The double cylinder was Murray 's invention , he paid Richard Trevithick a royalty for the use of his patented high pressure steam system .
The double cylinder was Murray 's invention , he improved upon it , using two cylinders rather than one to give a smoother drive .
The double cylinder was Murray 's invention , he paid Richard Trevithick a royalty for the use of his patented high pressure steam system , but improved upon it , using two cylinders rather than one to give a smoother drive .