In counties having a population of not less than twenty-seven thousand, four hundred and forty-one (27,441) and not more than twenty-seven thousand, four hundred and fifty (27,450), and in counties having a population of not less than twenty thousand and forty-eight (20,048) and not more than twenty thousand and fifty-five (20,055), and in counties having a population of not less than twenty-five thousand, three hundred and ninety-four (25,394) and not more than twenty-five thousand, four hundred (25,400), and in counties having a population of not less than ten thousand, nine hundred seventy-five (10,975) and not more than ten thousand, nine hundred and eighty-five (10,985), according to the last preceding Federal Census, and 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; providing that the amount of such expenditures for office and traveling expenses shall not exceed the sum of Six Hundred Dollars ($600) 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.