Drafting Triangle

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This 6-1/4" 30°-60°-90° wooden triangle has a 1-1/8" round hole at the center for positioning and holding the instrument. The hole is larger than those in 1979.0876.02 and MA.335331. Cursive initials "D. D." are engraved near the 60° angle.
The donors' family was prominent in the history of American science. John William Draper (1811–1882) was a chemist who also made innovations in photography. He had three sons: John C. Draper (1835–1885), who was a physician and chemist; Henry Draper (1837–1882), who was an astronomical photographer; and Daniel Draper (1841–1931), who established the New York Meteorological Observatory in Central Park in 1868 and directed it until 1911. The initials on the object suggest Daniel owned the triangle.
References: Maya Hambly, Drawing Instruments, 1580–1980 (London: Sotheby's Publications, 1988), 108–109; Robert S. Harding and Jeffrey L. Tate, "Draper Family Collection, ca. 1826–1936," Archives Center, National Museum of American History, http://amhistory.si.edu/archives/d8121.htm.
Currently not on view
date made
late 19th century
Physical Description
wood (overall material)
overall: 9.2 cm x 15.7 cm x .3 cm; 3 5/8 in x 6 3/16 in x 1/8 in
ID Number
catalog number
accession number
Credit Line
Gift of John William Christopher Draper and James Christopher Draper
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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