Squares & TrianglesTriangles
The triangles in the mathematics collections illustrate the products sold by leading American makers of drawing instruments, including Darling, Brown & Sharpe of Providence, R.I.; and Keuffel & Esser of New York City. An American inventor, LeRoy J. Leishman, devised the Arcascope triangle and combination instrument. The objects on this page also show a transition from triangles made from steel, wood, and rubber to triangles made from plastic. The change in materials in the early 20th century has created a problem for preserving these instruments, as celluloid-based plastics are chemically unstable. Several of these objects are deteriorating despite efforts to store them in a controlled environment.
"Squares & Triangles - Triangles" showing 1 items.
- 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
- ID Number
- catalog number
- accession number
- Data Source
- National Museum of American History, Kenneth E. Behring Center