It is difficult to conceive that such an international commerce can have existed at such a remote period, and the difficulty is increased by the fact that in Europe, where we can pretty well trace the passage from the neolithic into the bronze period, bronze does not seem to have been known until some 2000 or 3000 years later, when the Phoenicians had migrated to the eastern shore of the Mediterranean, and extended their commerce and navigation far and wide over its northern coasts and islands; and at a still later period, when the Etruscans had established themselves in Italy and exported the products of the Tuscan tin mines by trade routes over the Rhætian Alps. It is even doubtful whether there was any knowledge of metals in Europe prior to the Phoenician period, as the Aryan names for gold, silver, copper, tin, and iron are borrowed from foreign sources; and have no common origin in any ancestral language of the Aryan races before they were differentiated into Greek, Latin, Teutonic, Celtic, and Slavic. Copper seems to have been the first metal known, and there are traces of a copper age prior to that of bronze in some of the older neolithic lake villages of Switzerland and Italy, and in very old tombs and dolmens in Hungary, France, and the south-west of Spain. But these copper implements are very few and far between, they are evidently modelled in the prior forms of polished stone, and must have been superseded after a very short time by the invention or importation of bronze, which, as already stated, implies a supply of tin, and a common knowledge of the art of alloying copper with it in the same uniform proportion which gives the best result. But in the historic records and remains of Egypt and Chaldæa, which go so much further back, bronze had evidently been long known when history commences. The Accadian name for tin, _Id-Kasdaru_, is the oldest known, and reappears in the Sanscrit _Kastira_, the Assyrian _Kasugeteira_, and the Greek _Kassiteros_. The oldest known name for copper is the Accadian _urud_ or _urudu_, which singularly enough is preserved in the Basque _urraida_, while _as rauta_ it reappears as the name for iron in Finnish, and as _ruda_ for metal generally in Old Slavonic. In Semitic Babylonian, copper is _eru_, which confirms the induction that the metal was unknown to the primitive Semites, and adopted by them from the previously existing Accadian civilization. We are thus driven back by every line of evidence to the conclusion that Egypt and Chaldæa were in the full, bronze age, and had left the stone period far behind them, long before the primitive stocks of the more modern Aryan and Semitic populations of Europe and Western Asia had emerged from the neolithic stage, and for an unknown period before the definite date when their history commences, certainly not less than 7000 years ago.