(^286) THE WEALTH AND POVERTY OF NATIONS
Another way was to remove the carbon to get wrought iron, and
then add carbon to get steel. The adding was typically done by
packing bars of wrought iron in carbon, heating and soaking, and
then hammering. The aim was to beat the composite metal in such a
way as to distribute the carbon evenly and homogenize the result—
something like kneading dough. And just as kneading produces a
more homogeneous dough by folding, pressing, and folding and
pressing again, so the best of this cementation steel was folded upon
itself, rehammered, and then again and again. The result was a
layered bar of steel; the more the layers (that is, the more the folding
and kneading), the nervier and stronger the metal. The finest
examples of this kind of work are the famous Japanese samurai
swords, which still hold their edge and gleam after five centuries.
Layered steel, invented in Europe in Nuremberg at the beginning of
the seventeenth century (Nuremberg was an old center of tool- and
instrument making), was immediately picked up by the English. The
French did not learn the technique until about 1770.
But even samurai swords cannot compare for homogeneity with
crucible steel, that is, steel heated to liquid so that the carbon
additive mixes completely. The inventor of crucible steel, in 1740,
was an English clockmaker, Benjamin Huntsman, who had an
obvious professional interest in getting better metal for springs and
files. The technique would remain a British monopoly for about
three quarters of a century—not for want of would-be imitators.
The French in particular spent mightily to learn the secret. France
was comparatively weak in steel and understandably saw this as a
serious political disability. Early in the eighteenth century that
scientific jack of all trades René Antoine de Reaumur (1683-1757),
best known for his thermometer, claimed to have found the secret of
what he himself compared to the "philosophers' stone," established a
"royal manufactory" for the purpose of turning iron into steel, and
got a generous government pension for his efforts. He failed,
because he thought the answer lay in adding sulfur and the right
salts. The role of carbon never occurred to him. He also thought
that French iron was good enough for the purpose, unlike the
British, who imported the finer Swedish iron for making steel.^15 He
should have looked around.
"This error of analysis and this 'patriotic choice' would long be
accepted in France and would aggravate the backwardness of the
national industry."^16 Others came forward subsequently and bragged
that they had made steel comparable to the English and German
nora
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