An Act to continue Two Acts of the Fifty-sixth and Fifty-eighth Years of His present Majesty, for reducing the Duties payable on Horses used for the Purposes therein mentioned, to the Fifth Day of April One thousand eight hundred and twenty one; and to reduce the Duties chargeable under certain Acts of the Forty-eighth and Fifty-second Years of His present Majesty, in respect of certain Horses, Mares, Geldings and Mules.