The early bearing-dial contains a lot of information on the reverse. The vikings showed directions towards land and away from land on the front and reverse sides based on a special meridian.

Details relating to navigation and mapmaking by the early bearing-dial on the left and a later bearing-dial on the right are supported by information from the Vinland sagas. The later bearing-dial is turned 30 degrees related to the early one. Pls. read my articles and abstracts of the functions linked on the main site.

Figur 8: Map markings on later bearing-dial.