The atmospheric engine was invented by Thomas Newcomen in 1712, and is often referred to as the Newcomen fire engine (see below) or simply as a Newcomen engine. The engine was operated by condensing steam drawn into the cylinder, thereby creating a partial vacuum which allowed the atmospheric pressure to push the piston into the cylinder. It was historically significant as the first practical device to harness steam to produce mechanical work. Newcomen engines were used throughout Britain and Europe, principally to pump water out of mines. Hundreds were constructed throughout the 18th century. James Watt's later engine design was an improved version of the Newcomen engine that roughly doubled fuel efficiency. Many atmospheric engines were converted to the Watt design, for a price which was based on a fraction of the fuel-savings. As a result, Watt is today better known than Newcomen in relation to the origin of the steam engine. Precursors Prior to Newcomen a number of small steam devices of various sorts had been made, but most were essentially novelties. Around 1600 a number...