In the late 1800s a man named James Watt figured out a way to make steam engines operate much more efficiently . He wonted to sell his new invention . But he could not describe how powerful the amazing engines were.Watt found that a pony could do 22,000 ft-lb of work a minute. Watt thought that the average horse was as powerful as 1.5 ponies,he multiplied the power of one pony by 1.5 and called it 1 horsepower.