Smithsonian - National Museum of American History, Behring Center

 
Physical Sciences Collection - Surveying and Geodesy

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Gradienter - click to enlarge

Gradienter - click to enlarge

Click photos to enlarge.

Gradienter

Catalogue number:
PH*247905

Inscriptions:
"No. 1. U.S.G.S."

Dimensions:
horizontal circle 3.5 inches diameter; telescope 8.5 inches long; needle 5.25 inches long

Discussion:
The horizontal circle and vertical arc of this instrument are silvered, graduated to 30 minutes, and read by verniers to single minutes. A trough compass and level vial sit atop the telescope; a circular level sits on the horizontal circle. A micrometer attachment, sometimes termed a gradientor, measures the elevation of the telescope with great precision. The United States Geological Survey transferred this instrument to the Smithsonian in 1907. The words "New November 15 87" are scratched on the underside of the horizontal plate.

Further Information:

Gradienter

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