XJF441242 The East African Slave Trade: Steam-Piannace of H.M.S. London chasing a slave dhow, after a sketch by Joseph Bell, engraved by W.F.Palmer, published in \'The Illustrated London News\', 1881 (engraving) by Overend, William Heysham (1851-98) (after); Private Collection; (add.info.: Under the name the \'preventative squadron\' the British Navy patrolled the East African coast in an attempt to prevent the traffic of slaves between East Africa and Asia\'; The HMS London was stationed in Zanzibar between 1878 and 1883 as part of this squadron; A dhow is a particular sort of ship that is characteristic of Zanzibar and was frequently used by slave traders;); British, out of copyright.