A remarkable fact is that the bronze found from the earliest monuments downwards, throughout most of the ancient world, including the dolmens, lake villages, and other prehistoric monuments in which metal begins to appear, is almost entirely of uniform composition, consisting of an alloy of 10 to 15 per cent. of tin to 85 or 90 per cent. of copper. That is for tools and weapons where great hardness was required, for objects of art and statuettes were often made of pure copper, or with a smaller alloy of tin, showing that the latter metal was too scarce and valuable to be wasted.[5] Evidently this alloy must have been discovered in some locality where tin and copper were both found, and trials could be made of the proportions which gave the best result, and the secret must have been communicated to other nations along with the tin which was necessary for the manufacture. Where could the sources have been which supplied this tin and this knowledge how to use it, to the two great civilized nations of Egypt and Chaldæa, where we can say with certainty that bronze was in common use prior to 5000 B.C.? If we exclude Britain and the extreme East, there are only two localities in which extensive remains of ancient workings for tin have been discovered; one in Georgia on the slopes of the Caucasus, and the other on the northern slope of the Hindoo-Kush in the neighbourhood of Bamian. And the knowledge both of bronze and of other metals, such as iron and gold, seems to have been universally diffused among the Turanian races who were the primitive inhabitants of Northern Asia. How could Egypt have got its tin even from the nearest known source? Consider the length of the caravan route; the number of beasts of burden required; the necessity for roads, depôts, and stations; the mountain ranges, rivers, and deserts to be traversed; such a journey is scarcely conceivable either through districts sparsely peopled and without resources, or infested by savage tribes and robbers. And yet if the tin did not come by land, it must have come for the greater part of the way by water, floating down the Euphrates or Tigris, and being shipped from Ur or Eridhu by way of the Persian Gulf and Red Sea. [5] This normal alloy does not seem to have been in general use in Egypt before the eighteenth dynasty, and the bronze of earlier periods contains less tin. But evidently a very hard alloy of copper must have been used from the earliest times, to chisel out statues of granite and diorite, and although tin was too scarce for common use, the tools for such purposes must have contained a considerable percentage of it.