Trigonometer for Use with Artillery

Object Details

Description: The solution of right and oblique triangles is central to firing artillery. This circular disc is marked around the edge with scales labeled D (inverse sine), E (logarithmically divided), B (inverse cosine), and C (tangent and cotangent) This side also is marked: SOLUTION OF RIGHT TRIANGLE. Two clear plastic arms, one long (L) and one short (S), are held by a metal pivot at the center. A table in the center of the disc explains how to set arms L and S to solve for different sides of the triangle and/or an acute angle, given different other sides and/or an angle. The instrument is marked on the other side: SOLUTION (/) OF OBLIQUE ANGLES and has a similar table. It is also marked on this side: SOLUTION TO THE TRIAL SHOT DATA PROBLEM. Below this is a grid of lines like those on graph paper for plotting relevant observations.; A signature on the object reads: CAND. B.C. KEENEY (/) BAIM PLAT (/) AAA CAMP DAVIS, N. C. There is no maker's mark.; According to the Brown University Archives, Barnaby Conrad Keeney (1914-1980) was an officer candidate the Antiaircraft Artillery School at Camp Davis, North Carolina, in 1942. Keeney would be discharged from the Army as a captain. He went on to become the twelfth president of Brown University.
Location: Currently not on view

ca. 1942

Object Name: Rule, Circular; trigonometer; calculating instrument, trigonometric

Physical Description: plastic (overall material); wood (overall material); white (overall color); green (overall color); metal (overall material)
Measurements: average spatial: .5 cm x 32.5 cm x 31 cm; 3/16 in x 12 25/32 in x 12 7/32 in

See more items in: Medicine and Science: Mathematics; Trigonometry; Science & Mathematics

National Museum of American History

GUID (Link to Original Record): https://n2t.net/ark:/65665/ng49ca746a9-ca80-704b-e053-15f76fa0b4fa