Tonnage. Mutual recognition of ship measurement certificates, arrangement between United States and Poland. effecting adherence of Free City of Danzig to agreement between United States and Poland, effected by exchanges of notes signed Jan. 17, Mar. 14, and Apr. 22, 1030. and Oct. 5, 1934 (Executive agreement series 71), effected by exchange of notes; singned Dec. 4, 1937, effective Dec. 19, 1937.