PUBLIC LAWS-CH. 722-SEPT. 18, 1940 Unauthorized charges, etc., forbid- den. Prociso. Application of cer- tain provisions. Ante, p. 900. Filing and publica- tion of rates, etc. Notice required for change. Establishment of minimum rates. Schedules open for Inspection. Publication, etc., re- quired. Changes. Discretionary time reduction permitted. required by this section shall be published, filed, and posted; and the Commission is authorized to reject any tariff filed with it which is not in accordance with this section and with such regulations. Any tariff so rejected by the Commission shall be void and its use shall be unlawful. "(c) No common carrier by water shall charge or demand or collect or receive a greater or less or different compensation for transporta- tion subject to this part or for any service in connection therewith than the rates, fares, or charges specified for such transportation or such service in the tariffs lawfully in effect; and no such carrier shall refund or remit in any manner or by any device any portion of the rates, fares, or charges so specified, or extend to any person any privileges or facilities for transportation affecting the value thereof except such as are specified in its tariff: Provided,That the provisions of sections 1 (7) and 22 of part I (which relate to transportation free and at reduced rates), together with such other provisions of such part (including penalties) as may be necessary for the enforce- ment of such provisions, shall apply to common carriers by water. "(d) No common carrier by water, unless otherwise provided by this part, shall engage in transportation subject to this part unless the rates, fares, and charges upon which the same are transported by said carrier have been filed and published in accordance with the provisions of this part. No change shall be made in any rate, fare, charge, classification, regulation, or practice specified in any effective tariff of a common carrier by water except after thirty days' notice of the proposed change filed and posted in accordance with this section. Such notice shall plainly state the change proposed to be made and the time when such change will take effect. The Commis- sion may, in its discretion and for good cause shown, allow changes upon notice less than that herein specified, or modify the requirements of this section, either in particular instances or by general order applicable to special circumstances or conditions. "(e) It shall be the duty of every contract carrier by water to estab- lish and observe reasonable minimum rates and charges for any serv- ice rendered or to be rendered in the transportation of passengers or property or in connection therewith and to establish and observe reasonable regulations, and practices to be applied in connection with said reasonable minimum rates and charges. It shall be the duty of every contract carrier by water to file with the Commission, post, and keep open for public inspection, in accordance with such rules and regulations as the Commission shall prescribe, schedules of minimum rates or charges actually maintained and charged for interstate and foreign transportation to which it is a party, and any rule, regulation, or practice affecting such charges and the value of the service there- under. No contract carrier by water, unless otherwise provided by this part, shall engage in transportation subject to this part unless the minimum rates or charges actually maintained and charged have been published, filed, and posted in accordance with the provisions of this part. No new rate or charge shall be established and no reduction shall be made in any rate or charge, either directly or by means of any change in any rule, regulation, or practice affecting such rate or charge, or the value of service thereunder, except after thirty days' notice of the proposed new rate or charge, or of the proposed change, filed in accordance with this section. The Commission may, in its dis- cretion and for good cause shown, allow the establishment of any such new rate or charge, or any such change upon notice less than herein specified, or modify the requirement of this section with respect to posting and filing of such schedules, either in particular instances or by general order applicable to special or peculiar circumstances or [54 STAT.