cover 1888 (31 July) sailor's cover to England, headed "From William Clark 2nd C Mate, H.M.S. Garnet, Zanzibar", countersigned by Commanding Officer, bearing India 2a. tied by Zanzibar squared-circle d.s. and showing, on reverse, Sea Post Office (7.8) and Aden (11.8) transit c.d.s.