EXTRACT FROM U.S. SECRETARY OF STATE TO DON LUIS DE ONIS, SPANISH COMMISSIONER, 12 MARCH, 1818.
BRITISH AND FOREIGN STATE PAPERS (1817-1818), pp. 327-328.
“In their Note of the 20th April, 1805, to the same Minister, replying to his argument in support of the pretensions of your Government with regard to those Limits, they lay down and establish, by a chain of reasoning, which neither Mr. Cevallos, at the time, nor your Government, at any period since, have ever attempted to break, three principles, sanctioned alike by immutable justice, and the general practice of the European Nations, which have formed Settlements and held Possessions in this Hemisphere ; and by the application of which to the facts also stated in their Note, this question of the Western Boundary ought then to have been, and, eventually, must be settled.
“These principles were :
“First : 'That whenever any European Nation takes possession of any extent of Seacoast, that possession is understood as extending into the interior Country, to the sources of the rivers emptying within that coast, to all their branches, and the Country they cover, and to give it a right in exclusion of all other Nations to the same.' ”