Brass cylinder with 5 x 1" (12.7 x 2.5cm) aperture cut in its side. A magnifier dia. 1" (2.5cm) is mounted above the aperture on two parallel brass rods which allow it to be moved over the length of the aperture. Inside the cylinder is a glazed map of England and East coast of Ireland, which can be rotated by a brass milled knob at base and which is viewed through the aperture and magnifier.