Everyone knew this and more than one inventor grasped that one way to reduce iron ore would be to rid coal of its gases, thus converting it into coke, which enabled higher temperatures to be built up more safely.13 This was first achieved around 1709, the ironmasters who made it being Abraham Darby and his family, who managed to keep their secret for more than thirty years.14 The raw iron they produced still needed to be purified, to make it workable, but in time cast iron became, in Peter Hall’s words, the plastic of its day.
