Section 1. From and after the passage of this Act, in all counties of the State of Texas which had a population of not less than thirty-four thousand, six hundred (34,600) and not more than thirty-four thousand, seven hundred (34,700), according to the last preceding Federal Census, the salary of the County Superintendent of Public Instruction shall be set by the County Board of Trustees at an amount not to exceed Thirty-six Hundred Dollars ($3600) per annum and not less than Twenty-eight Hundred Dollars ($2800) per annum to be paid in accordance with and in the manner as provided by a General Law governing the maintenance of the office of County Superintendent of Public Instruction.