That where any Land or Ground belonging or hereafter to belong to His Majesty, His Heirs or Successors, within the ordering and Survey aforesaid shall be deemed by the Lord-High Treasurer or Commissioners of; the Treasury, or the Chancellor of the Duchy of Lancaster for the Time being, fit and proper for Gardens, Yards, Curtilages and other Appurtenances to be used and enjoyed with any House or Houses. or Buildings erected or to be erected upon Ground belonging , either to His Majesty, His Heirs or Successors, or to any other Proprietors, it shall be lawful for His Majesty, His Heirs or Successors, to demise or .grant such Land or Ground to any Person or Persons, or to any Bodies Politick or Corporate, under the Great Seal of Great Britain, or the Seal "of the Exchequer, or the Seal of the Duchy and County Palatine of Lancaster, for any Term or Estate not exceeding Ninety-nine Years to be computed from-the Date or making of any such Lease or Grant reflectively ; or if any such Lease or Grant be made to take effect in Reversion or Expectancy, then that the Term and Estate thereby to be granted, together with the Term or Estate, Terms or Estates in Possession of and in the same Lands and Ground shall not exceed Ninety-nine Years, computed from the Date or making thereof as aforesaid.