case Seymour versus fotherly in court Lord keeper one have two son and on the  marriage of his old article to settle land on the old son and his wife for  their life with remainder to the first c son in tail male successive remainder  in fee to the son father bring a bill to be relieve against the article as  gain by surprise and that it be intend to limit the remainder to the second  son on failure of issue of the first say non allocatur the father on the  marriage of his son with the plaintiff daughter in consideration of pound  portion which the father be to receive article to settle land to the use of  the son for life remainder to the wife for a jointure remainder to the first  and other son of the marriage in tail male remainder to the right heir of the  son the bill be to discover the value of the estate and what encumbrance may  be upon it and to have the article perform the defendant have another son  insist he be surprise in the article vide Griffith and buckle v buckle post  vol where marriage article much of the same nature with these be vary the  father allege surprise and the son make but tenant for life and intend that in  Vernon chancery case default of issue male of his old son his estate shall  have come to the second son charge with portion for daughter and will have  have the court interpose that the settlement may have be so make say non  allocatur and decree a specific execution of the article Reg lib b fol this  court will admit parole evidence to prove mistake in deed or agreement but not  to vary join v Statham atk baker v pain ves and will not to add to a write  agreement unless in case where there be a clear subsequent and independent  agreement vary the former rich v Jackson Br Ch Rep et vide the marquis of  Townshend v Stangroom Ves where the doctrine on this subject be very much  consider and the lead case be full state Robson v Collins Ves Woollan v hear  ibidem nor by the rule of law independent of the statute of fraud will parole  evidence be admit to contradict a write agreement ibidem as to the practice of  the court in regard to marriage article in particular vide Beachinall v  Beachinall ante p and case cite in not there