most European rivers. In some cases they were much discussed and received various alterations and improvements. Nor were they confined to one continent.

Part II of this treatise sets forth this development in some detail; but a question of principle immediately arises, viz. May a customary rule be said to have originated in the conventional law of rivers?' It is known that the consensus of all civilized nations, repeatedly expressed or implied in a long succession of treaties, may become the source of rights independent of those very treaties. Thus, that a right of free navigation on international rivers will exist in the near future is beyond doubt. But does it exist now? The question, which can only be answered after careful consideration of the diplomatic documents and transactions, has been conveniently put by Mr. Roxburgh as follows: Are States generally in the habit of granting such freedom to all nations under a conviction that they are by law bound to do so?' 2

Now, this is a question of fact, the answer to which largely depends on the interpretation of the documents, on the personal convictions of each jurist as to what amount of universality is required, what force certain reservations carry and how long they carry it, &c., &c.3 It is therefore no wonder that no agreement of opinion. exists, and that, to take only two leading English jurists (Westlake and Hall), the one asserts, while the other denies, the right of free navigation.

1 R. F. Roxburgh, International Conventions and Third States, London, 1917, p. 87.

2 This conviction of a legal necessity or legal right as one of the essential elements of a custom (in contradistinction to a mere usage) has been particularly well brought into light by Oppenheim, International Law, i, p. 22.

3 As to Hall's notions on the Conventional law of Nations', see his International Law, pp. 7 sqq. They certainly bear part of the responsibility for his conclusions referred to in this section.

Both authors start from a survey of the practice of States, which in Westlake is particularly comprehensive and noteworthy, and in Hall stops before the Conference of Berlin (1885); and while Hall declares that free navigation has not been established either by usage or by agreements binding all or most nations to its recognition as a right ', Westlake concludes 'that a sufficient consent of States exists to warrant the assertion that a right of navigation (of which the best statement is that made for the Danube by the Treaty of Paris in 1856) exists as an imperfect right 2 on the navigable rivers traversing or bounding the territories of more than one State '.3

A definitive conclusion is not possible at this stage of the present inquiry. But, whatever may be urged against the notion of imperfect right, it seems to us that, from the present point of view, Westlake is nearer the mark than Hall; and we believe that the weight of independent authority is in favour of Westlake's interpretation.

That the principle of free navigation for all is not of universal application is mainly due to the fact that oversea Powers have not always thought it worth their while to claim it; but, whenever a real interest has induced them to intervene, the right of navigation has been granted. And we submit that, wherever this right has been enjoyed, its withdrawal, even as against non-signatory Powers, would be resented as an infringe

1 Hall, International Law, 7th ed., p. 141.

2 Not exactly in the same sense as Vattel (§ 7). Westlake means a right to the due enjoyment of which conventions are indispensable, but not therefore lacking every element of law or perfect right. The right is binding; only the details of its exercise-depending on circumstances which may vary in every case—are to be regulated by agreement. (Westlake, Collected Papers, p. 75.)

3 Westlake, International Law, i, p. 157.

4 Free navigation is besides very generally provided for in treaties of commerce, often in 'most-favoured-nation' clauses.

ment of right. No discrimination between oversea nations could be suffered; and the only differentiation in treatment which in fact exists is that between riparians and non-riparians on some rivers. This distinction originated in 1815 (cf. infra, p. 20), but, as a matter of principle, was abolished in 1856 (infra, p. 30), although some applications of the former stricter rule have subsisted much longer.

1 Cf. controversy between Great Britain and Portugal concerning the navigation of the Zambezi. (Parliamentary Papers, Africa,

No. 2 (1890). C. [5904], p. 43.)

PART II

THE PRACTICE OF STATES; DEVELOPMENT OF THE CONVENTIONAL, SYSTEM

(A) THE CONGRESS OF VIENNA

§ 10. Before the Congress of Vienna.

The question of the opening up of international rivers arose in Europe at the end of the eighteenth century. Article XIV of the Treaty of Münster (1648) had for ever closed the Scheldt to the Belgic provinces. Joseph II made an effort to put an end to this iniquity, but in vain.1 The French Revolution proved more irresistible than the will of the enlightened despot; and, by a decree of November 16, 1792, the Scheldt and the Meuse were declared open in the name of the Law of Nature. Nor did the French stop there; for in 1797–8, at the Congress of Rastatt, not content with the application of their doctrine to the Rhine, they startled the German diplomatists by stating the principle of admission of foreign flags with the consent of the contracting parties and by expressing the wish that the tributaries of the Rhine as well as the other great rivers of Germany should be open to French vessels.2 This Congress, however, bore no direct fruits. But in 1804, when France acquired the left bank of the Rhine, it became necessary to organize the navigation for the common benefit of both Powers and to provide for a system of collection of tolls less burdensome than the existing one. A Convention on the Tolls of the Navigation

1 Joseph II's controversy with the Dutch States-General is related by De Martens in his Causes célèbres, Cause viii.

2 Engelhardt, Nouvelle Revue historique, 1889, pp. 82-3.

of the Rhine' was accordingly signed in Paris on August 15, 1804.1 It considered the Franco-German part of the Rhine as common to both Empires in matters relating to navigation and commerce, and constituted a common administration for the collection of the tolls, the police of navigation, &c.

§ 11. The Treaty of Paris, May 30, 1814.

Among the menaces to the peace which they were assembled to ensure, the authors of the Treaty of Paris did not fail to include international rivers, which, giving rise to divergent interests, easily become the source of conflicts. To lay the foundations of a good understanding with regard to them became therefore one of the tasks of these peacemakers, who inserted the following Article (V) in their treaty:

'The navigation of the Rhine, from the point where it becomes navigable to the sea, and vice versa, shall be free, so that it can be interdicted to no one: and at the future Congress attention shall be paid to the establishment of the principles according to which the dues to be levied by the States bordering on the Rhine may be regulated, in the mode the most impartial and the most favourable to the commerce of all nations.

'The future Congress, with a view to facilitating the communication between nations, and continually rendering them less strangers to each other, shall likewise examine and determine in what manner the above provisions can be extended to other rivers which, in their navigable course, separate or traverse different States.'

The two sections correspond to two perfectly distinct ideas the first indicates the bases of the understanding with regard to the Rhine; the second provides for

1 For the text of the Convention, De Martens, Nouveau Recueil historique, 2nd ed., viii. 261 sqq.; Klüber, Acten des Wiener Congresses, iii. For an analysis, Kaeckenbeeck, International Rivers, §§ 35-42.

C