Air Mail unused 1929-30 Air issues, a study of the different printings comprising 1929-30 Cooke 3d. monogram block of ten, Harrison 3d. (8, three used and including a marginal block of four) and Ash 3d. (31 including a corner block of nine, and a used strip of three); 1930 (Sept.) Harrison 6d. marginal block of four and pair both showing "POSTACE" at right and 1/- (10 with a corner block of four and including a pair with one showing comma flaw and one with dark carmine overprint, Ash 3d. (24, two used and including a corner block of six), 6d. (27, one used and including two blocks of four) and 1/- (9, three used). A few with faults though condition generally fine. S.G. 112-120, £1,000+