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Magnetic Compass with Sights

Object Details

Description
This magnetic compass has a paper scale, a metal needle, a wooden case, and a glass cover. The scale is graduated every 10 grads and marked every 20, with a total of 400 grads in the circle. Folding metal sights are attached to the north and south edges. A plumb bob stored in the north edge of the case can be suspended from the east edge.
From ancient times, mathematicians described a right angle as having ninety degrees. In the 1790s, the French introduced a right angle of one hundred decimal degrees or grads. Instruments divided this way were available in France and in the United States into the 20th century.
Location
Currently not on view
Data Source
National Museum of American History
Physical Description
paper (scale material)
metal (needle, sights, plumb bob material)
wood (case material)
Measurements
overall: 1 3/4 in x 8 3/8 in x 4 1/2 in; 4.445 cm x 21.2725 cm x 11.43 cm
overall: 1 in x 8 1/4 in x 4 1/2 in; 2.54 cm x 20.955 cm x 11.43 cm
Object Name
magnetic compass

Featured In

  • Metric System Demonstration Apparatus:The Origin of the Metric System
Magnetic Compass with Sights
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