An interesting FYI:
James Watt is said to have developed the definition of a horsepower. The
story goes that in the early days of the industrial revolution in England,
horses were used to help raise coal up from the coal mines. Usually a team
of horses were used. James Watt developed his steam engine and tried to
sell it to the coal companies to replace their horses. So, to compare
apples to apples, he measured how fast it would take a horse to lift a
weight a certain distance, and then he compared it to how fast his steam
engine could lift the same weight the same distance. That way, he could say
that his steam engine has the equivalent power to so many horses, or
horsepower.
And the rest as they say is history.........