The Arabs and the compass
Through an apparently small thing the Arabs possibly exercised more than in anything else a transforming influence upon the navigation, geography and cartography of Europe; for it was probably they who first brought to Europe the knowledge of the magnetic needle as a guide. We know that the Chinese were acquainted with it, at any rate in the second century A.D., and used it for a kind of compass for overland journeys. Whether they also used it at sea we do not know, but it may readily be supposed that they did. That the Arabs through their direct commercial intercourse with the Chinese became acquainted with this discovery at an early date seems probable; but curiously enough we hear nothing of it in Arabic literature before the thirteenth century. As the Arabs and Turks after that date used the Italian word “bossolo” for compass (bussol), it has been thought that they may have derived their knowledge of it, not from China, but from Italy; but it seems more reasonable to suppose that, while they had their first knowledge of the magnetic needle from China, they obtained an improved form of the compass from Italy, and with it the Italian word.
COMPASS-CHARTS
Oldest authorities on the compass in Europe
We do not know how early the magnetic needle’s property of pointing to the north became known in Europe and used for finding the way at sea. The first mention of it is found at the close of the twelfth century in the works of the Englishman Alexander Neckam, professor in Paris about 1180-1190, and of the troubadour Guyot de Provins from Languedoc. The latter, in a satirical poem of about 1190, wishes the Pope would imitate the immutable trustworthiness of the polar star by showing the steadiness of the heavenly guide; for sailors come and go by this star, which they are always able to find, even in fog and darkness, by a needle rubbed with the ugly brown lodestone; stuck in a straw and laid upon water, the needle points unfailingly to the north star. As late as in 1258 Dante’s teacher, Brunetto Latini, saw as a curiosity in the possession of Roger Bacon at Oxford a large and ugly lodestone, which was able to confer on an iron needle the mysterious power of pointing to the star; but he thinks that it cannot be of any use, for ship-masters would not steer by it, nor would sailors venture to sea with an instrument which was so like an invention of the devil. As always when the progress of humanity is at stake, orthodoxy and religious prejudice raises its head. It is certain that the use of the compass-needle must have been known in the Mediterranean at the beginning of the thirteenth century, and probably even in the twelfth. It has been alleged that the compass was known long before that time, even in the eleventh and tenth centuries; but no proof of this has been found, and it does not appear very probable.[209] How early the compass, or lodestone, was known in the North is uncertain. We only know that when the Hauksbók was written, at the beginning of the fourteenth century, it was at any rate known in Iceland (cf. vol. i. p. 248); but it may of course have been known before that time, and it does not appear that any long time elapsed between the instrument’s being known in the Mediterranean and its reaching the Scandinavians.
Oldest sea-charts
When the compass came into general use on Italian ships in the thirteenth century, it naturally led to the development of an entirely new type of map, the Italian sea-charts or compass-charts, which were to be of fundamental importance to all future cartography. The mediæval maps of the world already mentioned were learned representations which were of no practical use to the navigator. The Greeks had drawn land-maps which were also of no great use at sea, and we do not know that they had sea-charts. On the other hand sailing-books (“peripli”), which gave directions for coasting voyages, were in use far back in antiquity. In the Middle Ages sailing-books, called “portolani,” which gave information about harbours, distances, etc., were an important aid to the navigator, especially in the Mediterranean. It was the Italians before all others who at that period developed navigation. When coasting was to some extent replaced by sailing in open sea, after the compass came into use, sea-charts became a necessary adjunct to the written sailing-books or portolani. How early they began to be developed is unknown; we only know that charts were in use on Italian ships in the latter half of the thirteenth century;[210] and we must suppose that they were employed long before that time. Whether, as some have maintained, there was a connection between these charts and the maps of the Greeks is doubtful, though there may indeed have been an indirect connection through the Arabs, among whom Edrisi, for instance, seems perhaps to have exercised some influence. But in any case it is certain that the Italians of the Middle Ages were not acquainted with Greek cartography, and this may in a way be regarded as an advantage; for they were thus obliged to invent their own mode of representation. For Greek thought the chief thing was to find the best expression for the system of the world and the “œcumene,” to solve problems such as the reduction of a spherical to a plane surface by projection, etc.; while the sense of accurate detail was less prominent. The Italian sailor and cartographer went straight to nature, unhindered by theory, and to him it appeared a matter of course to set down on the map coasts and islands as accurately as possible according to the course sailed and the distance, without reflecting that sea and land form a spherical surface.
The Italian sea-charts seem especially to have been developed in the republics of northern Italy, Genoa and Pisa, and to some extent Venice. Later the Catalans of the Balearic Isles and of Spain (Barcelona and Valencia) also learned the art, probably from Genoa. The charts have been justly admired for their correct and detailed representation of the coasts known to the Italians and the seamen of the Mediterranean; the world had never before produced any parallel to such a representation. It shows that the sailors of that time were masters in the use of their compass,[211] and in making up their reckoning. The remarkable thing is that the first known compass-charts, of the beginning of the fourteenth century, were already of so perfect a form that there was little to add to or improve in them in later times. It looks as though this type of chart suddenly sprang forth in full perfection, like Athene from the brain of Zeus, without our knowing of any forerunner; it held the field with its representation of the coasts of the Black Sea, the Mediterranean, and Western Europe almost unaltered through three centuries. There is something puzzling in that. We must suppose in any case that these charts were developed through many smaller special charts throughout the whole of the thirteenth century, but even that seems a short period for the development of a representation so complete as this, which thenceforward became almost stereotyped. It is principally the coasts that are represented, with many names, while inland there are comparatively few, which of course is natural in sea-charts.
Extent of the compass-charts
As Italian trade did not extend farther north than Flanders and England (from whence came wool), it is also characteristic of the compass-charts that their detailed representation of the coast extends to the south of England and to Sluis in Flanders, and to the mouth of the Scheldt. Farther than this the Italian ships did not sail; beyond this boundary began the commercial domain of the Hanseatic League. The delineation on the compass-charts of the greater part of Ireland, northern England, Scotland, the north coast of Germany, Denmark, the Baltic and Scandinavia has an entirely different character from that of the more southern coasts. The coast-lines are there evidently drawn in a formal way, and more or less hypothetically; the names (chiefly those of a few ports, bishops’ sees and islands) are also strikingly few. It is clearly seen that these coasts cannot have been drawn from actual compass courses and reckonings; they are sketches based on second- or third-hand information. For this reason too the shape of the northern countries may be subject to considerable variation in the different types of compass-charts.