But is this seeming productiveness of slavery real, or is it only imaginary? Has the system such capacities, over the other industrial interests of the nation, in the creation of wealth, as these figures indicate? Or, are these results due to its intermediate position between the agriculture of the country and its foreign commerce? These are questions worthy of consideration. Were the planters left to grow their own provisions, they would, as already intimated, be unable to produce any cotton for export. That their present ability to export so extensively, is in consequence of the aid they receive from the North, is proved by facts such as these: In 1820, the cotton-gin had been a quarter of a century in operation, and the culture of cotton was then nearly as well understood as at present. The North, though furnishing the South with some live stock, had scarcely begun to supply it with provisions, and the planters had to grow the food, and manufacture much of the clothing for their slaves. In that year the cotton crop equaled 109 lbs. to each slave in the Union, of which 83 lbs. per slave were exported. In 1830 the exports of the article had risen to 143 lbs., in 1840 to 295 lbs., and in 1853 to 337 lbs. per slave. The total cotton crop of 1853 equaled 395 lbs. per slave--making both the production and export of that staple, in 1853, more than four times as large, in proportion to the slave population, as they were in 1820.[47] Had the planters, in 1853, been able to produce no more cotton, per slave, than in 1820, they would have grown but 359,308,472 lbs., instead of the actual crop of 1,305,152,800 lbs.; and would not only have failed to supply any for export, but have barely supplied the home demand, and been _minus_ the total crop of that year, by 945,844,328 lbs. In this estimate, some allowance, perhaps, should be made, for the greater fertility of the new lands, more recently brought under cultivation; but the difference, on this account, can not be equal to the difference in the crops of the several periods, as the lands, in the older States, in 1820, were yet comparatively fresh and productive.