Smithsonian - National Museum of American History, Behring Center

 
Physical Sciences Collection - Surveying and Geodesy

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Surveyors' Vernier Compass - click to enlarge

Surveyors' Vernier Compass - click to enlarge

Click photos to enlarge.

Surveyors' Vernier Compass

Catalogue number:
PH*335532

Inscriptions:
"Thos Wall Cleveland O."

Dimensions:
length 17.625 inches; needle 6.875 inches

Discussion:

This is an usually large compass, with an unusual skeletal design. The rim is graduated to 30 minutes. The variation arc on the north arm extends 20 degrees either way, and is read by folded vernier to single minutes. There are two level vials on the south arm. Thomas Wall (1797-1854) worked as an instrument maker in Cleveland, Ohio, in the years 1845-1854.

Further Information:

Compass

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