It will have been simplified for them not so much by modern earth-moving and dredging equipment as by the human contributions of men now long since gone on to their reward ... dreamers who ranged down the generations from Columbus to Theodore Roosevelt ... and doers as different in time and temperament as Pedrarias, whose slaves built the first Isthmian path, to Goethals, whose associates managed, after the failure of the French, to deepen that path into a waterway short-cut through which nations and men may know one another better than before.