Antique French brass gunnery sector rule / proportional compass, signed Langlois and Paris. Measures approx. 6.5" long when closed. Engraved brass mathematical/scientific instrument with decorative floral hinge and multiple engraved calculation scales on both sides.

Visible scale labels include Les Cordes, Les Solides, Les Métaux, Les Parties Égales, Les Plans, Les Poligones / Polygones, and other period mathematical/gunnery measurement scales. This type of sector was used with dividers for proportioning, geometry, drafting, surveying, and gunnery-related calculations before modern slide rules.

Condition is antique estate-found condition with tarnish, oxidation, spotting, scratches, edge wear, and age-related surface wear throughout. Some engraved markings are faint from age/use, but many labels and scales remain visible. Hinge opens and closes. I have not cleaned or polished the piece. Selling as an antique collectible/scientific instrument, not as a calibrated working tool.

No case, dividers, or accessories included. Please review all photos closely for exact condition, markings, and included item.