XEE4146935 Humphrey Potter, in charge of opening and closing the valves of Thomas Newcomen\'s machine, made it work without assistance by properly placing ropes and butees in order to open and close the valves, 1713 - Engraving in ???ciences made available to all - physics and chemistry??by Alexis Clerc - End of 19th century. Private collection. by French School, (19th century); Private Collection; (add.info.: Humphrey Potter, in charge of opening and closing the valves of Thomas Newcomen\'s machine, made it work without assistance by properly placing ropes and butees in order to open and close the valves, 1713 - Engraving in ???ciences made available to all - physics and chemistry??by Alexis Clerc - End of 19th century. Private collection.); Stefano Bianchetti; French, out of copyright.