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

...one might sail, one suspects firmly (whether the westeringh increases even more or not) that it would again diminish, and the needle would at last point exactly north again. That one would then call, decreasing westeringh. But since it is not our intention to describe everything that can be said about this, we shall only take that which serves the purpose:
In Amsterdam, the magnetized needle deviates from the north to the east, (which some say to have observed sharply) 9 degrees, of which 11 1/4 make a point. Therefore, compass makers here in this country place the steel or needles about three-quarters of a point east of the Fleur-de-lis, so that it would indicate the true north.
In Italy, although the needle there also does not point exactly north, but points east of it, they nevertheless place the needle exactly under the Fleur-de-lis there; perhaps because the difference is small, or possibly also because they (having their shipping mostly towards the east) want to meet with that, to some extent, the deviation that the needle has towards the west in the eastern parts of the Mediterranean Sea, to thus take a middle ground between both. Near Salines in the Island of Cyprus (as some say to have observed) the needle deviates to the west 8 or 9 degrees, which is about three-quarters of a point. If one then wanted to make the Fleur-de-lis of the compass point exactly north there, one would have to place the needle three-quarters of a point west of it, just as one places it here in this country three-quarters of a point east of it. From what is aforementioned, one can understand enough why the needle is placed differently under the compass roses at different places, to make them point exactly north.

Why the Charts original: "Pascaarten" of the Mediterranean Sea are made

without degrees of latitude.

Through this change in needle direction, it is not feasible in the charts of the Mediterranean Sea to place the lands simultaneously according to their latitudes or pole altitudes, and according to their true bearings, for this reason: It is known to everyone (experienced in the art of navigation) that two places situated at the same latitude certainly lie exactly east and west of each other, and necessarily must be sailed from one to the other with an east and west course: but that cannot happen in the Mediterranean Sea due to the change in needle direction, regardless of what compass one sails by, if the places are situated somewhat far from one another. To explain this by example: Let us take that one may sail from Malta without hindrance eastwards, to the coast of Syria, to a place at equal latitude. If one sets sail from there on a compass that points exactly north at that location, the beginning of such a voyage will be exactly east, but continuing to sail...