The North Employed Slaves as Soldiers (This is a URL)
This source is a correspondence between Robert E. Lee and Andrew Hunter. At the time of writing the Emancipation Proclamation has been in effect for some time now. Lee states that, in reference to black soldiers, " we should employ them without delay." This of course never happened and as the north got more and more territory in the south more slaves became free. Lee also states that if he were to only rely on the white population then he would be "overtaxing the capacity of our white population." By saying this he shows that the southern population isn't big nor strong enough to match the Norths economy and population especially without the help of slaves.