§ 14. States which conclude an arbitration treaty have to agree upon the arbitrators. If they choose a third State as arbitrator, they have to conclude a treaty (_receptum arbitri_) with such State, by which they appoint the chosen State and by which such State accepts the appointment. The appointed State chooses on its own behalf those umpires who actually serve as arbitrators. It can happen that the conflicting States choose a head of a third State as arbitrator. But such head never himself investigates the matter; he chooses one or more individuals, who make a report and propose a verdict, which he pronounces. And, further, the conflicting States may agree to entrust the arbitration to any other individual or to a body of individuals, a so-called Arbitration Committee or Commission. Thus the arbitration of 1900 in regard to the Venezuelan Boundary Dispute between Great Britain, Venezuela, and the United States was conducted by a Commission, sitting at Paris, consisting of American and English members and the Russian Professor von Martens as President. And the Alaska Boundary Dispute between Great Britain and the United States was settled in 1903, through the award of a Commission, sitting at London, consisting of American and Canadian members, with Lord Alverstone, Lord Chief Justice of England, as President. [Sidenote: On what principles Arbitrators proceed and decide.] § 15. The treaty of arbitration must stipulate the principles according to which the arbitrators have to give their verdict. These principles may be the general rules of International Law, but they may also be the rules of any Municipal Law chosen by the conflicting States, or rules of natural equity, or rules specially stipulated in the treaty of arbitration for the special case.[15] And it can also happen that the treaty of arbitration stipulates that the arbitrators shall compromise the conflicting claims of the parties without resorting to special rules of law. The treaty of arbitration, further, as a rule, stipulates the procedure to be followed by the arbitrators who are investigating and determining the difference. If a treaty of arbitration does not lay down rules of procedure, the arbitrators themselves have to work out such rules and to communicate them to the parties. [Footnote 15: See below, § 335, concerning the "Three rules of Washington."] [Sidenote: Binding force of Arbitral Verdict.]