Smithsonian - National Museum of American History, Behring Center

 
Physical Sciences Collection - Surveying and Geodesy

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Alidade
Altitude and Azimuth Instrument
Chain, Tape and Base Bar
Compass, Pocket
Compass, Railroad
Compass, Solar
Compass, Surveyor's
Cross, Surveyor's
Electromagnetic Distance Measurement (EDM)
Gradienter
Graphometer
Heliotrope
Holland Circle
Level
Range Finder
Repeating Circle
Theodolite
Transit
Transit and Equal Altitude
Transit, Geodetic
Universal Instrument
Vertical Circle
Waywiser
Zenith Telescope
Miscellaneous

 

Theodolite

Leonard Digges introduced the word "theodolitus" in his Pantometria (London, 1571). This surveying instrument had a circular ring or plate divided into 360 degrees, and a pivoting alidade with sight vanes at either end. Theodolites of this sort, as well as others with a second pair of sight vanes affixed to the graduated circle, were soon in widespread use. In 1791, George Adams Jr. called this instrument a "common theodolet," reserving the term theodolite for the telescopic instruments with horizontal circles and vertical arcs that had been introduced in London in the 1720s. While the telescopic theodolite was popular in England, Americans preferred the surveyor’s compass and, later, the surveyor’s transit, which were cheaper and more robust. In the 18th century form, the telescope is mounted directly on the vertical arc. In the transit theodolite, which originated in London in the 1840s, the telescope is transit mounted, with a vertical circle mounted at one side. Heinrich Wild’s optical theodolite, introduced in Switzerland in the 1920s, had several new features, including an auxiliary telescope that lets the user read either circle without moving away from the station.

Some theodolites measure horizontal angles with geodetic accuracy. The first instrument of this sort was made by Jesse Ramsden in London in 1787, and purchased by the Royal Society for use on the geodetic link between Greenwich and Paris. The first instrument of this sort in America was made around 1815 by Troughton in London for the fledgling United States Coast Survey.

Ref:

 J. A. Bennett, The Divided Circle (Oxford, 1987), pp. 40–41, 146–149, 195–200.

George Adams Jr., Geometrical and Graphical Essays (London, 1791), pp. 220–222 and fig. 5.

Collection:

Adams (common)
Blattner & Adam (common)
Blunt
Brander & Höschel
Casella
Casella (photo)
Elliott Bros. (Eckhold’s Omnimeter)
Fauth #996
Fauth #1993
Fauth (Columbia)
Fauth (U.S.C.&G.S.)
Gambey
Gilbert
Hagger
Houghton, Rowland (common)
Jones, Thomas
Kern (DKM2) #37845
Kern (DKM2) #81066
Kern (DKM3) #142200
Kübel
Lingke
Patten
Secretan
Sisson
Troughton & Simms
Troughton & Simms (Lowell, Mass.)
unmarked
unmarked (Troughton & Simms)
unmarked (U.S.C. & G.S. No. 145)
unmarked (U.S.C. & G.S. No. 308, Parkhurst type)
unmarked (U.S.C.S. No. 100)
White, David
Wild Heerbrugg (RDS)
Wild Heerbrugg (T2) #50903
Wild Heerbrugg (T3) #91599
Wild, Heinrich (T2) #218
Wright, Tho. (common)
Würdemann #163
Zeiss #34390
Zeiss (Total Station)