Bidspirit auction | Large-Format Prismatic Surveying Compass W/Case

Large-Format Prismatic Surveying Compass W/Case - A high-precision, professional-grade Prismatic Surveying Compass (Schmalcalder-type), likely of British or American manufacture circa 1890-1920 This large-format instrument was designed for topographical mapping, civil engineering, or military reconnaissance where high-accuracy bearings were required. Optics: Features a hinged prism assembly with an integrated magnifying lens and a tinted green glass sunshade for use in high-glare environments. Dial: High-visibility silvered brass or aluminum dial with finely engraved degree markings, allowing for simultaneous sighting and reading of the compass card. Mechanics: Fully functional needle/transit lock mechanism, which safely lifts the compass card off the jewel pivot to prevent wear during transport. Construction: Heavy brass housing with a folding vertical sight vane and original glass. Case: Housed in its original ”teardrop” shaped leather field case. The case is stamped ”No. 4”, suggesting it was part of a numbered professional or military survey set. Condition Report: The instrument is in excellent mechanical condition. The needle lock is present and functioning properly; the dial rotates freely without ”drag.” The brass shows a natural aged patina, and the leather case remains supple with original stitching intact. No manufacturer's marks present, characteristic of private-label trade instruments of the era. Chips in glass edges in two spots. Small glass chips trapped inside compass. Please see photos for condition. Dimensions: 5.25” W x 6.75” H x 1.75” D (in case) . From the Dale Beeks collection.