Over a shallow hole in the
ground Dhan had constructed a smelting furnace, a clay wall
surrounded by a thicker outer wall of rock and mud, the whole girdled
with bands of sapling. It stood the height of a man's shoulders and a
pace wide, tapering to a slightly narrower diameter at he top to
concentrate the heat and reinforce the walls against collapse.
In this oven Dhan made
wrought iron by burning alternating layers of charcoal and Persian
ore, pea and nut size. Around the oven a shallow trench had been dug.
Sitting on the outer lip with his feet in the trench, he operated
bellows made from the hide of a whole goat, forcing precisely
controlled amounts of air into the glowing mass. Above the hottest
part of the fire, ore was reduced to bits of iron like drops of metal
rain. They settled through the furnace and collected at the bottom in
a blob-like mixture of charcoal, slag and iron, called the bloom.
Dhan had sealed a removal
hole with clay that he now broke away so he could drag out the bloom,
which was refined by strong hammering requiring many reheating in his
forge. Most of the iron in the ore went into slag and waste, but that
which was reduced made a very good grade of wrought iron. But it was
soft, he explained to Rob through Harsh. The bars of Indian steel,
carried from Kausambi by the elephants, were very hard. He melted
several of these in a crucible and then quenched in fire. After
cooling, the steel was extremely brittle and he shattered it and
stacked it on pieces of the wrought iron.
Now, sweating among his
anvils, tongs, chisels, punches, and hammers, the skinny Indian
displayed biceps like serpents as he wedded the soft and hard metals.
He forge-welded multiple layers of iron and steel, hammering as if
possessed, twisting and cutting, overlapping, fording the sheet and
hammering again and again , mixing his metals like a potter wedging
clay or a woman kneading bread.
Watching him, Rob knew he
could never learn the complexities, the variables needing subtle
skills passed down long generations of Indian smiths, but he gained
an understanding of the process through asking innumerable questions.
From the book “The
physician” by Noah Gordon.