The modern electric motor dates back to 1831, when American physicist Joseph Henry published a paper describing an electric motor which, he showed, was basically the reverse of the electric generator. Instead of converting mechanical movement into an electric current, like the generator, his motor used electric current to produce mechanical movement. Henry's motor was the first to be constructed, although inefficiency limited its potential. In 1834 American blacksmith Thomas Davenport improved the motor's operating principles, using four magnets, two fixed and two revolving. Davenport used his motor to operate his own drills and wood-turning lathes. He went on to incorporate his motor in the electric railway, electric trolley, electric piano, and electric printing press.

However, across the Atlantic Ocean, English physicist Michael Faraday had been making advances of his own. Some of Faraday's discoveries were anticipated by Henry, but Faraday received credit by publishing the results of...