Other related topics at:
Bondage
248. America/Americans;  Freedom; 
Slavery
"How is it that we hear the loudest yelps for liberty
among the drivers of negroes?"
Johnson: Taxation No Tyranny
Link
249. Hereditary
Bondage;  Slavery
 "It
must be agreed that in most ages many countries have had part
of their inhabitants in a state of slavery;  yet it may be
doubted whether slavery can ever be supposed the natural
condition of man.  It is impossible not to conceive that men in
their original state were equal;  and very difficult to imagine
how one would be subjected to another but by violent compulsion. 
An individual may, indeed, forfeit his liberty by a crime;  but
he cannot by that crime forfeit the liberty of his children. 
What is true of a criminal seems true likewise of a captive.  A
man may accept life from a conquering enemy on condition of
perpetual servitude;  but it is very doubtful  whether he can
entail that servitude on his descendants;  for o man can
stipulate without commission for another.  The condition which he
himself accepts, his son or grandson would have rejected."
"It
must be agreed that in most ages many countries have had part
of their inhabitants in a state of slavery;  yet it may be
doubted whether slavery can ever be supposed the natural
condition of man.  It is impossible not to conceive that men in
their original state were equal;  and very difficult to imagine
how one would be subjected to another but by violent compulsion. 
An individual may, indeed, forfeit his liberty by a crime;  but
he cannot by that crime forfeit the liberty of his children. 
What is true of a criminal seems true likewise of a captive.  A
man may accept life from a conquering enemy on condition of
perpetual servitude;  but it is very doubtful  whether he can
entail that servitude on his descendants;  for o man can
stipulate without commission for another.  The condition which he
himself accepts, his son or grandson would have rejected."
Boswell:  Life
Link
666. America; Freedom;  Slavery
"Slavery is now no where more patiently endured, than in
countries once inhabited by the zealots of liberty."
Johnson:  Idler #11 (June 24, 1758)
Link
1,820. Slavery
"Of black men the numbers are too great who are now repining
under English cruelty."
Johnson: Idler #87 (December 15, 1759)
Link