At the time when the Declaration of Independence was drawn up and signed, one thing seemed to every American more important than anything else: that the country should be united in one whole. North and South must join together; no difference could outweigh a common nationality. The Southerners would not join the Union unless they were allowed to keep their slaves: therefore the Northerners left slavery in the South. They hoped, however, that it would gradually die out; and therefore a law was passed which declared that after twenty years no more slaves were to be brought from Africa. When Southerners declared, as they very often did, that slaves were very well treated, that they were much happier and more comfortable than if they were free, this was true to a certain extent. Those slaves who were employed in the houses and gardens of their masters, those who were used as servants, were often very well treated. But however well they were treated, it is wrong for a man to have other men entirely in his power; wrong for him, and wrong for them. And although some masters did not abuse their power, some did--and all could, if ever they wanted to--without feeling that they were doing anything wrong. A white gentleman could beat his black slave to death if he chose; he would not be punished any more than if he beat a dog to death, and his friends would still think him a gentleman. Moreover, far the greater number of the slaves were not used as servants, but used as labourers on the cotton plantations. Here they were under the charge of an overseer. His one idea was to get as much work out of them as possible. They worked all day, and at night were often herded together in any sort of shed. After Eli Whitney, a young American, invented a machine called the cotton gin, by using which one negro could pick twenty times as much cotton in a day as before, the business of working the cotton plantations with slaves made the Southern landowners very rich. Slaves were cheap: in a few days they made as much for their masters as they cost them, and their masters could make them work as hard as they liked. They were quite ignorant: their masters taught them nothing; they had no way of escape; they were absolutely at the mercy of the overseer with his whip. The masters came to regard these black fellow-beings simply as property: not so valuable as a horse, rather more useful than a dog; they often forgot that they had any feelings. Children were sold away from their parents; a husband was sent to one plantation, and his wife to another. They were sometimes beaten for the smallest fault. If they tried to escape, bloodhounds were used to hunt them down. Dealers led them about in chains, and sold them in the public market exactly like animals. People who came from the North to the South, as Abraham Lincoln did, on his trip down the Ohio, and saw how the slaves were treated, were often shocked; but in the South people were used to it.