In Narrative of the Life of Frederick Douglass, what do the conflicts between Douglass and Covey reveal about slavery's effects on slaves and masters?

The
section of the book that the question is referring to is chapters 9 and 10.  In chapter 9,
Douglass is with Master Thomas for 9 months.  At the end of those 9 months, Thomas has decided
that Douglass is too unruly to continue keeping around.  Thomas decides to "lend"
Douglass to Edward Covey for one year.  That's when chapter 10 begins. 

Covey
has made a name for himself as one of the area's best slave breakers.  Thomas believes that
Covey can "train" Douglass to be a better slave.  

Some slaveholders thought it not much loss to allow Mr. Covey to have their slaves one
year, for the sake of the training to which they were subjected, without any other
compensation.

Covey's methods of "training"
aren't exactly kind.  He basically resorts to merciless beatings of slaves until the slaves
learn to do as they're told no matter what. Being more of a city slave, Douglass is unfamiliar
with the work that Covey requires of him.  Instead of teaching Douglass, Covey just beats
him. 

I...