Telescopic Alidade


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.

Maker: W. & L. E. Gurley

Location: Currently not on view

Place Made: United States: New York, Troy

See more items in: Medicine and Science: Physical Sciences, Surveying and Geodesy, Measuring & Mapping


Exhibition Location:

Related Publication: W. & L. E. Gurley. Manual of the Prinicipal Instruments Used in American Engineering and Surveying; 30th Edition

Credit Line: Gettysburg College

Data Source: National Museum of American History

Id Number: 1982.0104.05Accession Number: 1982.0104Catalog Number: 1982.0104.05

Object Name: alidade (telescopic)

Measurements: 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


Record Id: nmah_764356

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