They […] have made some progress in the smelting of iron ore, which is very rich in this country. They construct a blast of bamboos, and by means of a lever work three or four of their cane cylinders at a time; with these they blow on the iron ore, which is broken up into "nubblets," or small pieces, and put them on a hearth until the fire renders it soft, not melted.
Source: wiktionary