Provided always, and be it further enacted, That it shall be lawful for the said Sir George Henry Rose, during his Life, and for such Person or Persons as he shall by any Writing: under his Hand nominate for that Purpose, in case of his Death, to appoint for one Turn only, and subject to the Approbation of the said House of Lords, on such Appointment being notified to the House, any Person duly qualified to any one of the said Offices at the Table or the House of Lords, which may become vacant by Death or Superannuation or Promotion, during the Life of the said Sir George Henry Rose, or within Twenty-one Years from the Time of his Death, except as to such Appointment as is hereby vested in His Majesty, His Heirs and Successors ; but after the Lord Chancellor or Speaker for the Time being of the said House of Lords shall have made on the Occasion of such Vacancy any Promotion in such Offices which he may deem expedient tor the Service of the House, or to such vacant Office, if no such Promotion shall be made.