That the establishment at Astoria never flourished, as its founder hoped, is a well-known fact; but the heroic efforts made by the members of the two expeditions to carry out their instructions did much to pave the way for the colonization and civilization of the beautiful states of Oregon and Washington; and the numerous journeys, undertaken by Hunt, Mackenzie, and others among the various chains of the Rocky Mountains, though their main object was trade, justly entitle them to rank as pioneers of geographical discovery. To them, too, the United States Government, though scarcely our own, owes a debt of gratitude, their early occupation of Astoria having been a main point in the American claim to the Oregon territory, which at one time seemed likely to have become the property of Great Britain. CHAPTER XIII. THE MISSISSIPPI AND ITS CHIEF AFFLUENTS. WHILE the expeditions lately described were in progress, efforts were being made by private individuals to supplement the work of Lewis, Clarke, and Pike. The lower course of the Red River was explored from Natchez by Mr. Dunbar and Dr. Hunter, and its upper waters were navigated by Dr. Sibley from Natchitoches, but nothing further was done toward determining the true sources of the Mississippi itself, until 1820, when Governor Cass, then in charge of Michigan territory, obtained permission to visit the highlands of Minnesota, and the great expedition under Long and James was sent by the United States Government to trace the course of its mightiest affluent, the Missouri. Cass and his companions, accompanied by an escort of thirty-eight men, left Detroit, the capital of Michigan, in the spring of 1820, and made their way along the coasts of Lakes Huron and Superior to the borders of Minnesota, where they struck comparatively new ground, crossing the lovely basin of the St. Lawrence in a north-westerly direction, and reaching the shores of Sandy Lake in the middle of July. On the 17th of the same month, the canoes brought for the purpose were launched on the waters of the Mississippi, and the actual voyage of exploration began. The strong current of the mighty Father of Waters rendered the ascent extremely arduous, and after a struggle, extending over one hundred and fifty miles, a series of impassable cataracts were reached, necessitating the carrying of the canoes and baggage for a considerable distance overland.