Citing Vattel, Grotius, Montesquieu and other established authorities in international law, this pamphlet argues that as the slave trade has been found "contrary to the law of nature and nations" (24), European powers should have the collective right to intervene to stop the continued enslavement of Africans. A particular case is made against Spain's slave trade on the north west coast of Africa, which, the author argues, is jeopardising the success of Sierra Leone and other European colonial experiments in West Africa.