Science & TechFact
James Watt didn't invent the steam engine.
Steam engines built by Thomas Newcomen were pumping water out of English mines from 1712. But they wasted enormous amounts of coal because the cylinder was cooled on every stroke. In 1765 Watt spotted the flaw and invented the separate condenser, cutting consumption by about three quarters. Only then did steam power become affordable for factories.
Useful: The most powerful innovation is often not the new machine but fixing its biggest weakness.
Source: en.wikipedia.org