And be: it further enacted, That it shall and may be lawful to the Heir of Entail in Possession of any such Entailed Estate as aforesaid, to grant Bonds of Provision or Obligations, binding the succeeding Heirs of Entail in Payment, out of the Rents or Proceeds of the same, to the lawful Child or lawful Children of the Person granting such Bonds or Obligations, who shall not succeed to such Entailed Estate, of such Sum or Sums of Money, bearing Interest from the Grantor's Death, as to him or her shall seem fit: Provided always, that the Amount of such Provision shall in no case exceed the Proportions following of the free yearly Rents or free yearly Value of the Whole of the said Entailed Lands and Estates, after deducting the public Burdens, Liferent Provisions, including those to Wives or Husbands authorized to be granted by this Act, the yearly Interest of Debts and Provisions, and the yearly Amount of other Burdens of what Nature soever, affecting or burdening the said Lands and Estates, or the yearly Rents or Proceeds thereof, and diminishing the clear yearly Rent or yearly Value thereof as aforesaid to the Heir of Entail in Possession ; (that is to say), for One Child, One Year's free Rent or Value; for Two Children, Two Years free Rent or Value ; and for Three or more Children, Three Years free Rent or Value in the whole : Provided always, that such Provision shall, except in the Case of the Settlement thereof by a Marriage Contract as herein-after mentioned, be valid and effectual only to such Child or Children as shall be alive at the Death of the Grantor, or to the Child or Children of which the Wife of the Grantor shall be then pregnant; and upon any such Child succeeding to the Entailed Estate, the Provision granted to him or her, in so far as not previously paid, shall be extinguished for ever, and shall never be set up as a Debt against any succeeding Heir.