Coke smelting is one of the famous inventions of the Industrial Revolution and had an enormous long-run impact, for it was essential for the production of cheap iron, which, in turn, was required for the railroad, steamships and the mechanization of industry. Abraham Darby's success in 1709 was a macro-invention that radically changed factor proportions as coke displaced charcoal in the blast furnace. The macro-invention was followed by a century and a half of improvements in which productivity rose substantially. Technical change was far more neutral than the original invention: between 1709 and 1850, all of the inputs were saved with the greatest economies occurring in coal and labour. Many of these advances were due to local learning.