On Slavery

An article in Slate suggests there were revolts on about ten per cent of the ships carrying enslaved people from Africa.

"....revolts (and the occasional attacks from the mainland on ships anchored off the African coast) truly impacted the profitability of the enterprise: “The threat of rebellion had a very real impact on costs. … Even unsuccessful revolts reduced the number of slaves carried off from Africa.”

It also reports that slavery remained in the supposedly free Northern States for a surprisingly long time

"As Harvey Amani Whitfield writes in his history of slavery in Vermont—a state that supposedly abolished the practice in 1777—the law was also unevenly and selectively enforced. Powerful people continued to hold servants in bondage 20 years after the passage of that state’s constitution."

A good read.