==Slavery at the North== 
 the use of slave labor was important in the developement of the infrastructure in the so-called "Free States." Whatever can this be thinking of? The North had abolished slavery (immediately or gradually) by 1808 because it had no economic importance there; the infrastructure was still dirt roads by then.  8 July 2005 17:56 (UTC) 

 (All Northern states abolished slavery. Some declared that all slaves born after a certain date would be free, so slavery took some time to die out.)