Iron is the most useful of the metallic elements. Metallic iron in a more or less pure condition is occasionally found in nature, but this supply is very small. As Tubal Cain was an instructor in working iron, we can surmise that this metal was known before his time, and it is almost certain that Cain knew of it when he invented weights and measures in the first city of which he was the founder. The iron thus used or worked was of the kind just mentioned. The period when iron was first extracted from its ore is not known, but we know that it was known in the remotest time of the history of man, from the tools and weapons found. The earliest method of extracting iron from its ore consisted in placing lumps of ore in a fire of wood or charcoal, and, after a more or less complete reduction, the spongy metal thus formed was hammered and shaped.
The Assyrians used iron very much. Saws, knives, and other tools have been found at Nineveh. Many of these tools are much like tools of the present day. Homer refers to the forging of iron. That a rude bellows was used in the forging of iron is proved by the figures in Egyptian sculpture of more than 1500 years B. C. Pliny, about 50 A. D., describes the making of iron and steel. That they had then been experimenting in the art of tempering is evident from the fact that he claims that the result of the tempering of steel is dependent on the nature of the water used, and he explains that oil in some cases was better than water.
The best iron is manufactured in Sweden. There is found good ore, and charcoal is used in the extraction of the iron from the ore; therefore Swedish iron is the best, and makes the best steel. We have, in spite of the great improvements, still a very poor grade of iron in this country. We have “cold-short” and “hot-short” iron. Sulphur in the iron when hot makes it brittle, and phosphorus makes it brittle when cold. This explains the cause for some iron breaking when we try to form a link of hot iron, while the same iron will not break if bent cold, and vice versa.