French-Style Sector Signed by Louis Lennel

The arms of this brass instrument have straight edges, but the hinge is decorated with a flower. One side has double scales of chords, running from 10 to 180; of solids, running from 1 to 64; and for the specific weights of five metals, marked with their symbols. On one arm, the outer edge has a scale that runs from 4 to 24 and is labeled "Poids des Boulets." The sector is marked: Lennel à La (/) Sphére à Paris.
The other side has double scales for equal parts, running from 10 to 200; for architectural drawings, running from 1 to 64; and for the lengths of the sides of inscribed regular polygons, from 12 sides to three sides. On one arm, the outer edge has a scale running from 4 to 24 and labeled "Calibre des Pieces."
In 1774, Louis-Pierre-Florimond Lennel took over the Paris workshop operated by his teacher, Jacques Canivet, who previously had succeeded his uncle, the famous instrument maker Claude Langlois. All three men supplied telescopes to French astronomers. By 1781, Lennel called himself the official maker for France's king and the navy. He died by 1784 and was succeeded by his widow.
References: Maya Hambly, Drawing Instruments, 1580–1980 (London: Sotheby's Publications, 1988), 28; Harriet Wynter and Anthony Turner, Scientific Instruments (New York: Charles Scribner's Sons, 1975), 158; Adler Planetarium, Webster Signature Database,
Currently not on view
Object Name
date made
Lennel, Louis-Pierre Florimond
Physical Description
brass (overall material)
overall: 3.1 cm x 16.7 cm x .4 cm; 1 7/32 in x 6 9/16 in x 5/32 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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