Olaus magnus and the 'compass' on Hvitsark

Three textual works by Olaus Magnus (1490-1557) hold the key to the 'compas s' on his invented island of Hvitsark, shown on his 1539 Carta marina. Alth ough Olaus had little general understanding of the magnetic compass or of n avigation in the Far North, he evidently did not intend the navigational de vice he drew on Hvitsark to represent a magnetic compass, but a sundial. Hi s muddled ideas about the relationship between 12 wind-directions and direc tion-finding at sea by means of such a dial appear related to his second-ha nd information about a gnomonic navigational device used by the medieval No rse.