This solution of the last problem in cheap cotton-culture made it at once the leading crop of the South. That favored region quickly drove all competitors out of the market; and the rise of English imports of raw cotton, from thirty million pounds, in 1790 to over one thousand million pounds in 1860, shows the development and increase of this special industry, with all its related interests. [Footnote: The Virginia price of a male "field hand" in 1790 was $250; in 1860 his value in the domestic market had risen to $1600.--SHERRARD CLEMENS, speech in H. E. Appendix "Congressional Globe," 1860-1, pp. 104-5.] It was not till fifteen years after the invention of the cotton-gin that the African slave-trade ceased by limitation of law. "Within that period many thousands of negro captives had been added to the population of the South by direct importation, and nearly thirty thousand slave inhabitants added by the acquisition of Louisiana, hastening the formation of new slave States south of the Ohio River in due proportion." [Transcriber's Note: Lengthy footnote (1) relocated to chapter end.] It is a curious historical fact, that under the very remarkable material growth of the United States which now took place, the political influence remained so evenly balanced between the North and the South for more than a generation. Other grave issues indeed absorbed the public attention, but the abeyance of the slavery question is due rather to the fact that no considerable advantage as yet fell to either side. Eight new States were organized, four north and four south of the Ohio River, and admitted in nearly alternate order: Vermont in 1791, _free_; Kentucky in 1792, _slave_; Tennessee in 1796, _slave_; Ohio in 1802, _free_; Louisiana in 1812, _slave_; Indiana in 1816, _free_; Mississippi in 1817, _slave_; Illinois in 1818, _free_. Alabama was already authorized to be admitted with slavery, and this would make the number of free and slave States equal, giving eleven States to the North and eleven to the South.