1 Convention for the Unification of Certain Bules Eelating to International Transportation by Air, 1929, 49 Stat. 3000; 137 League of Nations Treaty Series 11; 28 A.J.I.L. Supp. 84 (1934). Art. 30 provides, inter alia: “ (1) In. the case of transportation to be performed by various successive carriers and falling within the definition set out in the third paragraph of Article 1, each carrier who accepts passengers, baggage or goods shall be subject to the rules set out in this convention, and shall be deemed to be one of the contracting parties to the contract of transportation insofar as the contract deals with that part of the transportation which is performed under his supervision. “ (2) In the case of transportation of this nature, the passenger or his representative can take action only against the carrier who performed the transportation during which the accident or the delay occurred, save in the case where, by express agreement, the first carrier has assumed liability for the whole journey.” 49 Stat. 3000 at 3021.