Heron, the great inventor of Alexandria, described in detail what is thought to be the first working steam engine. He called it an aeolipile, or "wind ball". His design was a sealed caldron of water ...

Watt popularized the term in an effort to quantify the output of his innovative steam engine design. With the help of assistant John Desaguliers, Watt estimated that a horse could lift 33,000 ...