Wealth pure and simple. Slaves were the first "Black Gold" long before the discovery of a use for petroleum. The demand for slaves in the Americas, could make a handy profit. When they found out they could also turn a profit delivering sugar and rum to Europe, their profits doubled. By picking up trade good and Iron in Europe for delivery to Africa their profits trebeled. Two circuits and a crewman could buy a pub with his share and the Captain could buy a country home and retire for life.
