The invention of the steam engine was an important milestone in the Industrial Revolution. James Watt is often credited with its invention, but Watt only brought about―admittedly game-changing―developments in the original design. The machine became symbolic of the Industrial Revolution. Most of the early developments during the period revolved around this vital invention. Charting the Development of the Steam Engine In 1698, the most primitive form of the steam engine was patented by Thomas Savery. It was a simple machine used to pump water out of coal mines; it had no moving parts, and used up huge quantities of coal. Thomas Newcomen made improvements in this machine. He added a movable piston in the original design for the steam to displace it and perform the necessary work. The engine, however, was of no significant use even after the improvements made by Newcomen. It was only in 1763 that James Watt drastically improved this machine. The pistons used in Watt's engine could be moved to-and-fro. The most important thing about these engines was that a crankshaft was used in the conversion of the motion to circular motion. This engine consumed 75% less coal than the one made by Newcomen. Circular motion produced by the steam engine lead to the development of locomotives. These locomotives were used by industries for transportation, hastening the development of the Industrial Revolution. Working The mechanism of the steam engine is quite simple. The steam needed to run this engine is produced in a boiler outside the actual engine. The flow of steam into the engine is directed through valves. Pistons in the engine move with the help of the pressure generated by the steam. These pistons move in an oscillatory motion; a crankshaft is used in the conversion of the oscillatory motion to rotatory motion. The engines developed by Newcomen and Watt didn't make full use of the steam power. Their machines were actually powered by vacuum. The vacuum was created by the condensation of steam. The role of steam in functioning of the engine was limited up to the task of compensating for the atmospheric pressure; it helped move the piston back and forth. Richard Trevithick developed engines in which steam was forced under high pressure. The size of this model, too, was reduced to great extent, making it easy to transport the engine itself. The steam engine brought about a huge change in the industrial scene. The speed of industrial development increased many times over. Therefore, the steam engine is considered as one of the greatest inventions in history.