The Duties to be performed by the Grand Jury may in Cases where no other Provision is made by this Act be performed by any Eight of the Body, and such Duties shall be to attend at the Great Barmote Courts, and at any other Time upon the Summons of the Barmaster or of any Deputy Barmaster, such Summons to be delivered to all the Members of the Grand Jury, or to be left at their respective last or usual Places of Abode, at least Three Days before the Day on which their Attendance is required to go down into any Mine, Vein, or Mineral Works, and view the same, and give their Opinion on such Matters as are required, of them in any Bill of Directions or Cross Bill delivered to them, and generally to do and perform all such Acts and Duties as are in this Act mentioned as being Acts to be done or Duties to be performed by the Grand Jury.