Trigonometric Computing Device - Trigonograph

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This cardboard instrument is in the shape of an isosceles right triangle with an arm pivoted from a forty-five degree angle at the top. It is designed for finding a wide variety of trigonometric functions (sines, cosines, tangents, cotangents, secants and cosecants) and for solving right triangles when only some of the angles or sides are known. It also can be used to solve oblique triangles, for multiplication, for division, for proportions, in problems involving a coefficient of friction, with stress diagrams, and with force diagrams. Also in the envelope holding the instrument is a cardboard scale of inches. Instructions are provided in an accompanying pamphlet.
The triangular envelope that holds the Trigonograph indicates that it sold for fifty cents and was copyrighted by the Chemical Rubber Publishing Company of Cleveland, Ohio.
The term Trigonograph was copyrighted by Julius Stevens Ronay of Lakewood, Ohio in 1931. Ronay (1888-1965) was a native of Hungary who emigrated to the United States in 1913 and by 1920 was working as a draftsman in an adding machine company in Cincinnati. By 1928, he had moved to Cleveland, where he worked until at least his 1942 draft registration.
Ronay was the coauthor of the pamphlet that accompanies the Trigonograph in the collections. The other author was L. E. Glueck, a research engineer at Chemical Publishing Company. This particular Trigonograph was owned by the microscopist Oscar W. Richards (1902-1988), who stamped it: October 20 1934. At that time, Richards was at Yale University.
Currently not on view
Chemical Rubber Publishing Company
place made
United States: Ohio, Cleveland
Physical Description
paper (overall material)
metal (rivet material)
overall: .2 cm x 25 cm x 24.8 cm; 3/32 in x 9 27/32 in x 9 3/4 in
ID Number
nonaccession number
catalog number
Credit Line
Gift of Oscar W. Richards
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Data Source
National Museum of American History


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