Got something to say to this podcast? Send a voicemail, and you might hear yourself on the next episode!

The textbook triangle of the Atlantic slave trade, with single ships running from Europe to Africa to the Americas and home, rarely happened. Historian Herbert S. Klein’s work with maritime logs shows slave ships were built to pack captives and suited poorly to barrels and bales, so many sailed home with rocks, dirt or sand as ballast while separate fleets carried sugar, tobacco and cotton. A 2017 economic study found that a 1 percent increase in European gunpowder exports to Africa set off a cycle that raised exports of enslaved people by an average of 50 percent, as armed groups raided neighbors who then needed guns to defend themselves. New England merchants distilled Caribbean molasses into rum for West Africa on voyages averaging a year, financed by syndicates and credit reaching back to London.

Between about 1620 and 1709, New England and Newfoundland fishermen sold salted cod to Catholic Spain and Portugal for Lent and saints’ days, taking sack wine, olive oil, dried fruit and silver coin in return. When they began salting fish wet at sea to stay out longer, the result was refuse-grade cod that Iberian buyers rejected, so merchants sold it cheaply to Caribbean planters to feed enslaved workers, lowering plantation costs and feeding demand for more captives. The Emory University database counts 12.5 million people forced onto ships from 1450 to 1800, with 12 to 13 percent dying in the Middle Passage on average.

• About 4.8 million enslaved people were taken to Portuguese Brazil.
• Roughly 2.3 million went to the British Caribbean and 1.1 million to the French Caribbean.
• Only about 388,000 arrived directly in what is now the United States.
• Portugal transported nearly 6 million people and Great Britain over 3.2 million.
• Later trade triangles linked Cuban sugar to Baltic iron and hemp, and Australian coal to Chinese tea and silk.