The sum of fifty thousand dollars ($50,000),¹ or so much thereof as may be necessary, is hereby specifically appropriated to the Pennsylvania State Park and Harbor Commission of Erie for the purpose of building retaining walls along, and dredging the west canal basin located within, the harbor of Erie, to a depth of ten feet of water: Provided, however, That said appropriation is hereby made upon condition that the city of Erie or the citizens of said city or both shall raise and pay over to the Pennsylvania State Park and Harbor Commission the sum of twenty-five thousand dollars ($25,000), to be used by said commission for the same purposes.