The county governing body of the county comprising the Thirty-seventh Judicial Circuit is hereby authorized, empowered, and directed to pay, in the discretion of the county governing body, a county salary supplement of ten thousand dollars ($10,000) per annum to each circuit judge of the Thirty-seventh Judicial Circuit. The supplement hereby authorized shall be paid in equal monthly installments out of the general fund in the county treasury, shall be in addition to the salary paid such judges by the State of Alabama, and shall be in addition to any other county expense allowance or supplement heretofore provided by law which is payable from the county.