Jurisdiction — Immunity from — Foreign States — Instrumentality of — Criteria for Determining Whether a Corporation is an Instrumentality of its Government — Whether Supply of Oil to Naval Forces a Governmental Function-Immunity of Corporations which are Governmental Instrumentalities — Bases of the Doctrine of Sovereign Immunity — Immunity of Foreign Corporation under Government Control Engaging in Commercial Activities — Statement of the Foreign Government in Question — Judicial Notice of Sovereign Immunity — Whether Immunity of a Sovereign from Suit in a Foreign Court Need be Affirmatively Asserted.