Smithsonian - National Museum of American History, Behring Center

 
Physical Sciences Collection - Surveying and Geodesy

Browse Makers | Browse Instruments | Index

Back
 

Theodolite - click to enlarge

Click photos to enlarge.

Theodolite

Catalogue number:
PH*316513

Inscriptions:
"U. S. C. S. No. 100"

Dimensions:
horizontal circle 12 inches diameter; telescope 2.375 inches aperture and 24 inches long

Discussion:

This instrument, sometimes referred to as a 12-inch repeating circle, was made in the Instrument Division of the United States Coast Survey. It dates from before 1878, when the Coast Survey became the Coast and Geodetic Survey. The horizontal circle is graduated to 10 minutes, and read by opposite verniers and magnifiers to 6 seconds.

Ref: C. A. Schott, "Determination of the Astronomical Azimuth of a Direction," United States Coast Survey Annual Report (1866), Appendix No. 11.

Further Information:

Theodolite

Back