French-Style Sector Signed by Nicolas Bion

This brass instrument has rectangular arms hinged at one end. The hinge is decorated with a flower on both sides. 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. The outer edge has a scale that runs from 1/4 to 64 and is labeled poids des Boulets. The sector is marked: N. Bion (/) AParis.

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. The outer edge has a scale running from 1/4 to 64 and labeled Calibre des pieces.

Nicolas Bion (c. 1652–1733) made and sold mathematical instruments in Paris in his own shop and as royal maker for Louis XIV. He included a lengthy discussion of sectorial scales in his famous 1709 manual on the construction and use of mathematical instruments. Albert Haertlein (1895–1960), who collected this sector, graduated with a bachelor's degree in civil engineering from the Massachusetts Institute of Technology in 1918, served in the engineering corps of the U.S. Army during World War I, and taught engineering at Harvard from 1919 until 1959. He was prominent in the American Society of Civil Engineers.

References: Nicolas Bion, Traité de la construction et des principaux usages des instruments de mathematique (Paris, 1709), 29–74; "News From the Classes," Technology Review 21 (1919): 645; Albert Haertlein, Papers, HUG4444, Harvard University Archives, Cambridge, Mass.

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