These are designed to prevent Germany for a period of years from discriminating against the trade of Allied and Associated countries. They also provide for the settlement of pre-war debts, and other obligations and rules are drawn up for the fulfilment or non-fulfilment of pre-war contracts. PART XI _Aerial Navigation_ The provisions under this heading give to aircraft of the Allied and Associated countries certain specified rights in German territory and privileges similar to those enjoyed by German aircraft. PART XII _Ports, Waterways, and Railways_ Germany undertakes to grant complete freedom and equality of transport through her territories for persons and goods passing from or to the territories of any of the Allied and Associated countries, such goods in transit to be exempt from all customs and similar duties. Similarly she grants to the Allied and Associated Powers equal freedom of navigation in all her ports and waterways. Free zones in German ports are to be maintained and adequate facilities are to be provided for trade requirements without distinction of nationality. Portions of the Elbe, the Oder, the Niemen, and the Danube are declared international and placed under the supervision of the League of Nations and of International Commissions. Provision is made for a deep draught Rhine-Danube Canal should it be decided to construct it. The Rhine and the Moselle form the subject of a special series of clauses. With regard to the Rhine, France, to whom Germany is to hand over a portion of her shipping on that river, is given special rights and privileges. Provision is made for a Rhine-Meuse Canal, should Belgium desire to construct it. Exit to the north is given to the Czecho-Slovak State by the grant of a special use of the ports of Hamburg and Stettin. Certain provisions are made with regard to railway service in Germany and in transferred territory. The Kiel Canal is to remain free and open to ships of war and merchant shipping of all nations. If Germany fails to carry out the stipulations with regard to the Canal, appeal may be made against her to the jurisdiction of the League of Nations. PART XIII _Labour_ It is provided that an International Conference shall meet annually to propose Labour reforms for adoption by States composing the League of Nations. The Annual Conference will consist of four representatives from each State, two for the State and one each for employers and employed. The Conference has certain powers for the initiation of legislation to fulfil recommendations or draft conventions carried by a two-thirds majority of the delegates representing its Members. PART XIV _Guarantees_ These consist chiefly of the measures already outlined for the occupation by the Allied Powers during a period of years of the German territories west of the Rhine. If Germany fails to fulfil her obligations, such occupation may be prolonged or, if the territories or any part of them have been evacuated, renewed.