Doubtless, it was the proceeding employed by Tubalcain, and the first metallurgists of the inhabited world.

Now that which had succeeded with the grandson of Adam, and which still yielded good results in countries rich in ore and fuel, could not but succeed with the settlers in Lincoln Island.
The coal, as well as the ore, was collected without trouble on the surface of the ground.

They first broke the ore into little pieces, and cleansed them with the hand from the impurities which soiled their surface.

Then coal and ore were arranged in heaps and in successive layers, as the charcoal-burner does with the wood which he wishes to carbonize.

In this way, under the influence of the air projected by the blowing-machine, the coal would be transformed into carbonic acid, then into oxide of carbon, its use being to reduce the oxide of iron, that is to say, to rid it of the oxygen.
Thus the engineer proceeded.