Measures of length and contents often differed much from one another, although they might be similarly named, and it would require very complicated comparative tables approximately to fix their value. The _pied de roi_ was from ten to twelve inches, and was the least varying measure. The fathom differed much in different parts, and in the attempt to determine the relations between the innumerable measures of contents which we find recorded--a knowledge of which must have been necessary for the commerce of the period--we are stopped by a labyrinth of incomprehensible calculations, which it is impossible to determine with any degree of certainty.
The weights were more uniform and less uncertain. The pound was everywhere in use, but it was not everywhere of the same standard (Fig. 201). For instance, at Paris it weighed sixteen ounces, whereas at Lyons it only weighed fourteen; and in weighing silk fifteen ounces to the pound was the rule. At Toulouse and in Upper Languedoc the pound was only thirteen and a half ounces; at Marseilles, thirteen ounces; and at other places it even fell to twelve ounces. There was in Paris a public scale called _poids du roi_; but this scale, though a most important means of revenue, was a great hindrance to retail trade.
In spite of these petty and irritating impediments, the commerce of France extended throughout the whole world.
[Illustration: Fig. 197.--View of Lubeck and its Harbour (Sixteenth Century).--From a Copper-plate in the Work of P. Bertius, "Commentaria Rerum Germanicarum," in 4to: Amsterdam, 1616.]
The compass--known in Italy as early as the twelfth century, but little used until the fourteenth--enabled the mercantile navy to discover new routes, and it was thus that true maritime commerce may be said regularly to have begun. The sailors of the Mediterranean, with the help of this little instrument, dared to pass the Straits of Gibraltar, and to venture on the ocean. From that moment commercial intercourse, which had previously only existed by land, and that with great difficulty, was permanently established between the northern and southern harbours of Europe.
Flanders was the central port for merchant vessels, which arrived in great numbers from the Mediterranean, and Bruges became the principal depôt. The Teutonic league, the origin of which dates from the thirteenth century, and which formed the most powerful confederacy recorded in history, also sent innumerable vessels from its harbours of Lubeck (Fig. 197) and Hamburg. These carried the merchandise of the northern countries into Flanders, and this rich province, which excelled in every branch of industry, and especially in those relating to metals and weaving, became the great market of Europe (Fig. 198).