Gioja, of Amalfi, in the beginning of the fourteenth century.
When once the mariner's compass had come into general use, and its indications observed bymaster mariners in their voyages, a much more practical method was at hand for determining the relative positions of the different lands. Hitherto geographers (i.e., mainly Greeks and Arabs) had had to depend for fixing relative positions on the vague statements in the itineraries of merchants and soldiers; but now, with the aid of the compass, it was not difficult to determine the relative position of one point to another, while all the windings of a road could be fixed down on paper without much difficulty. Consequently, while the learned monks were content with the mixture of myth and fable which we have seen to have formed the basis of their maps of the world, the seamen of the Mediterranean were gradually building up charts of that sea and the neighbouring lands which varied but little from the true position. A chart of this kind was called a Portulano, as giving information of the best routes from port to port, and Baron Nordenskiold has recently shown how all these portulani are derived from a single Catalan map which has been lost, but must have been compiled between 1266 and 1291. And yet there were some of the learned who were not above taking instruction from the practical knowledge of the seamen. In 1339, one Angelico Dulcert, of Majorca, made an elaborate map of the world on the principle of the portulano, giving the coast line—at least of the Mediterranean—with remarkable accuracy. A little later, in 1375, a Jew of the same island, named Cresquez, made an improvement on this by intro-
