Physical Sciences
Measuring & Mapping
Surveying and Geodesy
Data Source
National Museum of American History, Kenneth E. Behring Center

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