Darling, Brown & Sharpe Drafting Triangle

This steel 45°-45°-90° triangle is 10" tall. A hole near one vertex is for hanging. The instrument is marked: D. B. & S. Prov. R. I. (/) E. D. LEAVITT. The pattern of tarnish marks on the instrument suggests that the user stacked other triangles, including 1977.0460.10, on top of this triangle for making engineering drawings and for storage.
D. B. & S. is the mark for Darling, Brown & Sharpe of Providence, R.I. Samuel Darling, a machinist who invented numerous drafting instruments, partnered with Joseph R. Brown and Lucian Sharpe between 1866 and 1892. For more on the history of Darling, Brown & Sharpe, see 1977.0460.01, 1977.0460.05, and 1977.0460.06. Company catalogs published in 1868 and 1887 depict only open triangles, not solid ones.
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); Henry Dexter Sharpe, A Measure of Perfection: The History of Brown & Sharpe (North Kingston, R.I.: Brown & Sharpe, 1949), http://www.roseantiquetools.com/id44.html.
Currently not on view
Object Name
date made
Darling, Brown and Sharpe
Physical Description
steel (overall material)
overall: 25.5 cm x 25.5 cm x .2 cm; 10 1/32 in x 10 1/32 in x 3/32 in
place made
United States: Rhode Island, Providence
ID Number
catalog number
accession number
Squares and Triangles
Science & Mathematics
Drafting, Engineering
Drawing Instruments
See more items in
Medicine and Science: Mathematics
Squares and Triangles
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of Margaret van D. Rice

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