The sum of seventy-five thousand dollars ($75,000) is hereby appropriated to the Pennsylvania State Park and Harbor Commission of Erie¹ for the carrying out of the provisions of this act. Said appropriation is made, however, upon the condition that the city of Erie, the county of Erie, and citizens of Pennsylvania, or others interested, shall first have provided in the aggregate a like sum of seventy-five thousand dollars ($75,000), to be expended on the construction of a road or roads leading to and through this property. Proof that such sum has been paid or secured to be paid to the commission to be furnished to the Auditor General of Pennsylvania.