In any Class 5 county having an area between five hundred eighty (580) and six hundred fifteen (615) square miles and having a population between twenty-one thousand, six hundred eighty-one (21,681) and twenty-two thousand, six hundred eighty-one (22,681) according to the 1950 decennial census, and traversed by U.S. Highway No. 80 and in which is located a state park or junior college, and in any Class 6 county having an area between five hundred seventy-five (575) and six hundred seventy-five (675) square miles and having a population between twenty-one thousand (21,000) and twenty-two thousand (22,000) according to the 1950 decennial census, and traversed by the Natchez Trace, and in any Class 7 county having an area in excess of six hundred forty (640) square miles and a population between sixteen thousand (16,000) and seventeen thousand (17,000) according to the 1950 decennial census, and wherein there are located producing oil or gas wells, and in any Class 1 county in which there is located a state-supported college for women and a U.S. Air Force Base, the boards of supervisors are hereby authorized and empowered, in their discretion, to set aside, appropriate and expend moneys from the general fund which shall be used for the industrial and economic development programs of said counties through donations to industrial development corporations, and to maintain and support the same.