James Watt and the Separate Condenser

In 1763 James Watt, an instrument maker at the University of Glasgow, was asked to repair a model Newcomen engine. He realized that heating and cooling the same cylinder every stroke wasted most of the fuel. In 1765 he hit on a solution: condense the steam in a separate chamber kept cold, while the main cylinder stayed hot. He patented the idea in 1769, but turning it into a reliable engine took years and money.

The breakthrough came through partnership with Birmingham manufacturer Matthew Boulton from 1775, and from precise cylinders bored by ironmaster John Wilkinson. Boulton and Watt engines used far less coal than Newcomen's, making steam worth using where coal was expensive, such as Cornish tin mines. Watt's story shows that successful innovation usually requires not just an idea but also capital, skilled manufacturing and business organization.