Early gunner’s sector by Chapotot circa 1700

Early gunner’s sector by Chapotot circa 1700




Country of manufacture


Categories: Calculating, Drawing Instruments


An early gunner’s sector by Chapotot (active ca. 1670-1700) dating to the end of the 1600s. Features several scales including Demi pied de roi (half a king’s foot), Demi diam des boulets (half diameter of bullets), Demi diam des calibres (half diameter of calibers, or the bore of gun barrels), chords, equal parts, and polygons. This small but very fine calculating instrument could have been used for measuring the diameter of gun barrels and ammunition in the field which was necessary to ensure proper firing before standardization of such weaponry became common.

Louis Chapotot began working in 1670 in Paris. Chapotot apprenticed with Guillaume Ménard in 1670 and was then appointed Master of the Corporation des Fondeurs. Chapotot and his son Jean (active. 1676 – 1721) were highly regarded instrument makers who occupied premises “sur Le Quay de l’Horloge, Ile de La Cite, a La Sphere, Paris” according to their trade card, see final image. Surviving instruments show their elite clientele included the Russian Tsar, Peter the Great and the court of the Qing Emperor.

A very similar sector by Chapotot, though not as specifically engraved for artillery, can be found in the Adler Planetarium collection:


Surface has some scratches and areas of minor discoloration but engraving and decorative details are crisp.

16.5 cm open, 8.3 cm closed

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