So it was that when the civil war in Kansas grew into the Civil War in the Union, after Lincoln's election to the presidency, the Middle West, dominated by its combined Puritan and German population, ceased to compromise, and turned the scale in favor of the North. The Middle West furnished more than one-third of the Union troops. The names of Grant and Sherman are sufficient testimony to her leadership in the field. The names of Lincoln and Chase show that the presidential, the financial, and the war powers were in the hands of the Middle West. If we were to accept Seward's own classification, the conduct of foreign affairs as well belonged to the same section; it was, at least, in the hands of representatives of the dominant forces of the section. The Middle West, led by Grant and Sherman, hewed its way down the Mississippi and across the Gulf States, and Lincoln could exult in 1863, "The Father of Waters again goes unvexed to the sea. Thanks to the great Northwest for it, nor yet wholly to them." In thus outlining the relations of the Middle West to the slavery struggle, we have passed over important extensions of settlement in the decade before the war. In these years, not only did the density of settlement increase in the older portions of the region, but new waves of colonization passed into the remoter prairies. Iowa's pioneers, after Indian cessions had been secured, spread well toward her western limits. Minnesota, also, was recruited by a column of pioneers. The treaty of Traverse de Sioux, in 1851, opened over twenty million acres of arable land in that State, and Minnesota increased her population 2730.7 per cent in the decade from 1850 to 1860.