Up to this point the white race in the two sections had dealt with slavery by methods which were simply divergent, not antagonistic. It was true that the percentage of slaves in the total population had been very rapidly decreasing in the North and not in the South, and that the gradual abolition of slavery was proceeding in the North alone, and that with increasing rapidity. But there was no positive evidence that the South was bulwarked in favor of slavery; there was no certainty but that the South would in its turn and in due time come to the point which the North had already reached, and begin its own abolition of slavery. The language of Washington, Jefferson, Madison, Henry, and Mason, in regard to the evils or the wickedness of the system of slavery, was too strong to be heard with patience in the South of after years; and in this section it seems to have been true, that those who thought at all upon the subject hoped sincerely for the gradual abolition of slavery in the South. The hope, indeed, was rather a sentiment than a purpose, but there seems to have been no good reason, before 1793, why the sentiment should not finally develop into a purpose. All this was permanently changed, and the slavery policy of the South was made antagonistic to, and not merely divergent from, that of the North, by the invention of Whitney's saw gin for cleansing cotton in 1793. It had been known, before that year, that cotton could be cultivated in the South, but its cultivation was made unprofitable, and checked by the labor required to separate the seeds from the cotton. Whitney's invention increased the efficiency of this labor hundreds of times, and it became evident at once that the South enjoyed a practical monopoly of the production of cotton. The effect on the slavery policy of the South was immediate and unhappy. Since 1865, it has been found that the cotton monopoly of the South is even more complete under a free than under a slave labor system, but mere theory could never have convinced the Southern people that such would be the case. Their whole prosperity hinged on one product; they began its cultivation under slave labor; and the belief that labor and prosperity were equally dependent on the enslavement of the laboring race very soon made the dominant race active defenders of slavery. From that time the system in the South was one of slowly but steadily increasing rigor, until, just before 1860, its last development took the form of legal enactments for the re-enslavement of free negroes, in default of their leaving the State in which they resided. Parallel with this increase of rigor, there was a steady change in the character of the system. It tended very steadily to lose its original patriarchal character, and take the aspect of a purely commercial speculation. After 1850, the commercial aspect began to be the rule in the black belt of the Gulf States. The plantation knew only