And it is hereby enacted That upon produceing such Certificate or Debenture for any Quantity of Hides Backs or Butts of Leather to the Collector who received His Majesties Duties for such Leather and upon making sufficient Proof upon Oath before such Collector who hath hereby power to administer the same That the Quantity of Hides Backs or Butts so exported or shipped for Exportation beyond the Seas and which shall be expressed in such Certificate of the said Customer or Collector of the Port are the very same Backs Butts or Hides of Leather for which hee the said Collector for the Duties upon Leather hereby granted did actually receive His Majesties Duties in every such Case the said Collector for the said Duties upon Leather shall forthwith out of the Moneys in his Hands for His Majesties Use of the said Duties upon Leather and in default thereof then the Co[m]missioners for the said Duty upon Leather shall repay or cause to be repaid to the Person or Persons who shall produce such Certificate or Debenture from the said Customer or Collector of the Port aforesaid Two thirds of the Duties which were before received for the said Leather so exported or shipped to be exported as aforesaid.