James Watt

Born on 19 January 1736 in Greenock, Scotland, James Watt was a scientist and inventor whose steam engine helped fuel the Industrial Revolution. Watt did not invent the first steam engine, but he created an efficient engine that quickly boosted the output of a variety of industries. The Watt engine’s defining component was the condenser—a dedicated chamber for converting steam into liquid water so that the cylinder didn’t have to be repeatedly heated and cooled. Watt teamed with John Roebuck to build the engine and patented it in 1769; he tinkered with and upgraded his engine many times over the next few decades. In his honor the unit of power in the International System of Units is called the watt. (Photo credit: AIP Emilio Segrè Visual Archives, E. Scott Barr Collection)

Date in History: 19 January 1736