The Rights, Powers, Privileges, and Authorities hereby made exerciseable by the Duke of Cornwall, or which shall otherwise be exerciseable by the Duke of Cornwall, shall be exerciseable during such Time as any future Duke of Cornwall shall be under the Age of Twenty-one Years, in the Name and on behalf of such Duke of Cornwall, by the Sovereign of the United Kingdom for the Time being as Guardian of such Duke, or by any Persons acting under the Authority of the Sovereign of the United Kingdom for the Time being; and all Acts, Matters, and Things to be done in the Name and on behalf of the Duke of Cornwall for the Time being who shall be under the Age of Twenty-one Years by the Sovereign of the United Kingdom as such Guardian, or by any Person or Persons acting under the Authority of the Sovereign in pursuance of and in conformity with the Powers or Authorities to them in that Behalf committed by the Sovereign, shall be good, valid, and effectual in Law as if the same had been and were done, and the same shall to all Intents and Purposes be taken to have been done, by such Duke of Cornwall himself in his own proper Person, and at his full Age of Twenty-one Years; and the Appointment of the Persons to act as aforesaid in the Name and on behalf of any such Duke of Cornwall may be from Time to Time made by the Sovereign, by Warrant under the Royal Sign Manual, to be countersigned by any Three or more of the Commissioners of the Treasury of the United Kingdom : Provided always, that all Offices, Appointments, and Employments relating to the Duchy of Cornwall, or the Possessions thereof, given or bestowed during such Time as any Duke of Cornwall shall be under the Age of Twenty-one Years, which ma)' by Law be given or bestowed during Pleasure, shall be determinable by such Duke of Cornwall at any Time after he shall attain the Age of Twenty-one Years.