The county Superintendent of Education of Bibb County shall receive an annual expense allowance to be fixed by the county board of education in such amount as the board deems appropriate. It shall be paid in equal monthly installments out of the public school funds of the county and shall be in lieu of any other expense allowances heretofore provided for the county superintendent of education. The county board shall fix the amount of the expense allowance authorized in this section by resolution duly entered upon the minutes of the board.