We may suppose that a knowledge of iron would spread rapidly. The knowledge of metallurgy necessary for the production of bronze was at this time widely disseminated. It would require, therefore, but a hint to start them in experiments. In the dissemination of this knowledge, commerce, of course, played a most important part. Whenever the early Greek and Roman writers have occasion to mention the arms of the less civilized tribes of Europe, we learn they were of iron. This shows that at a very early time this knowledge had spread all over Europe.7
It is scarcely necessary to remark that the use of iron would not drive out the use of bronze. That would still be used for many purposes; and even stone would continue in use, at least for some purposes. At the battle of Marathon, arrow-heads and lances of stone were largely used. We can easily understand how, by one of a number of causes, some rude tribes, yet unacquainted with the use of metal, would come to occupy the site of some settlement, the inhabitants of which had been in the Bronze or Iron Age. This actually happened at ancient Troy, where the remains of a stone-using folk have been found above those of a people using metal. This, though an exception to the general rule, need give us no surprise.
Iron manufacture at the present day, is one of our great industries. In its present form it is the final development of an industry whose first unfoldings we have now to glance at. That the first process man employed to procure iron should have been very rude, is what we would expect. Some of the partially civilized tribes of to-day may give us an insight into the process employed. We are told that in Tartary each native makes the iron he needs, just as every household would make its own bread. The furnace is a very small affair, not holding more than three pounds of ore. This is filled with ore and charcoal. The bellows are used, and after the charcoal is all burned out, the result is a small piece of spongy iron, which needs only repeated heating and hammering to be made serviceable.8 Primitive furnaces, on a somewhat larger scale, have been discovered in Switzerland. Here the excavation was made in the side of a hill, and a rude, dome-shaped chimney built over it.