Smithsonian - National Museum of American History, Behring Center

 
Physical Sciences Collection - Surveying and Geodesy

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Surveyor's Vernier Compass - click to enlarge

Surveyor's Vernier Compass - click to enlarge

Click photos to enlarge.

Surveyor's Vernier Compass

Catalogue number:
PH*333661

Inscriptions:
"W. & L. E. Gurley, Troy,

Dimensions:
length 15.5 inches; needle 6 inches

Discussion:

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. There are two level vials on the north arm, and an outkeeper on the south arm. The side of one vertical sight is graduated to half degrees, for determining angles of elevation or depression. This instrument belonged to the University of Missouri at Columbia. The machine-engraved signature indicates that it was made after 1876.

Ref: W. & L. E. Gurley, A Manual of the Principal Instruments Used in American Engineering and Surveying (Troy, N.Y., 1904), pp. 108-120.

Further Information:

Compass
Gurley

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