Steam Power and the Steam Engine in the Industrial Revolution
The steam engine was the single most important invention of the First Industrial Revolution. By providing a cheap, reliable, and flexible source of power, the steam engine reshaped industry, transportation, and mining, and it made possible the new factory system, the railway, and the steamship. The pages below trace the development of the engine from its origins in the coal mines of early eighteenth-century England to its mature form in the early nineteenth century, and link to detailed articles about the engineers, the engines, and the applications that defined the age of steam.
The Problem the Engine Solved
The story of the steam engine begins with coal. By the early eighteenth century, the coal mines of Britain were being dug deeper, and the deeper mines were increasingly threatened by flooding. The traditional methods of pumping water, using horse-powered pumps or hand-worked buckets, were unable to keep up with the inflow, and many deeper seams of coal had to be abandoned. The economic loss was significant, since coal was in growing demand for both domestic heating and industry.
A series of inventors, beginning with Thomas Savery and culminating in Thomas Newcomen, tried to solve the problem by using steam to drive pumps. The first commercially successful steam engine was the Newcomen atmospheric engine, introduced in 1712. The Newcomen engine used steam to fill a cylinder and then condensed the steam with a jet of cold water, creating a partial vacuum that allowed atmospheric pressure to push a piston down. The piston was connected by a rocking beam to a pump rod, which lifted water out of the mine.
The Newcomen engine was a major improvement over the horse pumps it replaced, and more than a hundred Newcomen engines were built in Britain and abroad over the next half century. But the engine was inefficient, burning huge quantities of coal to produce relatively little work, and it was only economical in coal-mining regions where coal was cheap. The need for a more efficient engine was clear, and it was the problem that James Watt would eventually solve.
Watt’s Breakthrough
The decisive breakthrough came in the 1760s with the work of James Watt, a Scottish instrument maker who was repairing a model Newcomen engine at the University of Glasgow. Watt realized that the major source of waste in the Newcomen engine was the repeated heating and cooling of the cylinder, and his solution, patented in 1769, was the separate condenser, a vessel kept cool by a surrounding water bath while the cylinder remained hot. The result was a dramatic reduction in fuel consumption, and the Watt engine quickly displaced the Newcomen in coal mines and other applications.
Watt continued to improve his engine over the following decades, adding features such as the double-acting cylinder, the centrifugal governor, the pressure gauge, and the sun-and-planet gear, which converted the up-and-down motion of the piston into rotary motion suitable for driving factory machinery. By the 1790s, the Watt engine was the dominant source of industrial power in Britain, and it had begun to be used in cotton mills, flour mills, ironworks, and a wide range of other industries.
The High-Pressure Engine
Watt’s engines were low-pressure engines, working at pressures of only a few pounds per square inch. A different line of development produced the high-pressure engine, in which steam was used at much higher pressures. The Cornish engineer Richard Trevithick was the leading figure in this development, and he built the first high-pressure engines in the early 1800s.
The high-pressure engine was more compact and lighter than the low-pressure engine, and it was particularly suitable for mobile applications, where the weight of the engine was a major constraint. Trevithick built the first steam locomotive to run on rails in 1804, and the high-pressure engine was the basis of most subsequent locomotive and traction engine designs. The high-pressure engine also made the steamship more efficient, and it was the basis of the marine engines that drove the great expansion of ocean shipping in the nineteenth century.
The Engine in Industry
By 1840, the steam engine had become the universal power source of British industry. A typical cotton mill might contain a single large steam engine driving hundreds of spindles through a system of belts and shafts. The cost of steam power had fallen to a small fraction of what it had been in the Newcomen era, and steam engines were being built in large numbers by specialist firms in Manchester, Leeds, Birmingham, and other industrial centers.
The spread of the steam engine had several important consequences. It freed industry from dependence on water power, allowing factories to be built in cities and on coalfields, rather than along rivers. It allowed industry to be concentrated in large factories, since the steam engine could provide enough power to drive many machines. And it created a huge demand for coal, since the engines burned large quantities of fuel, and this demand in turn stimulated the growth of the coal-mining industry.
The Engine in Transportation
Perhaps the most visible application of the steam engine was in transport. The development of the steam locomotive by engineers such as Richard Trevithick and George and Robert Stephenson transformed overland transport in the nineteenth century. The opening of the Stockton and Darlington Railway in 1825 and the Liverpool and Manchester Railway in 1830 marked the beginning of the railway age, and within a generation railways had spread across Britain, Europe, and North America.
The steamship, made practical by improvements in marine engines by figures such as Charles Napier and Isambard Kingdom Brunel, revolutionized water transport. Steamships gradually replaced sailing ships on the major trade routes, allowing goods and passengers to move with a speed and reliability that had never been possible before. The combination of railways and steamships, both powered by steam, created a global transport network that bound the world economy together in a way that had never before been possible.
The Engine in Mining
The steam engine was first developed for use in coal mines, and mining remained one of its most important applications throughout the First Industrial Revolution. The deep coal mines of the Northeast, the Midlands, South Wales, and Scotland were heavily dependent on steam engines for pumping out water, winding up coal and miners, and ventilating the underground workings. The Cornish tin and copper mines, which were among the deepest in the world, became famous for the high-pressure steam engines that kept them operational.
The development of the steam engine was therefore intimately connected with the development of the mining industry, and the availability of cheap coal was a precondition for the spread of the steam engine throughout the rest of the economy. The article on coal and iron ore describes the central role of these resources in the Industrial Revolution.
The Wider Impact
The development of the steam engine had effects that went far beyond industry and transport. The availability of cheap power allowed the development of new manufacturing processes, including the production of cheap paper, the printing of books and newspapers, and the manufacture of machine tools. The growth of the steam-powered factory system created a new industrial working class, with new patterns of work, new forms of organization, and new political demands. The article on the factory system and urbanization describes these changes.
The steam engine also had profound environmental consequences. The burning of coal released large quantities of carbon dioxide into the atmosphere, and the coal smoke produced by the engines and the factories they powered polluted the air of the new industrial cities. The long-term environmental effects of the steam engine are still being felt today, and the debate over climate change is in many ways a debate about the legacy of the energy choices made by the first generation of steam-engine builders.
The most important open scholarly debate about the steam engine is the Cornish-versus-Watt debate: how should we read the late-19th-century Cornish engine-efficiency data, in which engines in the Cornish tin and copper mines achieved duty figures (horse-power-hours per hundredweight of coal) that were substantially better than any Boulton and Watt engine of 1800? The standard account, going back to Samuel Smiles and given its modern form in schoolbook accounts, is that the Watt separate-condenser patent of 1769 was the breakthrough on which the Industrial Revolution turned, and that the Cornish engineers of the 1810s and 1820s were running engines on the same basic Watt design. The revisionist account, developed in the work of Richard Hills (Power in the Industrial Revolution, 1970) and given a quantitative form in John Kanefsky and John Robey’s “Steam Engines in 18th-Century Britain” (Technology and Culture 21, 1980), is that the Cornish duty figures of the 1820s were substantially better than the Boulton and Watt engines of 1800 could have achieved, and that a substantial fraction of the fuel efficiency usually credited to Watt actually came from the work of the Cornish engineers, who improved boiler design, raised working pressures, and used expansion in the cylinder. The unresolved question is how to read the Watt legend in light of the Cornish data, and the answer the modern literature tends toward is: Watt’s separate condenser was the theoretical breakthrough, but the working steam engine of 1830 was the work of a community of engineers that included Watt, the Boulton and Watt shop in Birmingham, and the Cornish engineers who pushed duty figures to the thermodynamic limit. The interesting current question, raised in the recent literature on the history of energy efficiency, is whether the same community-of-engineers story is the right way to read the 20th-century gas turbine, the 21st-century combined-cycle power plant, and the modern lithium-ion battery.