The Powers reserve to themselves the right, at the end of five years, by mutual agreement, to inquire into the above-mentioned tariffs in case they require revision. ARTICLE XV. The affluents of the Congo shall, under all circumstances, be subject to the same regulations as the river of which they are the tributaries. The same regulations shall apply to the lakes and canals as to the rivers and streams in the territories defined in Article I, paragraphs 2 and 3. Nevertheless the Powers of the International Commission of the Congo shall not extend over the said rivers, lakes and canals, unless with the assent of the States under whose sovereignty they are placed. It is also understood that for the territories mentioned in Article I, paragraph 3, the consent of the sovereign States on whom these territories are dependent remains reserved. ARTICLE XVI. The roads, railways, or lateral canals, which shall be established for the special object of supplementing the innavigability or imperfections of the water-way in certain sections of the Congo, of its affluents and other water-courses held to be like unto them by Article XV, shall be considered in their capacity as means of communication as dependencies of the river, and shall be likewise open to the traffic of all nations. And as on the river, there shall be levied on these roads, railways and canals only tolls calculated on the expenses of construction, maintenance and administration, and on the profits due to the promoters. In the assessment of these tolls, foreigners and the inhabitants of the respective territories shall be treated on a footing of perfect equality. ARTICLE XVII. An International Commission is instituted and appointed to ensure the execution of the provisions of the present Act of Navigation. The Powers signatory to this Act, as well as those who afterwards accept it, shall at all times be represented on the said Commission, each by a delegate. No delegate shall have more than one vote, even in the event of his representing several governments. This delegate shall be paid by his own government direct. The salaries and allowances of the agents and servants of the International Commission shall be charged to the proceeds of the dues levied conformably to Article XIV, paragraphs 2 and 3. The amounts of said salaries and allowances, as well as the number, position and duties of the agents and servants, shall appear in the account rendered each year to the Governments represented on the International Commission. ARTICLE XVIII. The members of the International Commission, as well as the agents nominated by them, are invested with the privilege of inviolability in the exercise of their functions. The same guarantee shall extend to the offices, premises and archives of the Commission. ARTICLE XIX.