Telescopic Alidade

Description
This alidade has a telescope with a level mounted above, and a vertical circle that is silvered, graduated to 30 minutes, and read by vernier to single minutes. The base has six large circular holes, and a circular level vial. The U.S. Geological Survey transferred it to the Smithsonian in 1907, describing it as a "preliminary type" of alidade devised for the Survey about 1890.
Location
Currently not on view
Object Name
alidade (telescopic)
Measurements
base: 26 in; 66.04 cm
telescope: 11 1/2 in; 29.21 cm
ID Number
PH*247914
catalog number
247914
accession number
47736
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

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