Darling, Brown & Sharpe Open Triangle

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This steel 45°-45°-90° triangle is 8" tall and has an open interior. A hole near one vertex is for hanging. The instrument is marked: Darling, Brown & Sharpe (/) Providence, R.I. The firm operated under that name from 1866 to 1892. (Compare to 1977.0460.08 and 1977.0460.09.) It advertised this triangle in 1868 for $4.50 and for $4.00 in 1887 and 1899 (when the company was known as Brown & Sharpe). In 1884 the Physical Laboratory of the University of California in Berkeley purchased a triangle of this type from Darling, Brown & Sharpe for $4.25.
Erasmus Darwin Leavitt Jr. (1836–1916), the renowned American mechanical engineer and designer of steam engines, owned this triangle. It was donated to the Smithsonian by his granddaughter.
References: Kenneth L. Cope, intro., A Brown & Sharpe Catalogue Collection, 1868 to 1899 (Mendham, N.J.: The Astragal Press, 1997), 14, 118, 157; "Disbursements," in Annual Report of the Secretary to the Board of Regents of the University of California, for the Year Ending June 30, 1884 (Sacramento, 1884), 50.
Currently not on view
date made
Darling, Brown & Sharpe
place made
United States: Rhode Island, Providence
Physical Description
steel (overall material)
overall: 20.4 cm x 20.4 cm x 3/16 in; 8 1/32 in x 8 1/32 in x .508 cm
ID Number
catalog number
accession number
Credit Line
Gift of Margaret van D. Rice
Drafting, Engineering
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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