national kuy which declires, that. if there be more than one channel ina hody of water dividing conterminous stites, the deepest channel is the mid-chaunel or thalweg for the purposes of territorial demarcation. According to Grotius: “A river that separates two empires is not to he considered barely as water, but as water contined within such and such banks and running in such and such channel." According to Vattel: “Tf, of two nations inhabiting the opposite banks of the river, either party can prove that they themselves. or those whose viehts they inherit, were the tirst setders in those tracts, it is to be supposed that both nations came there at the same tine, since neither of them can give any reason for claiming the preference; and in this ease the dominion of each will extend to the middle of the river.”? sir Travers Twiss has well said that **Grotius and Vattel speak of the avddle of the efrov as the line of demareation between two juris- dictions, but modern pubticists andl stutesmen prefer the more accurate and more equitable houndary of the wiedehaniel. Tf there be more than ove channel of a river, the deepest channel is the midebanunel for the purposes of territorial demarcation; and the boundary line will be the line driwn along the surface of the stveam corresponding to the line of deepest depression of its hed. Thus we find in the Treaty of Angovie (17 Sept. 1808) concluded between the Grand Duehy of Baden and the Helvetie Canton of Angovie. that the thaleeyg, ov water frontier line. is detined to he ‘the line drawn along the greatest depth of the stream. and as far as bridges are concerned, *the line across the middle of each bridge.” The islands on either side of the midchannel are regarded as appeni- uges to either bank: and if they haye onee been taken possession of by the nation to whose Dank they are appendant, a change in the midchannel of the river will not operate to deprive that nation of its possession. although the water frontier line will follow the changes of the widehannel.”* See also Bluntschli, Sec. 208. Lardy’s trans. ; Rivier, vol. lL. pp. 142, 16s, Hall says that where the boundary ~ fol- tows a river. and it is not proved that either of the riparian states possess « good tithe to the whole bed, their territories are separated by a line running down the middle, exvept where the stream is navigable, in which case the centre of the deepest channel, or, as it is asaally
« De Juve Belli ae Pacis, 11, e. 3, See. 17. 6 Deait des fons, Bk. 1. c., NXIT, See, 20.
The Law of Nations, 1 pp. 207-8.
