Whenever I travel to the Caribbean, I’m reminded of the discussion the Greek-Irish travel writer Lafcadio Hearn had aboard a steamboat, travelling from New York to the French West Indian island of Martinique in the summer of 1887. What, asks Hearn, constitutes the colour “tropical blue”? As the ship nears the Antilles, Hearn repeatedly declares he’s seen it only to be rebuffed by a fellow passenger, “a nice old French gentleman from Guadeloupe”. “He tells me I do not yet know what blue
