from the United States between 1821 and 1830 was about thirty-three
million dollars, while all other domestic exports made a sum of but
twenty million dollars. [Footnote: Ibid., 518.] Even greater than
New England's interest in the carrying-trade was the interest of the
south in the exchange of her great staples in the markets of Europe.

Never in history, perhaps, was an economic force more influential
upon the life of a people. As the production of cotton increased,
the price fell, and the seaboard south, feeling the competition of
the virgin soils of the southwest, saw in the protective tariff for
the development of northern manufactures the real source of her
distress. The price of cotton was in these years a barometer of
southern prosperity and of southern discontent. [Footnote: See chap,
xix., below; M. B. Hammond, Cotton Industry, part i., App. i.;
Donnell, Hist. of Cotton; Watkins, Production and Prices of Cotton.]

Even more important than the effect of cotton production upon the
prosperity of the south was its effect upon her social system. This
economic transformation resuscitated slavery from a moribund
condition to a vigorous and aggressive life. Slowly Virginia and
North Carolina came to realize that the burden and expense of
slavery as the labor system for their outworn tobacco and corn
fields was partly counteracted by the demand for their surplus
Negroes in the cotton-fields of their more southern neighbors. When
the lower south accepted the system as the basis of its prosperity
and its society, the tendency in the states of the upper south,
except in the pine barrens and the hill country, to look upon the
institution as a heritage to be reluctantly and apologetically
accepted grew fainter. The efforts to find some mode of removing the
Negro from their midst gradually came to an end, and they adjusted