Octant, circa 1840

octant

Octant, ebony frame, reinforced index arm, maker unknown, with inlaid elephant ivory scale, vernier, and unengraved nameplate in brace. Scale graduated from -2 to +100 deg. With brass tangent screw, index mirror, horizon glass, 3 shades, and sight vane with triple peep. Inlaid plate missing from reverse. Threaded pencil hole in brace. Radius from pivot to center of scale 9 1/2". Dated ca. 1840.