French-Style Sector Signed by Pierre Le Maire

The arms of this brass instrument have straight edges, while the hinge is decorated with a floral design. The sector is marked: P. Le Maire (/) AParis. One side has double scales of chords, running from 10 to 180; of solids, running from 1 to 60; and for the specific weights of four metals, marked with their symbols. The outer edge has a scale running from 1/4 to 60 and labeled Diamettres [sic] et Poids des Boulets (for the diameter and weight of iron shot).
The other side has double scales for equal parts, running from 10 to 200; for architectural drawings, running from 1 to 60; and for the lengths of the sides of inscribed regular polygons, from 12 sides to four sides. The outer edge has a scale that runs from 1/4 to 60 and is labeled Calibres des Pieces (for the size of iron shot, given the diameter of the barrel and the weight of the shot). This arrangement of scales is standard for sectors manufactured in France.
Pierre Le Maire (1717–1785) took over his father Jacques's workshop in the late 1730s. Large numbers of his sundials, mathematical instruments, and lodestones survive. He and his workers initially signed instruments with "le Fils," so this example was probably made after 1750. The donor received this sector from a distant relative, Gunther Mathies, who emigrated from Germany in the early 20th century and worked for the Thomaston Clock Company in Connecticut.
Reference: Adler Planetarium, Webster Signature Database,
Currently not on view
Object Name
date made
ca 1750
Le Maire, Pierre
Physical Description
brass (overall material)
overall: .3 cm x 17.5 cm x 3.1 cm; 1/8 in x 6 7/8 in x 1 7/32 in
place made
France: Île-de-France, Paris
ID Number
accession number
catalog number
Science & Mathematics
Rule, Calculating
See more items in
Medicine and Science: Mathematics
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of William H. Koch
Additional Media

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