French-Style Sector

The arms of this brass instrument have straight edges, but the hinge is decorated with a sunburst. One side has double scales of chords, running from 10 to 180; of architectural drawings, running from 5 to 60; and for the specific weights of four metals, marked with their symbols. The outer edge has a scale that runs from 1/4 to 64 and is labeled Calibres des Pieces. There is no maker's mark.
The other side has double scales for equal parts, running from 0 to 200; for solids, running from 5 to 60; and for the lengths of the sides of inscribed regular polygons, from 12 sides to three sides. The outer edge has a scale running from 1/4 to 64 and labeled Poids des Boulets. The outside face of the instrument has scales for English feet and French feet, each running from 1 to 6. This instrument was found in Smithsonian storage in 1956.
Currently not on view
Object Name
date made
18th century
Physical Description
brass (overall material)
overall: .3 cm x 17.5 cm x 3.2 cm; 1/8 in x 6 7/8 in x 1 1/4 in
place made
France: Île-de-France, Paris
ID Number
catalog number
accession number
Science & Mathematics
Rule, Calculating
See more items in
Medicine and Science: Mathematics
Data Source
National Museum of American History, Kenneth E. Behring Center
Additional Media

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