64 Pa. Stat. § 144
In order to prevent the confusion that would arise from issuing different warrants for the same land, and to prevent lawsuits in future respecting grants from the land office, under the aforesaid act of April 3, 1792: Be it enacted, That from and after the passing of this act, the secretary of the land office shall not grant any new warrant for land which he has reason to believe hath been already taken up under a former warrant, but in all such cases he shall cause a duplicate copy of the application to be made, on which duplicate copy he shall write his name, with the day and year in which it was presented, and he shall file the original in his office, and deliver the copy to the party applying: Provided always, That on every application so to be made and filed shall be certified, on the oath or affirmation of one disinterested witness, that the person making such application, or in whose behalf such application is made, is in actual possession of the land applied for, and such certificate shall mention also the time when such possession was taken; and the application so filed in the secretary's office shall be entitled to the same force and effect, and the same priority in granting warrants to actual settlers, as though the warrants had been granted at the time when the applications were filed; and should the decision of the court and jury, at the trial aforesaid, be in favor of the claims of the actual settlers, the secretary of the land office shall proceed to grant the warrants, upon the purchase money being paid, according to the priority of the applications filed in his office.
64 P.S. § 144