[5.] That, by the side of his international law, with its basis in natural law, there was also a positive international law, was not unrecognized by Grotius, but his purpose was merely to depict a system of international law which should compel universal observance irrespective of time and nation. And shortly after Grotius, Zouche and his followers did indeed attempt, in opposition to him, to formulate just such a positive international law, but it could not win for itself, at any rate in the seventeenth century, any great recognition; development was overshadowed by the system of Grotius, and many of his rules of natural law gradually obtained recognition in practice as customary law. But the increasing intercourse of states in the eighteenth century called forth a more positive school of international jurists, and the works of Bynkershoek, Moser, and Martens fertilized the soil on which in the nineteenth century there could gradually grow a really positive theory of international law, even if the scales which betoken its past connexion with natural law still adhere to the international law of to-day.
International legislation initiated by the Congress of Vienna.
[6.] A positive theory of international law was demanded by the fact that in the first quarter of the nineteenth century, with the Final Act of the Congress of Vienna, the quasi-legislative activity of international conventions asserted itself for the first time. From then onwards, general international law was frequently evolved by means of an international convention. It was in this way that the permanent neutralization of Switzerland, Belgium, and Luxemburg was effected, the navigation of the so-called international rivers in Europe declared free, the slave-trade abolished, the grades of diplomatic agents regulated, privateering abolished, the necessity of effectiveness in a blockade recognized, the principle 'free ships, free goods' finally established, neutral goods on enemy ships declared free, rules provided in the interest of those wounded in battle, explosive bullets under the weight of 400 grammes forbidden, the Suez Canal neutralized, and so forth.
International Administrative Union.
[7.] Another fact of great importance is the endeavour, which first manifested itself in the World Postal Union of 1874, to carry out the international administration of common interests, economic and other, by means of more or less general international unions. In this way a series of international administrative unions, often conjoined with special international boards, have been called into existence.
Legislation of the Peace Conferences and of the Naval Conference of London.
[8.] With the end of the nineteenth and the first decade of the twentieth century, in which occur the first and second Peace Conferences at The Hague and the Naval Conference of London, the development of international law enters upon a new and pregnant epoch. If hitherto, despite the momentous law-making treaties of the nineteenth century, international law was essentially a book-law, a system erected by greater or smaller authorities on the foundations of state practice and in its details often uncertain and contested, it is now subjected more and more, and in a wide domain, to the legislating influence of law-making international conventions. To mention only the principal matters: A code has been issued which, full of lacunae as it is, nevertheless encompasses the whole area of land war; it has been laid down that war shall only be begun by a declaration of war; the employment of force for the recovery of contract-debts has been forbidden; the rights and duties of neutrals in land war and naval war, the treatment of enemy merchant vessels at the outbreak of hostilities, and the conditions of the conversion of merchant vessels into men-of-war have been legislatively fixed; rules concerning the laying of submarine mines, concerning bombardment by naval forces in time of war, concerning the application of the principles of the Geneva Convention to naval warfare, concerning certain limitations on the right of prize in naval warfare have been agreed on; many states have concurred in a prohibition of the discharge of explosive missiles from air-ships; and a code of the rules of naval warfare, so far as it touches the trade of neutrals, dealing with the topics of blockade, contraband of war, unneutral service, destruction of neutral prizes, sale of enemy merchantmen to neutrals, enemy property, convoy and so forth, has been agreed on, though still unratified.
The Permanent Court of Arbitration and other international courts.
[9.] It is noteworthy that the first Hague Conference established a permanent international arbitral tribunal and that the second Hague Conference decided on the establishment of an International Prize Court and produced a plan for a standing international court at The Hague. Hitherto there have been no international courts for the decision of disputes, and if contending powers have been ready to refer their disputes to arbitration, they have always first had to form an arbitral tribunal; but now there is in existence an actual International Court of Arbitration, and other international courts are in contemplation.
The Hague Peace Conferences as a permanent institution.