Engine power or Ox power

[andyswann]

Why do we typically measure engine torque in horse power, rather than Oxen power, considering the role played by the Ox over the centuries?

[Clanad]

We probably don't know definitevely... except the term appears to have orginated with James Watt, inventor of the steam engine. So the story goes, he was watching horses draw coal from a mine and determined a definition of how much work, mathmatically, a horse coud do so as to measure the work his steam engine could do by comparison. If the work had been accomplished by oxen we most likely would speak in terms of OP...