=81. Introduction of the compass, and of navigators’ directories.=—The first documentary evidence of acquaintance with the compass in the West dates from a little before 1200; and within fifty years we find it mentioned in nearly a dozen different places, both in the North and South of Europe. It has been suggested that Mediterranean sailors may have been the first to learn of the compass, from the Arabs, but that they could not use it in its early form of a magnetized needle floated on water by a rush or cork, because of the choppy seas; later the needle was balanced, as at present, on a point. In 1300 the compass was in general use. It is possible to exaggerate its importance as a cause of the great maritime explorations; for without it the Northmen had made their distant expeditions to the North and West, and with it the Portuguese crept along the west coast of Africa only slowly and timidly for a considerable period. As a means to regular navigation, however, it was indispensable; and the great extension of commercial voyages in the last two centuries of the Middle Ages is inconceivable without it. Medieval types of “sailing directions” now came into use; these were manuals telling the sailor about the coast, the tides, the bottom, and other features of the route he was to traverse. One of them, written probably before 1400, covered the whole West of Europe from Spain to the mouth of the Finnish gulf, enabling the mariner who was provided with a compass (used for determining the time of tides) to navigate the coast with a fair degree of safety. =82. Limits of early trading voyages.=—Maritime voyages were made to suit the conditions of the time. In the first part of the period under discussion (say before 1300), they were attempted only for short distances and in the part of the year when severe storms were rare. “To sail after Martinmas (November 11) is to tempt God,” writes an old chronicler; and in the early days of the Hanseatic League there was a regulation by which ships were not to sail after November 11, and were to be in port if possible before that time. Some time afterwards an amendment was adopted which allowed ships laden with beer, herrings, or dried cod to sail as late as December 6, because the cargo was perishable or was needed for the Lenten market. The extent of the voyage was at first short. The sailors of Bordeaux would go as far as the coast of Brittany and Normandy; the Normans would go as far as England and Flanders; and so the chain of voyages was kept up.