The board of commissioners may pay, out of the county funds not otherwise appropriated, a sum of money to a county historical society , qualified under section 1930, to assist in paying the running expenses. Where a society is comprised of residents of more than one county, the commissioners of the respective counties may jointly pay the sum in such proportion as they shall agree.
No appropriation shall be renewed until vouchers have been filed with the commissioners showing that the appropriation for any prior year has been expended for the purpose herein designated.
16 P.S. § 1929