FROM what has been said, the dullest intellect can not fail, now, to perceive the _rationale_ of the Kansas-Nebraska movement. The political influence which these Territories will give to the South, if secured, will be of the first importance to perfect its arrangements for future slavery extension--whether by divisions of the larger States and Territories, now secured to the institution, its extension into territory hitherto considered free, or the acquisition of new territory to be devoted to the system, so as to preserve the balance of power in Congress. When this is done, Kansas and Nebraska, like Kentucky and Missouri, will be of little consequence to slaveholders, compared with the cheap and constant supply of provisions they can yield. Nothing, therefore, will so exactly coincide with Southern interests, as a rapid emigration of freemen into these new Territories. White free labor, doubly productive over slave labor in grain-growing, must be multiplied within their limits, that the cost of provisions may be reduced and the extension of slavery and the growth of cotton suffer no interruption. The present efforts to plant them with slavery, are indispensable to produce sufficient excitement to fill them speedily with a free population; and if this whole movement has been a Southern scheme to cheapen provisions, and increase the ratio of the production of sugar and cotton, as it most unquestionably will do, it surpasses the statesman-like strategy which forced the people into an acquiescence in the annexation of Texas.