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 "W. & L. E. Gurley Troy, N.Y." signature indicates a date of manufacture after 1876. The lack of serial number indicates a date before 1908.
Ref: W. & L. E. Gurley, A Manual of the Principal Instruments Used in American Engineering and Surveying (Troy, N.Y., 1904), pp. 108-120.
Location
Currently not on view
maker
W. & L. E. Gurley
place made
United States: New York, Troy
Measurements
overall length: 15 1/2 in; 39.37 cm
needle: 6 in; 15.24 cm
overall in case: 4 13/16 in x 16 1/2 in x 8 1/2 in; 12.22375 cm x 41.91 cm x 21.59 cm
ID Number
PH.335209
catalog number
335209
accession number
317998
Credit Line
Columbia University
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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