Magnetic Compass with Sights
- 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.
- 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)
- 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