Once the slaves started having children, the demand for slaves dropped while the market for selling slaves and their children went up. This was another way they kept slaves in slavery. If a person was born to a slave, he or she was automatically born into a life of slavery. The owners would also keep their slaves ignorant. They would not teach them how to read or write. If they could read, they would have been shocked to find that these colonists believed that every man is born with the unalienable rights of life, liberty, and the pursuit of happiness. They also would have known that these colonists left the last country that they were in for this same reason. .
Their ignorance to this fact is not what kept them in slavery though. What kept them subservient was the fact that they knew they would be made an example of if they tried to escape.
Only a minority of the whites owned slaves, at all times nearly three-fourths of the white families in the South as a whole held no slaves. Slave ownership in the South was not widespread. Not more than a quarter of the white heads of families were slave owners, and even in the cotton states the proportion was less than one-third. In 1850, only one in three owned any Negroes. On the eve of the Civil War, the ration was one in four; and slave owners probably made up less than a third of southern whites. .
Not all blacks were slaves. There were a many number of free blacks, consisting of those had been freed or those in fact that were never slave. Nor did all slaves work on plantations. There were nearly five hundred thousand that worked in the cities as domestic, skilled artisans and factory hands. But they were exceptions to the general rule. Most blacks in America were slaves on plantation-sized units in the seven states of the South. And with the invent of the cotton gin by Eli Whitney, more slaves were needed to work the ever-growing cotton game. The size of the plantations varied with the wealth of the planters.