case green v smith on exception December the that if a man covenant to lie out  a sum in the purchase of land and devise his real estate before he have make  such purchase the money to be lie out will pass to the devisee a article for  the purchase of land and die it happen afterward that the seller can not make  a good title to the land and the question be between the heir at law and the  executor of a whether the purchase money be to be consider as land or personal  estate Lord chancellor in this cause lie down the follow rule that agreement  to be perform be often consider as perform for if a man covenant to lie out a  sum of money in the purchase of land general and devise his real estate before  atkins he have make such purchase the money agree to be lie out will pass to  the devisee milner v mill mos Greenhill v Greenhill pre Charles Lingen v  Sowray p W p W S c cite potter v potter Ves beauclerk v mead post vol Oldham v  Hugh post vol Pullyn v ready post vol Whittaker v Whittaker bro Charles Rep  see also Guidot v Guidot post vol that where a man have make his will  afterward enter into a contract for the purchase of land the land contract for  will not pass by the will but descend to the heir at law Langford v Pitt p W  Alleyn v Alleyn mos say vide cotton v cotton Charles Rep that where a ancestor  after the make of a will agree for the purchase of particular land the heir at  law will have a right to they provide a good title can be make otherwise if it  can but it be go too far to say that though the heir at law can have the land  yet he shall have the money so intend to be lie out therefore his lordship see  no ground for give direction to perform the agreement or to pay over the  purchase money Reg lib a fol that if a man give a portion to his daughter by a  will and afterward advance her with the like sum it shall go in ademption of  the legacy see Bellasis v Uthwatt ante note that the vendor of the estate be  from the time of his contract consider as a trustee for the purchaser and the  vendee as to the money a trustee for the vendor vide pollexfen v more post vol  that in billsf or specific performance this court never give relief where the  act be impossible to be do but leaves the party to his remedy at law that  where a ancestor have agree for the purchase of particular land but die before  it be quite complete if the heir at law bring his bill against the devisees  who claim the real estate of the ancestor by a will make before the purchase  of those particular land the vendor of these land where he have a doubIful  title must be make a defendant to the suit otherwise if his title be clear