Smithsonian - National Museum of American History, Behring Center

 
Physical Sciences Collection - Surveying and Geodesy

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Surveyor's Vernier Compass - click to enlarge

Surveyor's Vernier Compass - click to enlarge

Surveyor's Vernier Compass - click to enlarge

Click photos to enlarge.

Surveyor's Vernier Compass

Catalogue number:
PH*333647

Inscriptions:
"T. R. RANDOLPH CINCINNATI. O." and "1234" and "PATENTED JUNE 24 '79"

Dimensions:
7 inches diameter

Discussion:
On June 24, 1879, Theodore F. Randolph received a patent (#216,759) for a surveyor's compass with a telescope sight, in which the telescope and its supports can be detached from the compass. In this example (which is missing the telescope and its supports) the raised rim is silvered, and graduated to 30 minutes. The variation arc, which is located on the compass face, extends 25 degrees either way, and reads by double vernier to single minutes. The carrying case is marked "PATENTED NOV. 9, 1880," referring to Randolphs' patent (#234,331) for a seamless leather container of this sort. This instrument belonged to the University of Missouri at Columbia.

Ref: T. F. Randolph, Illustrated Catalogue and Price List (Cincinnati, 1892), p. 2.

Further Information:

Randolph
Surveyor's Compass

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