The 18th century also witnessed a revolution in technology associated with iron production. Although this industry did not challenge the dominance of the cotton industry, the advances in the smelting and refining processes nonetheless did increase significantly the supply of cheaper and more usable metal for a variety of purposes during the Industrial Revolution. The developments in the chemical process of metallurgy moved steadily to reduce iron in a compound form to a pure form. Carbon and heat are required to achieve this end. Before the 18th century, charcoal derived from wood had been used for smelting iron ore. However, the cost of wood had risen as Great Britain’s forests became depleted. Great Britain’s seemingly endless abundance of coal had been used for heating since the late Middle Ages, but the coke produced from coal had more impurities than the charcoal produced from wood. In 1709 Abraham Darby succeeded in coke-blasting iron and began a long but steady process that resulted in the production of wrought iron that had the malleable characteristics needed in industry. For six decades after Darby’s breakthrough, coke supplies increased as blast furnace design improved and size increased until steam blasting brought the process to new heights. Because blast furnaces produced pig iron, which was too hard to work with, it had to be poured into cast molds to remove the remaining impurities. For decades this process required the heating and reheating of the metal in charcoal fires to get a workable metal, a long and expensive endeavor. Beginning in the 1730s new innovations appeared that ultimately led to Henry Cort’s famous ‘‘puddling’’ process in 1784 that saved fuel and ensured faster production and increased the amount of usable iron by nearly 1,500%. Steam power rolled the metal and quickly replaced hammering by hand. As a result, Great Britain’s production of pig iron accelerated: 25,000 tons by the 1720s, 125,000 tons by 1740, 250,000 tons by 1804, 581,000 tons by 1825, and 2,700,000 tons by 1852.13 Similar to the developments in the cotton industry, the iron industry had its own fits and starts with small gains at times and significant leaps at others. The dramatic shift of fortunes can be demonstrated in other ways. In the middle of the 18th century, Great Britain imported double the iron it produced, but by the end of the Napoleonic Wars the nation exported five times the amount imported. Britain’s exports of iron ore increased twenty times from 57,000 tons in 1814 to more than one million tons in 1852.
The improvement in iron production stimulated developments in other industries such as beer-brewing, pottery making, glazing, printing, commercial baking, but most significantly mining. The growing demand for coal to be used in the smelting process created the need to mine deeper as the surface veins became depleted. The penetration of the water table then led to the problem of flooding of the mine shafts similar to the dilemma faced by the tin, copper, and lead mines in the early 18th century. The first response was the use of horsepower to raise the water in buckets. In Warwickshire some 500 horses did the labor, but fatigue and costs associated with food and housing the animals were a consideration. Captain Thomas Savery introduced steam power to solve the problem with his device known as the ‘‘Miner’s Friend’’ in the late 18th century. His engine was a tireless machine that operated more efficiently than the horses and used a small amount of the bountiful supply of coal being mined. His original patent lasted 14 years. Once it expired, a number of inventors seized the opportunity to improve his original machine as the depletion of surface veins forced mine shafts to go deeper for mineral resources. In 1800 Great Britain used 11 million tons of coal annually. That amount increased two times by 1830, doubled again by 1845, and doubled once more by 1870. The mining industry also employed iron rails to facilitate carts of coal pulled by horses or people and after 1800 by steam powered devices. In addition, iron producers shared knowledge with textile and other industries regarding machine building and steam power. Again, a lag occurred. For example, a dozen years passed from the appearance of Watt’s steam engine in the mid-1760s to the construction of more standardized cylinders for the engine.
World History
