An Act for explaining and amending an Act passed in the sixth year of His present Majesty's reign, intituled, An Act to recover, and preserve the navigation of the river Dee in the county Palatine of Chester; and another Act passed in the fourteenth year of His present Majesty's reign, intituled, An Act for incorporating the undertakers of the navigation of the river Dee; and for repealing the tonnage rates payable to the said undertakers; and for granting to them other tonnage or keelage rates in lieu thereof; and for other purposes therein mentioned.