Make a machine which gives out more work than the energy you put into it and you have perpetual motion. Inspired by the abundant supply of free energy supplied by Nature, early man did not recognise that perpetual motion was impossible. Just as Nature abhors a vacuum, so Nature reserves for herself the monopoly of the power game: only in Nature is power apparently created out of the ether. Many early writers on engineering hopefully devised means whereby mechanism would 'go of their own,' usually connected with such basic human needs as pumping water or grinding corn. Strange as it may seem, it was this very quest for the impossible that led scientists to understand why perpetual motion could not be attained. The basic tenets of engineering grew from the failures of perpetual motion...