At the mid-century, Cornelius Arnold penned a frothy paean to British commerce and the ‘unrivall’d Empire of the Main’ on which so much of its wealth was based. Written at the time the Royal Africa Company lost its monopoly to a new consortium of merchants, it inevitably featured the slave trade, noting the ‘sooty Sons’ sent to the West Indies to ‘drag the galling Chain of Life’. Arnold felt sure the ‘jovial crews’ who shipped the Africans could effortlessly endure the torrid zone in which the trade was conducted. He was an incurable optimist as well as a racist. As other writers were well aware, the torrid zone conjured up images of searing heat and sultry climes, of environmental constraints and innumerable insects that tortured body and soul.

It is worthwhile parsing these constraints according to a Braudelian formula. Some clearly belong to the longue durée of Caribbean history, featuring hurricanes, rainy seasons, and the volcanic landscapes of the Windward Islands which, as Colin Chisholm recognized, produced not only earth tremors but micro-climates quite unlike the flat islands of Barbados and Antigua. The winds of the Caribbean also generated pathways across wide waters, lairs for privateers and pirates, such as the Bermuda or Florida straits through which so much of the traffic northwards passed. And the often unpredictable weather affected the communicative links between colony and metropole. The passage of news between Charles Town and London could take anything between five and ten weeks depending on the winds, the likelihood of storms, and the vicissitudes of the season. ‘Advices’ from Jamaica normally took eight to eleven weeks, although in May 1780 news reached Britain's capital from the outer Antilles island of St Kitts in only six.

There were also environmental changes that were strictly speaking conjunctural. The demand for sugar, and the consequent development of the slave trade, brought new diseases to the Caribbean. Yellow fever, passed on by the Aedes aegypti whose range was rarely more than 100 metres, travelled across the Atlantic in the water casks of slave ships from western Africa.