Gurley Transit

Description
Surveyors who carry instruments long distances, often over difficult terrain, are always concerned about weight. W. & L. E. Gurley made their first lightweight instrument—an aluminum transit—in 1876. But the prohibitive cost of aluminum kept them from manufacturing instruments of this material. Following World War I, Gurley introduced a line of instruments made of an aluminum alloy named Lynite. This transit is of that sort. Gurley termed it a Lightweight Engineers' Transit and sold it, with tripod, for $275. It is marked "W. & L. E. GURLEY TROY N.Y., U.S.A. 3028." The serial number indicates that it was the 28th instrument that Gurley made in 1930. The horizontal and vertical circles are silvered, graduated every 30 minutes of arc, and read by opposite verniers to single minutes.
One standard is marked "PATENT 1731848." The reference is to the patent granted to W. L. Egy on October 15, 1929, and assigned to Gurley. This patent described a graduated circle or arc for surveying instruments made of an aluminum alloy.
Ref: W. & L. E. Gurley, Light Weight Transits (Troy, N.Y., 1929).
Location
Currently not on view
Object Name
transit
date made
1930
maker
W. & L. E. Gurley
Measurements
overall: 7 3/8 in; 18.7325 cm; wt: 9.5 lbs
horizontal graduated circle: 6 1/4 in; 15.875 cm
vertical circle: 5 in; 12.7 cm
telescope: 10 in; 25.4 cm
hanging level: 6 in; 15.24 cm
place made
United States: New York, Troy
ID Number
1986.0091.01
accession number
1986.0091
catalog number
1986.0091.01
subject
Measuring & Mapping
Surveying and Geodesy
See more items in
Medicine and Science: Physical Sciences
Surveying and Geodesy
Data Source
National Museum of American History, Kenneth E. Behring Center
cited
W. & L. E. Gurley. Light Weight Transits

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