(3) To take appropriate measures to ensure supervision of railway stations, airports, seaports and en route, and of other public places, in order to prevent international traffic in persons for the purpose of prostitution; (4) To take appropriate measures in order that the appropriate authorities be informed of the arrival of persons who appear, prima facie, to be the principals and accomplices in or victims of such traffic. Article 20 The Parties to the present Convention shall, if they have not already done so, take the necessary measures for the supervision of employment agencies in order to prevent persons seeking employment, in particular women and children, from being exposed to the danger of prostitution. Slavery Convention 1926 Article I For the purpose of the present Convention, the following definitions are agreed upon: (1) Slavery is the status or condition of a person over whom any or all of the powers attaching to the right of ownership are exercised. (2) The slave trade includes all acts involved in the capture, acquisition or disposal of a person with intent to reduce him to slavery; all acts involved in the acquisition of a slave with a view to selling or exchanging him; all acts of disposal by sale or exchange of a slave acquired with a view to being sold or exchanged, and, in general, every act of trade or transport in slaves. Article 2 The High Contracting Parties undertake, each in respect of the territories placed under its sovereignty, jurisdiction, protection, suzerainty or tutelage, so far as they have not already taken the necessary steps: (a) To prevent and suppress the slave trade; (b) To bring about, progressively and as soon as possible, the complete abolition of slavery in all its forms. 80