For the purpose of purchasing sites, erecting or enlarging buildings, purchasing equipment, repairing or remodelling buildings or equipment and for the purpose of defraying the maintenance cost and current running expenses of such schools and homes, the excise board of each county hereby authorized to establish and conduct such schools and homes, is hereby authorized in addition to all other levies, to make an annual levy upon all property in the county subject to taxation upon an ad valorem basis, of not to exceed one-half ( ½ ) of one (1) mill per annum, which is hereby declared not to be a current expense, and to be for a special purpose, known as County Supervised School and Home Fund, in addition to the maximum levy for current expenses now provided by law.