53 Pa. Stat. § 2628
It shall not hereafter be lawful to erect any free bridge over the Juniata river or its tributaries, within the distance of one mile from any toll bridge constructed by any company incorporated by this commonwealth: Provided, That in case the county commissioners of any county in which such toll bridge may be situated, shall be desirous to purchase the same for the purpose of making it a free bridge, they may offer the owners of said bridge such a sum for the same as three competent disinterested persons (to be chosen, one by each of the parties and the third by the two persons thus chosen), may, after a careful view thereof, determine it to be worth; and should said company not accept the said offer (which may be made in writing to the president or secretary of said company), within fifteen days after it shall be made as aforesaid, then and in that event, it shall be lawful for said commissioners or any association of individuals, to erect a free bridge or bridges wherever they may see proper, over the said river or its tributaries.
53 P.S. § 2628