The older States, however, had found, by this time, that the foreign and home demand for cotton was so rapidly increasing that there was little danger of over-production; and that they had, in fact, secured to themselves the monopoly of the foreign markets. Beside this, the abolition movement at that moment, had assumed its most threatening aspect, and was demanding the destruction of slavery or the dissolution of the Union. Here was a double motive operating to produce harmony in the ranks of Southern politicians, and to awaken the fears of many, North and South, for the safety of the Government. Here, also, was the origin of the determination, in the South, to extend slavery, by the annexation of territory, so as to gain the political preponderance in the National Councils, and to protect its interests against the interference of the North. It was not the increased demand for cotton, alone, that served as a protection to the older States. The extension of its cultivation, in the degree demanded by the wants of commerce, could only be effected by a corresponding increased supply of provisions. Without this, it could not increase, except by enhancing their price to the injury of the older States. This food did not fail to be in readiness, so soon as it was needed. Indeed, much of it had long been awaiting an outlet to a profitable market. Its surplus, too, had been somewhat increased by the Temperance movement in the North, which had materially checked the distillation of grain. The West, which had long looked to the East for a market, had its attention now turned to the South, as the most certain and convenient mart for the sale of its products--the planters affording to the farmers the markets they had in vain sought from the manufacturers. In the meantime, steamboat navigation was acquiring perfection on the Western rivers--the great natural outlets for Western products--and became a means of communication between the Northwest and the Southwest, as well as with the trade and commerce of the Atlantic cities. This gave an impulse to industry and enterprise, west of the Alleghanies, unparalleled in the history of the country. While, then, the bounds of slave labor were extending from Virginia, the Carolinas, and Georgia, Westward, over Tennessee, Alabama, Mississippi and Arkansas, the area of free labor was enlarging, with equal rapidity, in the Northwest, throughout Ohio, Indiana, Illinois and Michigan. Thus, within these provision and cotton regions, were the forests cleared away, or the prairies broken up, simultaneously by those old antagonistic forces, opponents no longer, but harmonized by the fusion of their interests--the connecting link between them being the steamboat. Thus, also, was a _tripartite alliance_ formed, by which the Western Farmer, the Southern Planter, and the English Manufacturer, became united in a common bond of interest: the whole giving their support to the doctrine of Free Trade.