Gurley Surveyor's Vernier Compass

Description
This compass is marked "W. & L. E. Gurley, Troy, N. Y." Gurley described this as a "Pocket Railroad Compass with Telescope." The form, with the folding sights offset so that the telescope is aligned with the north south line, was made between 1887 and 1920. The rim is graduated to 30 minutes, and numbered in quadrants from north and south. The outside of the box has a variation arc that extends ± 35 degrees, and that reads by folded vernier to 5 minutes. New, it cost $58.
Ref: W. & L. E. Gurley, A Manual of the Principal Instruments Used in American Engineering and Surveying (Troy, N.Y., 1904), p. 140.
William H. Skerritt, Catalog of the Charles E. Smart Collection of Antique Surveying Instruments (Troy, N.Y., 1996), pp. 36-39.
Location
Currently not on view
Object Name
compass (pocket with telescope)
maker
W. & L. E. Gurley
Measurements
overall: 5 3/4 in; 14.605 cm
needle: 4 1/2 in; 11.43 cm
telescope: 8 3/4 in; 22.225 cm
vertical circle: 3 1/2 in; 8.89 cm
place made
United States: New York, Troy
ID Number
PH*312755
catalog number
312755
accession number
165452
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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