These three rich tin-bearing areas were: (1) Galicia in north-western Spain, (2) the south of Brittany, especially between the estuaries of the Loire and the Vilaine, a deposit long since exhausted, and (3) the still-important deposits of southern England, in Cornwall and parts of Devon, which are believed to have been visited by the Phoenicians. Just as the gold of California brought population and civilisation to the Far West of North America long before the natural increase of eastern peoples would have led to a westward movement, so the rich tin deposits of south-western Britain, with the other metals of those favoured islands, brought merchants and navigators to what was the Far West of ancient Europe. The bold navigators who had learnt their craft in the Mediterranean Sea left its basin by the Strait of Gibraltar, and visited successively those masses of ancient rocks which project out into the ocean, and form the western extremities of Spain, France and Britain. But it was not only the sea route which was utilised, at least in later times. Perhaps so long ago as five centuries before our era a land route was organised which carried British tin to Marseilles, and thus to the Mediterranean. The great valley of the Rhone renders such a traverse of France feasible, and the passage from the valley to the Rhone to that of the Loire or of the Seine is easy. The existence of a commerce in tin thus ensured that France was early and deeply permeated by Mediterranean civilisation, for it involved the existence of high roads through her land, at a time when northern Europe generally was cut off from the civilisation of the Mediterranean. There is even reason to believe that trade in tin led to the founding of an early maritime power on the barren shores of Brittany. The trade in tin certainly did much to open the way for the future civilisation of France. Though, as we have indicated, bronze was for long of relatively great importance, yet the use of iron dates back to great antiquity. It seems to have been a rare and precious metal when the Homeric poems took shape, and for long afterwards its use was partial and limited. The fact, however, that it is very readily destroyed by rust when exposed to air and damp, makes it difficult to draw any certain conclusions from its absence in ancient remains.