Where does the term "horsepower" come from?
Answer: James Watt as a Marketing Tool
History - James Watt didn’t invent the steam engine, but he did create the world’s first modern one, and developed the means of measuring its power. In the 1760s, the Scottish inventor began tinkering with an earlier version of the engine designed by Thomas Newcomen. Newcomen’s design required constant cooling down and re-heating, wasting vast amounts of energy. Watt’s innovation was to add a separate condenser, greatly improving the engine’s efficiency. A savvy salesman, Watt knew that he needed a way to market his new product. He calculated how much power a single horse working in a mill could produce over a period of time (though many scientists now believe his estimates were far too high), a figure that he dubbed “horsepower.” Using this unit of measurement, he then came up with a figure that indicated how many horses just one of his engines could replace. The sales ploy worked—we’re still using the term “horsepower” today—and his engines soon became the industry standard, leading directly to invention of the first steam locomotive in 1804.