From and after the passing of this Act it shall be lawful for the respective Persons for the Time being entitled to the First Estate of Freehold in the Mineral Duties respectively payable within the several Manors or Liberties ofAshford, Hartington, Peak Forest, Tideswell, Stoney MiddletonandEyam, Youlgreave,andLitton,by Writing under their respective Hands, to appoint fit and proper Persons, qualified as is therein-before provided with respect to the Steward to be appointed by the Queen, to act as Stewards for the aforesaid Manors or Liberties respectively, and each such Steward shall hold his Office during the Will and Pleasure of the Person or Persons by whom he shall have been appointed; where several Manors are united into One Liberty for the Purposes of this Act, as herein-after provided, One Steward only is to be appointed for each united Liberty.