Stephen A. Douglas said in 1859 it was his confident opinion that more than fifteen thousand slaves had been imported in the preceding year, and that the trade had been carried on extensively for a long while.[55] About 1860 it was stated that twenty large cities and towns in the South were depots for African slaves and sixty or seventy cargoes of slaves had been introduced in the preceding eighteen months.[56] It was estimated in 1860 that eighty-five vessels which had been fitted out from New York City during eighteen months of 1859 and 1860, would introduce from thirty thousand to sixty thousand annually.[57] From what has been said it seems to us certain that at least 270,000 slaves were introduced into the United States from 1808 to 1860 inclusive.[58] These we would distribute as follows: Between 1808 and 1820, sixty thousand; 1820 to 1830, fifty thousand; 1830 to 1840, forty thousand; 1840 to 1850, fifty thousand and from 1850 to 1860 seventy thousand. We consider these very moderate and even low estimates. It will be seen later that these figures are of prime importance in accounting for the presence of certain slaves in the States of the extreme South. FOOTNOTES: [Footnote 1: A. Helps: The Spanish Conquest of America, Vol. I., 30-32.] [Footnote 2: Ibid., 35-36.] [Footnote 3: Helps: Sp. Con. of Am., Vol. I., 40.] [Footnote 4: Edwards: British West Indies, Vol. II., 44. Brock: Va. Hist. So. Collection, Vol. VI., 2.] [Footnote 5: Edwards: British West Indies, Vol. II., 47-8.] [Footnote 6: Ballaugh: Hist. of Slavery in Va., p. 4.] [Footnote 7: John Smith: Hist. of Va., Vol. II., 39. Ballaugh: Hist. of Slavery in Va., pp. 8-9. There has been some misunderstanding as to the date, but Ballaugh makes it clear that 1619 is correct.] [Footnote 8: Brock: Va. Hist. So. Coll., VI., 9. Ballaugh: Hist. Sl. in Va., p. 9.] [Footnote 9: Hening: States at Large, Vol. II., 515.] [Footnote 10: Ballaugh: Hist. Sl. in Va., pp. 10-14.] [Footnote 11: Ibid., p. 19.] [Footnote 12: De Bow: Industrial Resources of the South, Vol. III., 130.] [Footnote 13: Scharf: Hist. of Md., Vol. I., 376-7.] [Footnote 14: N.C. Colonial Records, Vol. I., 693.] [Footnote 15: N.J. Archives, Vol. V., 152.] [Footnote 16: Du Bois: Suppression of Slave Trade, p. 5.] [Footnote 17: M'Call: Hist. of Ga., II., 125.] [Footnote 18: N.C. Colonial Records, Vol. II., p. 17.] [Footnote 19: Bassett: Slavery and Servitude in N.C., pages 20-22. In J.H.U. Studies, Vol. XIV.] [Footnote 20: Scharf: Hist. of Md., Vol. I., 376-7. N.C. Colonial Records, Vol. I., 693.] [Footnote 21: The Assiento was a treaty between England and Spain, by which Spain granted England a monopoly of the Spanish colonial slave trade for thirty years. Du Bois: Suppression of Slave Trade, p. 3.] [Footnote 22: Du Bois: Suppression of Slave Trade, p. 4-6.] [Footnote 23: Du Bois: Suppression of Slave Trade, Appendix A.] [Footnote 24: Ibid., pp. 4-5.] [Footnote 25: N.C. Col. Rec., Vol. V., 1118.]