Sorry, but I'm on a roll, and the more I read the more I suspect some of the info provided above is nonsense (Newton only captained two voyages, only six slaves ever died on his ships. Sources please.

"Newton later recalled that routinely a quarter of his captives, sometimes as many as half, would not survive the trip across the Atlantic. But there were vast profits to be made from the sale of those who did survive." This is also from a pro-Newton site.