State Territory — Parts of — Land boundaries — Principle of uti possidetis — Meaning and application of.

State territory — Parts of — Water boundaries — Thalweg — Operation of thalweg concept at mouth of river.

Treaties — Conclusion of — Ratification and entry into force Provisions for submission of treaty to constitutional ratification and for immediate organization of Mixed Boundary Commission prior to ratification — Whether treaty enters into force on signature — Relevance of intention of Parties.

Disputes — Arbitration — The award — Binding force of — Validity of award — Effect of non-compliance with treaty provisions on appointment of arbitrator — Effect of lapse of treaty after appointment but before arbitrator agreed to act — Whether acquiescence in award as binding operates as estoppel to later objections to its validity — Effect of arbitrator exceeding his powers — Effect of “essential error” — Effect of omissions and obscurities in award.