Keuffel & Esser Triangle for Roof Pitches

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This 4" 45°-45°-90° triangle is made of hard black rubber. One edge is marked: KEUFFEL & ESSER (/) N.Y.; TRADE MARK (below the K&E eagle logo). The hypotenuse is marked: 1/2 PITCH. At least as early as 1880, K&E sold this object as part of a set of six hard rubber triangles with various angle sizes. The triangles were used for depicting roof pitches in architectural drawings. In 1890 and 1892 the set sold for $3.00 as model number 1805. By 1906 the set was made of transparent xylonite (plastic).
The triangle was found in the NMAH Physical Sciences collections in 1979 with objects that suggest an association with Cleveland Abbe (1838–1916), an American engineer, astronomer, and meteorologist who worked for the U.S. Weather Service from 1871 until shortly before his death.
References: Catalogue of Keuffel & Esser Co., 13th ed. (New York, 1880), 131; Catalogue of Keuffel & Esser Co., 21st ed. (New York, 1890), 135; Catalogue of Keuffel & Esser Co., 23rd ed. (New York, 1892), 135; Catalogue of Keuffel & Esser Co., 32nd ed. (New York, 1906), 223; accession file.
Currently not on view
date made
Keuffel & Esser Co.
place made
United States: New York, New York
Physical Description
rubber (overall material)
overall: 10 cm x 10 cm x .1 cm; 3 15/16 in x 3 15/16 in x 1/32 in
ID Number
catalog number
accession number
Drawing Instruments
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Squares and Triangles
Data Source
National Museum of American History


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