<span>to show that slavery is a terrible practice that has brought misery to too many people
It's clear that he thinks far too many people have been made miserable by slavery when he says "</span><span>that so great a part of it", meaning that so many people of the world have been afflicted by slavery. It's also clear that he thinks it is a terrible practice, as he uses the phrases "bound in chains of darkness and in chains of misery". </span>
What do u need help with? Like there is just scribbles everywhere gotta be more specific