It shall be the duty of the said commissioners on the first Monday of September, 1859, and on the same day annually thereafter to report and certify to the governor the amount received under this act, the amount of interest paid and the amount of the debts of the commonwealth redeemed and held by them, whereupon the governor shall direct the certificates representing the said indebtedness to be cancelled and on such cancellation issue his proclamation stating the fact and the extinguishment and final discharge of so much of the principal of said debt.
72 P.S. § 3642