opportunities elsewhere. The population was to fall gradually from 6,150 in 1817 to less than 4,000 by 1890. Charles Darwin spent six days of observation on the island in 1836 during his return journey on HMS Beagle. Controversial figure, Dr. James Barry, also arrived that year as principal medical officer (1836–1837). In addition to reorganising the hospital, Barry highlighted the heavy incidence of venereal diseases in the civilian population, blaming the government for the removal of the St Helena Regiment, which resulted in destitute females resorting to prostitution. Following the conquest of Aden in January 1839 and the establishment of a coal station there, the journey time to the Far East (via the Mediterranean, the Alexandria to Cairo overland crossing and the Red Sea) was roughly halved compared with the traditional South Atlantic route. This precursor to the effects of the Suez Canal (1869), coupled with the advent of steam shipping that was not dependent on trade winds led to a gradual reduction in the number of ships calling at St Helena and to a decline in its strategic importance to Britain and economic fortunes. (A 2020 report adds that the island's prosperity ended after 1860 when "the Suez Canal shifted trade routes north"/) The number of ships calling at the island fell from 1,100 in 1855; to 853 in 1869; to 603 in 1879 and to only 288 in 1889. In 1839, London coffee merchants Wm Burnie & Co described St Helena coffee as being of "very superior quality and flavour". In 1840 the British Government deployed a naval station to suppress the African slave trade. The squadron was based at St Helena and a Vice Admiralty Court was based at Jamestown to try the crews of the slave ships. Most of these were broken up and used for salvage. Between 1840 and 1849, 15,076 freed slaves, known as "Liberated Africans" were landed at Rupert's Bay on the island, of which number over 5,000 were dead or died there. The final number up to the 1870s when the depot was finally closed has not yet been accurately determined, but would be over 20,000. Surviving freed slaves lived at Lemon Valley – originally the quarantine area, later for women and children, Rupert's and High Knoll, and only when numbers became too great were they sent to Cape Town and the British West Indies as labourers. About 500 remained on St