From what has been already said of the difficulties which Humboldt encountered before he obtained permission to enter the Spanish possessions in America, we may judge with what jealous suspicion the arrival of strangers in Colorado was regarded. Pike was surrounded by a detachment of Spanish soldiers, made prisoner with all his men, and taken to Santa Fe. Their ragged garments, emaciated forms, and generally miserable appearance did not speak much in their favour, and the Spaniards at first took the Americans for savages. However, when the mistake was recognized, they were escorted across the inland provinces to Louisiana, arriving at Natchitoches on the 1st July, 1807. The unfortunate end of this expedition cooled the zeal of the government, but not that of private persons, merchants, and hunters, whose numbers were continually on the increase. Many even completely crossed the American continent from Canada to the Pacific. Amongst these travellers we must mention Daniel William Harmon, a member of the North-West Company, who visited Lakes Huron and Superior, Rainy Lake, the Lake of the Woods, Manitoba, Winnipeg, Athabasca, and the Great Bear Lake, all between N. lat. 47 degrees and 58 degrees, and reached the shores of the Pacific. The fur company established at Astoria at the mouth of the Columbia also did much towards the exploration of the Rocky Mountains. Four associates of that company, leaving Astoria in June, 1812, ascended the Columbia, crossed the Rocky Mountains, and following an east-south-east direction, reached one of the sources of the Platte, descended it to its junction with the Missouri, crossed a district never before explored, and arrived at St. Louis on the 30th May, 1813. In 1811, another expedition composed of sixty men, started from St. Louis and ascended the Missouri as far as the settlements of the Ricara Indians, whence they made their way to Astoria, arriving there at the beginning of 1812, after the loss of several men and great suffering from fatigue and want of food. These journeys resulted not only in the increase of our knowledge of the topography of the districts traversed, but they also brought about quite unexpected discoveries. In the Ohio valley between Illinois and Mexico for instance, were found ruins, fortifications, and entrenchments, with ditches and a kind of bastion, many of them covering five or six acres of ground. What people can have constructed works such as these, which denote a civilization greatly in advance of that of the Indians, is a difficult problem of which no solution has yet been found. Philologists and historians were already regretting the dying out of the Indian tribes, who, until then, had been only superficially observed, and lamenting their extinction before their languages had been studied. A knowledge of these languages and their comparison with those of the old world, might have thrown some unexpected light upon the origin of the wandering tribes.[2]