The Thirteen States whose independence had been acknowledged by George III., occupied with their outlying territories a vast area, exceeding in the aggregate eight hundred thousand square miles. Extended as was this domain, the early statesmen of the Union discovered that its boundaries were unsatisfactory,--hostile to our commercial interests in time of peace, and menacing our safety in time of war. The Mississippi River was our western limit. On its farther shore, from the Lake of the Woods to the Balize, we met the flag of Spain. Our southern border was the 31st parallel of latitude; and the Spanish Floridas, stretching across to the Mississippi, lay between us and the Gulf of Mexico. We acquired from Spain the right of deposit for exports and imports at New Orleans, but the citizens of the Union who lived west of the Alleganies were discontented and irritated to find a foreign power practically controlling their trade by intercepting their access to the sea. One of the great problems imposed upon the founders of the Union was to remove the burdens and embarrassments which obstructed the development of the Western States, and thus to render their inhabitants as loyal by reason of material prosperity as they already were in patriotic sympathy. The opportunity for relief came from remote and foreign causes, without our own agency; but the courageous statesmanship which discerned and grasped the opportunity, deserved, as it has received, the commemoration of three generations. The boundaries of the Union were vastly enlarged, but the geographical change was not greater than the effect produced upon the political and social condition of the people. The ambitions developed by the acquisition of new territory led to serious conflicts of opinion between North and South,--conflicts which steadily grew in intensity until, by the convulsion of war, slavery was finally extinguished. TERRITORIAL CESSIONS IN AMERICA.