But the more marked and important change had been in the value of slave labor.

In 1789 the slaves produced little or no surplus, and in many States were regarded as a burden.

In 1860 they produced a surplus of at least three hundred millions of dollars.

The power of agricultural production in the Southern States had apparently no limit.

If the institution of Slavery could be rendered secure, the dominant minds of the South saw political power and boundless wealth within their grasp.