Where in any Tailzie executed after the First Day of August One thousand eight hundred and forty-eight, the Maker of such Tailzie has declared or shall declare that an Act passed in the Tenth Year of the Reign of His Majesty King George the Third, intituled An Act to encourage the Improvement of Lands, Tenements, and Hereditaments in that Part of Great Britain called Scotland held under Settlement of strict Entail, and an Act passed in the Fifth Year of the Reign of His Majesty King George the Fourth, intituled An Act to authorize the Proprietors of entailed Estates in Scotland to grant Provisions to the Wives or Husbands and Children of such Proprietors, or either of the said Acts of Parliament, shall be applicable to such Tailzie, then and in that Case such Act or Acts, as the Case may be, shall be deemed and taken to be and shall be applicable to such Tailzie in like Manner as if such Tailzie had been executed prior to the said First Day of August One thousand eight hundred and forty-eight.