1871 DR. PERKINS IMPERFORATE COLOUR TRIALS ON PAPER CHEMICALLY PREPARED TO PREVENT ACID/DETERGENT REMOVAL OF CANCELLATION, A SUPERB UNUSED 'SET' OF THE FOUR SURFACE PRINTED VALUES 3d, 4d, 6d AND 1s. A superb and very rare unused 'set' of the four surface printed stamps used by Dr. Perkins in 1871 in connection with his trials to prevent acid/detergent removal of the cancellation and reuse of the stamps. The 'set' comprises a very fine unused imperforate 1871 3d rose pl.5 (SG103) lettered RB on very blued paper (Spec J30b), a very fine unused imperforate 1871 4d vermilion pl.12 (SG94) lettered MK with blue streaking and fine o.g. (Spec J59b), a very fine unused imperforate 1871 6d mauve pl.9 (SG109) lettered RE on very blued paper (Spec J77d) and a very fine unused imperforate 1871 1s green pl.4 (SG117) lettered SJ with blue streaking (Spec J104b). These experiments were conducted in early 1871 and authorised by the Post Office authorities. A superb group with good unused issued stamps for comparison. (8 items) (Ref 144802).
