however, intimate that residence within the territory transferred and allegiance to the new sovereign thereof are essential to the retention of title.1

The territory of a State consists of the area, both land and water, confined by definite boundaries, and over which an exclusive right of sovereignty is claimed and enjoyed. The extent of the area is in a broad sense limited by the requirements of the law of nations. The extent of the control which the State is perImitted to exercise therein is likewise so held in restraint or determined.3

The extent of both the right and the duty of a State to do justice within its own domain, as well as elsewhere, is also fixed by

Dec. 10, 1898, Malloy's Treaties, II, 1693. Cf. United States v. Repentigny, 5 Wall. 211.

1 According to Art. VI of the convention between the United States and Denmark of Aug. 4, 1916, providing for the cession of the Danish West Indies: "Danish citizens residing in said islands may remain therein or may remove therefrom at will, retaining in either event all their rights of property, including the right to sell or dispose of such property or its proceeds; in case they remain in the islands, they shall continue until otherwise provided, to enjoy all the private, municipal and religious rights and liberties secured to them by the laws now in force. If the present laws are altered, the said inhabitants shall not thereby be placed in a less favorable position in respect to the abovementioned rights and liberties than they now enjoy.

"Danish citizens not residing in the islands but owning property therein at the time of the cession, shall retain their rights of property, including the right to sell or dispose of such property, being placed in this regard on the same basis as the Danish citizens residing in the island and remaining therein or removing therefrom, to whom the first paragraph of this article relates." Treaty Series No. 629, Am. J., XI, Supp., 57-58.

In the treaty of peace with Germany of June 28, 1919, there was frequent provision that persons habitually resident in territory transferred, who elected to opt for the nationality of the transferor, and in consequence were obliged to transfer their residence to its domain, should still be entitled to retain their immovable property in the ceded territory. See, for example, Arts. 37 and 106.

Hall, 5 ed., 100, quoted in Moore, Dig., I, 615. See, also, Bonfils-Fauchille, 7 ed., §§ 483-489; Calvo, 5 ed., I, 382-384; Oppenheim, 2 ed., I, §§ 168-171; Rivier, I, 135-143; Pradier-Fodéré, II, 144-151; Martens, I, 451-459; Woolsey, 6 ed., 67-68; Beale's Cases on Conflict of Laws, III, Summary, § 19. 3Cf. Reg. v. Keyn, 13 Cox C. C. 403, 2 Ex. D. 63; Beale's Cases on Conflict of Laws, I, 1.

international law. Inasmuch, however, as the scope of what may be described as the privileges and obligations of jurisdiction is not always to be ascertained or measured by reference to the territorial limits of a State, or by the degree of control which it may lawfully exercise within those bounds, the subject is discussed elsewhere.1

(2)

Various Territorial Limits

$135. Artificial Lines.

(a)

A treaty may provide that the boundary between two States shall follow certain imaginary lines, such as a parallel of latitude or a meridian of longitude, or a straight line connecting two given points.2

$136. Mountains and Hills.

(b)

A range of mountains or hills may be the boundary between two States. In such case the line of demarcation follows the watershed. Professor Moore has observed that "this rule, while

1 Rights of Jurisdiction, infra, §§ 218-265; Duties of Jurisdiction, infra, §§ 266-269.

2 See, for example, Art. I of the treaty between the United States and Mexico, Dec. 30, 1853. This Article also provided for the survey and establishment of the boundary line by a mixed commission, and declared that "the dividing line thus established shall in all time be faithfully respected by the two Governments." Malloy's Treaties, I, 1121. Mr. Cushing, Attorney-General, was of opinion that in view of the language of the treaty, the monuments and other descriptions of the line as established by the Commission should be regarded as the true line of demarcation, even though it should afterwards appear that "by reason of error of astronomical observations or of calculation, it varied from the parallel of latitude where that was the line, or in the other part did not make exactly a straight line." 8 Ops. Attys.-Gen., 175-176, Moore, Dig., I, 615.

Concerning the error in the original demarcation of the Northeastern Boundary of the United States at Rouse's Point, see Moore, Dig., I, 615, note, citing Moore, Arbitrations, I, 70-71, 80, 112, 119, 129, 135-136, 149-153. See United States v. Texas, 162 U. S. 1; also Moore, Dig., I, 616, concerning the interpretation of Art. IV, of the treaty between the United States and Spain of Feb. 22, 1819. See treaty between the United States and Great Britain, April 11, 1908, providing for the more complete definition and demarcation of the international boundary between the United States and the Dominion of Canada, Malloy's Treaties, I, 815, Am. J., II, Supp., 306. Also Lord Curzon of Kedleston, "Frontiers", Roumanes Lecture, Oxford, 1907. 3 Mr. George Canning, British Foreign Secretary, wrote to Mr. S. Canning, Dec. 8, 1824, with reference to the establishment of a line of demarcation between British and Russian Possessions in Alaska: "It is quite obvious that the boundary of mountains, where they exist, is the most natural and effectual boundary." Proceedings, Alaskan Boundary Tribunal, Appendix

simple enough in principle, is often exceedingly difficult of application.” 1

(c)

Rivers

(i)

§ 137. Preliminary.

In the Middle Ages, rivers which separated alien peoples or tribes were looked upon as neutral barriers rather than areas susceptible of nice division and capable of ownership.2 There gradually arose, however, a sense of the necessity for the assertion of control over such waters; but there was confusion of thought as to the nature and extent of that control. Rivers served as natural arteries of commerce as well as natural boundaries. The matter of navigation was of as great moment as that of territorial limits. For that reason, early writers announced the principle of co-dominion, which assigned to the opposite riverain proprietors rights of sovereignty over the entire stream. Men found it difficult to reconcile the claim of exclusive sovereignty asserted by one State over any portion of the stream, with the claim of another to exercise privileges of navigation therein. No doubt the latter claim had a marked effect upon the scope of the former. Nevertheless, the requirements of navigation were not decisive of the problem whether a line of division might be drawn through the waters of a river in recognition of sovereign rights of the States on either side of such a boundary. It came to be understood

to Case of the United States, Vol. II, 210. See line of demarcation between the Russian and British Possessions in North America, contained in the AngloRussian Convention of February 28 (16), 1825, and embodied in Art. I of the Convention between the United States and Russia of March 30, 1867, providing for the cession of Alaska, Malloy's Treaties, II, 1521.

1 Moore, Dig., I, 616, note. As evidence of the truth of his statement Professor Moore refers to the question as to the "Highlands" in the Northeastern Boundary dispute between the United States and Great Britain, citing Moore, Arbitrations, I, 65–68, 78, 100, 109, 114, 131, 158–161.

Concerning the controversy between Chile and the Argentine Republic, whether the boundary between their respective territories should, according to existing conventions, be determined by the watershed or by the highest peak of the Andes, and the agreement to adjust the difference by arbitration, see For. Rel. 1896, 32-34; also Moore, Arbitrations, V, 4854-4855.

See, also, award of the arbitrator January 30, 1897, in the Manica Arbitration between Great Britain and Portugal, where the boundary followed a plateau, the watershed of which was not, for reasons given, regarded as the true line of demarcation, Moore, Arbitrations, V, 4985-5015.

2 See historical review by E. Nys, in his Droit International, 2 ed., I, 423–437, citing, at 424, H. Helmolt in Historisches Jahrbuch, 1896, pp. 235 et seq. ' Id., I, 425.

that such a line could be drawn. In accordance with the views of Grotius and Vattel, nations were agreed that it should pass through the middle of the stream. This method of division proved, however, to be unsatisfactory in the case of navigable rivers; for, in disregarding the course of the principal channel, it was likewise heedless of the equities of the State which happened to be the more remote therefrom. Nor did it adapt itself to gradual changes which such channel might undergo.2 As a result, at the beginning of the nineteenth century, riparian States began to conclude treaties, which proposed a different method of division, and which has since become the accepted mode of indicating the frontier. There has thus developed a practice manifesting general adherence to a particular doctrine.3

138. Thalweg.

(ii)

It has long been agreed that when a navigable river forms the boundary between two States, the dividing line follows the thalweg of the stream. The thalweg, as the derivation of the word in

1 De Jure Belli et Pacis, Book II, Chap. 3, Secs. 7 and 8; Chitty's Vattel (1859), Chap. 22, Sec. 266, p. 120.

2 E. Engelhardt, Du Régime Conventionnel des Fleuves Internationaux, Paris, 1879, 73; Pierre Orban, Etude de Droit Fluvial International, Paris, 1896, 342

346.

3 Art. VI of Treaty of Luneville, Feb. 9, 1801, De Clercq, Traités, I, 426, following the views expressed by the French plenipotentiaries at the Congress of Rastadt in March and April, 1798.

4 Numerous treaties since the beginning of the nineteenth century make express provision that the frontier along navigable rivers shall follow the thalweg. See, for example, Art. V of the definitive treaty between France and the Allies of May 30, 1814, Brit. and For. State Pap., I, Pt. I, 156; also collection of treaties containing similar provisions, in the argument of the United States in the Chamizal Arbitration (Washington, 1911), 10-21. Among recent conventions to the same effect may be noted that between the Argentine Republic and Brazil of Oct. 6, 1898, Brit. and For. State Pap., XC, 85; also that between Great Britain and France of June 14, 1898, for the delimitation of possessions west of the Niger, Brit. and For. State Pap., XCI, 38, 45. Cf. also Art. I, Treaty of Constantinople, between Turkey and Bulgaria, of Sept. 16/29, 1913, Brit. and For. State Pap., CVII, 706, 709.

The treaties of the United States concerning river boundaries lack uniformity of expression. Art. II of the definitive treaty of peace with Great Britain of Sept. 3, 1783, provided that the frontier should follow the "middle" of boundary rivers as well as of water communications between the Lakes. Malloy's Treaties, I, 587. Art. I of the Webster-Ashburton Treaty of Aug. 9, 1842, provided that the frontier along the river St. John should follow the "middle of the main channel." Id., I, 651. The treaty of April 11, 1908, concerning the Canadian international boundary, provided in Art. II respecting the St. Croix River, that the line should "follow the center of the main channel or thalweg as naturally existing, except where such course would change or disturb or conflict with the national character of islands as already established by mutual recognition and acquiescence." Id., I, 818. This is

dicates, is the downway, or the course followed by vessels of largest tonnage in descending the river.1 That course frequently, if not commonly, corresponds with the deepest channel. It may, however, for special reasons take a different path. Wheresoever that may be, such a course necessarily indicates the principal artery of commerce, and for that reason is decisive of the thalweg.2

the first boundary convention of the United States in which the term thalweg was employed.

Art. II of the treaty with Spain of Oct. 27, 1795, provided that the boundary along St. Mary's River should follow the "middle thereof"; while Art. IV declared that the "western boundary of the United States which separates them from the Spanish colony of Louisiana is the middle of the channel or bed of the river Mississippi." Id., II, 1641, 1642. Art. III of the treaty with Spain of Feb. 22, 1819, provided that the boundary should follow the "course" of the Red River between specified points, all islands therein being assigned to the United States. Id., II, 1652–1653.

Art. II of the treaty with Mexico of Jan. 12, 1828, declared that between specified points the boundary should follow the "course" of the Rio Roxo or Red River. Id., I, 1083. According to Art. V of the Treaty of GuadalupeHidalgo of Feb. 2, 1848, the boundary was to proceed up the "middle" of the Rio Grande, "following the deepest channel where it has more than one"; also down the "middle" of a specified branch of the river Gila. Id., I, 1109. Art. I of the Gadsden Treaty with Mexico of Dec. 30, 1853, referred to the "middle" of the Rio Grande, and likewise to that of the Colorado. Id., I, 1122. In the preamble of the boundary convention with Mexico of Nov. 12, 1884, it was declared that according to the provisions of the two last-mentioned treaties the dividing line follows the "middle of the channel of the Rio Grande and Rio Colorado"; and it was, therefore, provided in Art. I that the dividing line should forever "follow the center of the normal channel of the rivers named, notwithstanding any alterations in the banks or in the course of those rivers, provided that such alterations be effected by natural causes through the slow and gradual erosion and deposit of alluvium, and not by the abandonment of an existing river bed and the opening of a new one." Id., I, 1159-1160. 1 Declares Westlake: "When a river forms the boundary between two States it is usual to say that the true line of demarcation is the thalweg, a German word meaning literally the 'downway'; that is, the course taken by boats going downstream, which again is that of the strongest current, the slack current being left for the convenience of ascending boats. Thal in the sense of valley enters into thalweg only indirectly. The immediate origin of the word lies in the use of berg and thal to express the upward and downward directions on a stream, like amont and aval in French.' Int. Law, 2 ed., I, 144, and note 1.

Declared the Supreme Court of the United States in the case of Louisiana v. Mississippi, 202 U. S. 1, 49: "The term 'thalweg' is commonly used by writers on international law in definition of water boundaries between States, meaning the middle or deepest or most navigable channel. And while often styled fairway' or 'midway' or 'main channel', the word itself has been taken over into various languages. Thus, in the treaty of Luneville, Feb. 9, 1801, we find 'le Thalweg de l'Adige', 'le Thalweg du Rhin', and it is similarly used in English treaties and decisions, and in the books of publicists in every tongue."

According to Art. III of the Draft of International Regulations for the Navigation of Rivers, adopted by the Institute of International Law in 1887, "The boundary of the States separated by the river is marked by the thalweg; that is, the median line of the channel.” “Annuaire, IX, 182, J. B. Scott, Resolutions, 78.

2 Minnesota v. Wisconsin, 252 U. S. 273, 282; Baker's 4th ed. of Halleck, 182, § 23.