Istwa Nou

In the first centuries CE African smiths circulated a new body of forging technique, spreading it along the rivers of the Congo basin. Jan Vansina called the result Africa's second iron age. One product shows what the technique could do. The flange welded double bell was made by forging four flat sheets of iron, reheating each one, hammering it over a rounded form until it curved into a half bell with a flat flange standing out all round the curve, then welding the flanges of each pair together in the fire, then forging a curved iron handle and welding that to the tops of both bells so the instrument held as one piece. Every stage demands temperature control, symmetry and a sound weld. Smiths in the equatorial rainforest were still producing these bells in the nineteenth century, eighteen hundred years after the method appeared, which says the knowledge was taught, held and handed down without interruption across that whole span.