In each county of this State with a population of not less than thirty thousand, nine hundred and twenty (30,920) and not more than thirty thousand, nine hundred and twenty-five (30,925), and in counties having a population of not less than fourteen thousand, four hundred and sixty (14,460) and not more than fourteen thousand, four hundred and sixty-five (14,465), and in counties having a population of not less than seven thousand, one hundred (7,100) and not more than seven thousand, one hundred and twenty-five (7,125), as shown by the Federal Census last preceding such action, the County School Board of Trustees is hereby authorized to set aside from the Available School Funds of the county, in accordance wtih the provisions of the General Law governing the assessment for the support of the County Superintendent’s Office, an amount not to exceed Six Hundred Dollars ($600) to defray the expenses of the County Superintendent and County School Board of Trustees of such counties in the administration of the scholastic affairs of the county.