Gurley Solar Transit

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This is a Standard Precise Transit, Reconnaissance Model (#112-T), with a telescopic solar unit attached to one standard "as constructed for the Bureau of Land Management." It can be used for standard surveys, as well as for determining the solar meridian quickly and efficiently. The signature reads "W. & L. E. Gurley Troy, N.Y., U.S.A." and "461261."
Gurley produced its first example in June 1946, basing it on specifications that the General Land Office (the predecessor of the Bureau of Land Management) had published in June 1944. The "Jos. C. Thoma” inscription on this example refers to Joseph C. Thoma, a General Land Office surveyor who made substantial contributions to its design. Thoma’s widow transferred it to Clyde N. Eldridge, a surveyor and aerial photogrammetrist in Barnesville, Ga., and Eldridge’s brother donated it to the Smithsonian in his memory.
Ref: W. & L. E. Gurley, The Gurley Telescopic Solar Transit (Troy, N.Y., 1959).
W. & L. E. Gurley, Manual of Surveying Instruments (Troy, N.Y., 1951), p. 123.
Currently not on view
W. & L. E. Gurley
place made
United States: New York, Troy
Physical Description
brass (overall material)
glass (overall material)
overall: 13 in; 33.02 cm
overall in case: 15 3/4 in x 9 1/2 in x 9 1/2 in; 40.005 cm x 24.13 cm x 24.13 cm
ID Number
accession number
catalog number
Credit Line
Albert M. Eldridge in memory of Clyde N. Eldridge
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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