Telescopic Alidade

Telescopic Alidade

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Gurley began offering telescopic alidades in 1884, explaining that “This instrument, which has been so largely employed abroad in topography and map drawing, is now fast coming into use in our own country, especially in colleges and schools where the study of surveying is pursued.” This example belonged to Gettysburg College and is marked “W. & L. E. GURLEY TROY, N.Y.” The lack of serial number indicates that it was made before 1908. It has an erecting telescope with level above, and a vertical circle that is graduated to 30 minutes and read by vernier to single minutes. There is also a box compass with level vials, a plumbing bar, and a plumb bob.
Ref: W. & L. E. Gurley, A Manual of the Principal Instruments Used in American Engineering and Surveying (Troy, N.Y., 1893), pp. 215-224.
Currently not on view
Object Name
alidade (telescopic)
W. & L. E. Gurley
place made
United States: New York, Troy
overall in case: 6 1/4 in x 21 1/16 in x 10 1/4 in; 15.875 cm x 53.49875 cm x 26.035 cm
ID Number
accession number
catalog number
Credit Line
Gettysburg College
See more items in
Medicine and Science: Physical Sciences
Measuring & Mapping
Surveying and Geodesy
Data Source
National Museum of American History
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