It shall be lawful for the councils or council of cities of the first, second, and third classes within this Commonwealth to make an annual appropriation from the funds of such city or cities for the support and maintenance of the principal historical society located therein: Provided, That, as a prerequisite to the receiving of an appropriation, any such society shall be incorporated under the laws of the State of Pennsylvania, shall own its own building and keep it open to the public, shall have a membership of at least two hundred persons who pay annual dues of at least two dollars, shall hold, annually, at least six regular meetings that shall be open to the public, and shall at all times maintain facilities for the free storage, deposit, and inspection of official documents and records of such city or cities, and other proper public or historical archives and records.
53 P.S. § 5462