If in either of the Cases aforesaid the said Arbiters shall refuse, or shall for Seven Days after Request of either Party to such Arbitration neglect to appoint an Oversman, the Lord Ordinary, on the Application of either Party to such Arbitration, shall appoint an Oversman; and the Decision of such Oversman on the Matters on which the Arbiters shall differ, or which shall be referred to them Under this or the special Act, shall be final.