Newcomen's Atmospheric Engine

The first practical steam engine was built not to drive factories but to drain mines. In 1712 Thomas Newcomen, an ironmonger from Dartmouth, installed an engine near Dudley in the West Midlands. It worked by filling a cylinder with steam and then spraying in cold water; the steam condensed, creating a partial vacuum, and the pressure of the atmosphere pushed the piston down, rocking a great beam that worked a pump.

Newcomen's engine was huge, slow and wasteful of fuel, because the cylinder was heated and cooled with every stroke. That inefficiency mattered little at coal mines, where unsellable small coal was almost free, which is why the engines spread across British coalfields and beyond. Hundreds were built during the 18th century. The Newcomen engine shows how a technology can succeed when it fits local conditions, even if it looks crude to later eyes.