Object Details
- 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 seconds. There is an outkeeper on the south arm, and two level vials on the north. The hand-engraved inscription indicates a date of manufacture between 1852 and 1876. New, it cost $50.
- The compass is equipped with a telescope that attaches to one of the sight vanes, and that is marked "W. & L. E. GURLEY, TROY, N.Y. PATENTED JULY 9, 1878." The reference is to patent #205,712 describing an Improvement in Telescope Attachments for Surveyors’ Compasses, and granted to William Gurley and Lewis E. Gurley.
- Ref: W. & L. E. Gurley, A Manual of the Principal Instruments Used in American Engineering and Surveying (Troy, N.Y., 1871), pp. 23-27.
- W. Skerritt, "W. & L. E. Gurley's Engraving Machine," Rittenhouse 11 (1997): 97-100.
- Location
- Currently not on view
- Data Source
- National Museum of American History
- maker
- W. & L. E. Gurley
- Credit Line
- Columbia University
- Measurements
- overall length: 15 1/2 in; 39.37 cm
- needle: 6 in; 15.24 cm
- overall in case: 4 5/8 in x 16 1/2 in x 8 3/8 in; 11.7475 cm x 41.91 cm x 21.2725 cm
- Object Name
- Surveyor's Vernier Compass
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