In counties having a population of not less than thirty thousand (30,000) and not more than thirty thousand and twenty-nine (30,029), and counties having a population of not less than eighteen thousand four hundred twenty-five (18,425) and not more than eighteen thousand five hundred twenty-eight (18,528), and counties having a population of not less than forty-three thousand one hundred (43,100) and not more than forty-three thousand three hundred (43,300) and counties having a population of not less than twenty-three thousand eight hundred and eighty (23,880) and not more than twenty-three thousand nine hundred (23,900), and in counties having a population of not less than thirty-four thousand (34,000) and not more than thirty-five thousand five hundred (35,500), and in counties having a population of not less than eighteen thousand eight hundred fifty (18,850) and not more than eighteen thousand eight hundred seventy-five (18,875), and counties having a population of not less than ten thousand one hundred fifty-three (10,153) inhabitants and not more than ten thousand one hundred fifty-six (10,156) inhabitants, and counties having a population of not less than nineteen thousand one hundred (19,100) and not more than nineteen thousand one hundred fifty (19,150), and counties having a population of not less than thirty thousand four hundred (30,400) and not more than thirty thousand six hundred (30,600), according to the last preceding Federal Census, the County Boards of Trustees may make such provisions as they deem necessary for office and traveling expenses of the County Superintendent of Public Instruction; provided that the amount of such expenditures for office and traveling expenses shall not exceed the sum of Six Hundred ($600.00) Dollars per annum. The amount allowed shall be paid in the manner and in accordance with now existing laws governing the maintenance of the office of the County Superintendent.