Lot 70519 – Dollis Hill ST5 (2)a 2d Green Phosphor in the pulp

1857-72 Dollis Hill trials; 2d red-brown imperf. vertical strip of three on handmade paper with green phosphor in the pulp, vertical tear as this paper was susceptible to tearing as it was printed on very thin paper, without watermark, affixed on cover address to the P.O. Research Station at Dollis Hill tied by Sheffield 18 DEC 1971 machine cancel (S.G. Spec. ST5 (2)a).