'T Derde deel van 't Licht der zee-vaert, inhoudende de beschryvinghe der zeecusten van de Middelandtsche...

A detailed perspective diagram shows a scientific instrument housed in a wooden box, combining a compass and a sundial. Inside, a circular compass rose is visible, featuring a fleur-de-lis indicating North (labeled H) and cardinal/ordinal directions (labeled S and T). A semi-circular metal arch, labeled with R, Q, and P, is mounted over the box, with a decorative finial at its apex (Q). The front vertical face of the box (labeled B, C, F, G) contains a semicircular sundial scale with radiating hour lines and a gnomon at point V. A horizontal bar at the base of this face is marked with points I and K. Various other parts and points on the box are labeled with letters (A, D, L, M, N, O) corresponding to technical descriptions in the text.

rose into four times 90 degrees and place the needle underneath, just like on the compass one sails by.

Inside, on one side of the box (which we call the north side), make a sharp copper edge, exactly halfway between A and D, raised so high from the side A D that the compass may float close by it, yet freely, as H. Outside on the south side B C F G, at the bottom, make a small bar, like F G, about half an inch wide on the top side; at each end make a small hole at I and K, both equally far from the plane B C F G, and draw a straight line from one to the other, which one may see quite clearly, as I K. By the top edge, halfway between B and C, make a small peg as long as the bottom bar is wide, as L, and just as far as the line I K on that bar stands separated from the plane;