In this race the free States, by reason of their greater population, wealth, and commercial enterprise, would have outstripped the South but for the introduction of a new and powerful influence which operated exclusively in favor of the latter. This was the discovery of the peculiar adaptation of the soil and climate of portions of the Southern States, combined with cheap slave-labor, to the cultivation of cotton. Half a century of experiment and invention in England had brought about the concurrent improvement of machinery for spinning and weaving, and of the high-pressure engine to furnish motive power. The Revolutionary war was scarcely ended when there came from the mother- country a demand for the raw fiber, which promised to be almost without limit. A few trials sufficed to show Southern planters that with their soil and their slaves they could supply this demand with a quality of cotton which would defy competition, and at a profit to themselves far exceeding that of any other product of agriculture. But an insurmountable obstacle yet seemed to interpose itself between them and their golden harvest. The tedious work of cleaning the fiber from the seed apparently made impossible its cheap preparation for export in large quantities. A negro woman working the whole day could clean only a single pound. [Illustration: JAMES K. POLK.] [Sidenote: Memoir of Eli Whitney, "American Journal of Science," 1832.] It so happened that at this juncture, November, 1792, an ingenious Yankee student from Massachusetts was boarding in the house of friends in Savannah, Georgia, occupying his leisure in reading law. A party of Georgia gentlemen from the interior, making a visit to this family, fell into conversation on the prospects and difficulties of cotton- culture and the imperative need of a rapidly working cleaning-machine. Their hostess, an intelligent and quick-witted woman, at once suggested an expedient. "Gentlemen," said Mrs. Greene, "apply to my young friend, Mr. Eli Whitney; he can make anything." The Yankee student was sought, introduced, and had the mechanical problem laid before him. He modestly disclaimed his hostess's extravagant praises, and told his visitors that he had never seen either cotton or cotton- seed in his life. Nevertheless, he went to work with such earnestness and success, that in a few months Mrs. Greene had the satisfaction of being able to invite a gathering of gentlemen from different parts of the State to behold with their own eyes the working of the newly invented cotton-gin, with which a negro man turning a crank could clean fifty pounds of cotton per day. [Sidenote: 1808.] [Sidenote: Compendium, Eighth Census, p. 13.]