Sec. 1-d. COUNTIES OF 11,996 TO 12,000. In counties having a population of not less than eleven thousand, nine hundred ninety-six (11,996), nor more than twelve thousand (12,000), 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, and any assistant he may have; provided 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.