It shall be unlawful for any such person, firm, association or corporation to charge for the transportation of such crude oil through its line in excess of the following rates for each barrel of forty-two gallons transported: Six miles and less, five cents; over six miles and not more than fifteen miles, six cents; over fifteen miles and not more than forty miles, seven cents; over forty miles and not more than eighty miles, eight cents; over eighty miles and not more than one hundred miles, ten cents; over one hundred miles and not more than one hundred and fifty miles, fifteen cents; over one hundred and fifty miles and not more than two hundred miles, twenty cents; over two hundred miles and not more than two hundred and fifty miles, twenty-three cents; over two hundred and fifty miles and not more than three hundred miles, twenty-five cents.