Paulus_Swaen
Very fine marine parallel rulers in brass. The parallel ruler is the oldest and most traditional way to measure and trace routes and bearings. The principle is simple: the ruler is placed on the road to be measured and then, like a pantograph, the other part of the ruler is placed on one of the declination roses on the map to determine the angle. They are, essentially, two straight-edges hinged so that they maintain the same angle. By alternating the moving edge, and securely holding down the no...
£1.128