League of Nations — Secretariat — Contracts of Service — Administrative Tribunal — Effect of Verbal Interpretation by Subordinate Official of an Engagement Undertaken in Writing by a Public Authority — Literal and Equitable Interpretation of International Administrative Regulations — Position of Secretariat as regards Responsibility for Wrongful Decisions of Autonomous League Bodies — Civil Law Rule that a Person Promising Performance of an Act by a Third Party is Responsible for Refusal of that Third Party.