A lacquered brass theodolite signed Troughton & Simms LONDON, with graduated bubble level over telescope, with rack and pinion focusing, dust cap, in cradle over vertical half circle, with silvered scale and vernier, supported by twin A frame mounts, over horizontal circle with compass box, edge bar needle and cap, bubble and cross bubble, twin vernier scales with magnifier, tangent screw and clamp, on four screw tripod mount, 19th Century - 10¼in high