Troughton & Simms Geodetic Transit

This instrument marked "Troughton & Simms, London, 1849" and "U. S. C. S. No. 6" was made for the U. S. Coast Survey in 1849. It has a double-cone horizontal axis, two lamps for illuminating this axis, a large striding level, two small vertical circles attached to the telescope tube, and a solid iron base. By 1880, The Coast Survey had added the eccentric cam apparatus to the base to facilitate the reversal of the telescope.
Ref: "Determination of Time by Means of the Transit Instrument," United States Coast and Geodetic Survey Report (1880): 205-227 and pl. 62.
Object Name
geodetic transit
Troughton and Simms
telescope: 46 in; 116.84 cm
aperture: 3 in; 7.62 cm
striding level: 26 in; 66.04 cm
place made
United Kingdom: England, London
ID Number
accession number
catalog number
See more items in
Medicine and Science: Physical Sciences
Measuring & Mapping
Surveying and Geodesy
Data Source
National Museum of American History, Kenneth E. Behring Center
United States Coast and Geodetic Survey. United States Coast and Geodetic Survey Annual Report
Additional Media

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