wealth of Spain. Fabulous stones are told of the richness of the silver mines worked in this region. It was natural, then, that they would seek to gain access to the famous tin region which lay beyond Lusitania, the only approach to which by sea was beset by their enemies, and the very direction of which was a secret jealously guarded by the traders of Gaddir. The statement of Pytheas now finds its full force. He found, as Publius Crassus found three centuries later, that the rich mineral regions and islands of North-Western Spain were far more accessible for the Massaliotes by a land journey across Gaul and a short sea voyage, than by the long and perilous route round by Gibraltar. His information seems to have led to no practical end. The political power of Massalia was too weak for such an enterprise, and, as we have seen above, it was not until all Gaul fell under the strong hand of Rome that the idea of Pytheas became an accomplished fact.
Having thus obtained a clear view of what was meant by Keltiké in the days of Pytheas, and having also seen reasons for regarding the tin route from Britain as passing from Corbilo on the mouth of the Loire to Narbo and Massalia, let us examine the channels by which in historical times trade passed through Gaul, and between Gaul and Britain at a later time. Transit through Gaul had great natural facilities by means of the great river-systems. Strabo (iii, 177) calls attention to the advantages thus afforded: “The whole of this region is watered by rivers, some coming down from the Alps, others from the Cevennes and Pyrenees, and part flowing into the ocean, and part into our sea. For the most they flow through plains, or through low hills, with channels between that admit of navigation; and nature has so well appointed the inter-relations of the streams that transit is possible from one sea to the other, as the merchandise has to be conveyed only for a short distance overland, and that through plains which offer no difficulty, but for the greater part of the way
