China Covers and Cancellations Air MailDomestic 1931 (15 Apr.) C.N.A.C. envelope carried on the first flight Nanking - Peking bearing 19c. franking tied by Nanking English/Chinese c.d.s. with grey Par Avion etiquette and, on the reverse, Peiping arrival c.d.s. (16.4). Starr 37