VINCENT PONKO JR.
Exploration and discovery are often integrally intertwined with the spirit of the period in which they occur. For instance, during the mid-1800s, a sense of mission to extend the influence of the United States and its value system was a pervasive factor in the outlook of U.S. government officials, explorers, and the American people. Whether or not it was called "Manifest Destiny," this perception that the United States would and should be a continental nation that was obligated to push its ideals abroad heavily conditioned the objectives and courses of official government exploration from the late 1830s to the beginning of the Civil War.
Previously, the exploration of what is now the western United States-- and the extension of American exploring activities to foreign shores in the name of "practical science"--had been largely a mechanism for private citizens of the Republic to expand their utilization of the rich resource base of the North American continent. With the exception of Jeffersonian exploration, in which expeditions like that of Meriwether Lewis and William Clark engaged in government-sponsored investigations, most exploration had been dominated by the commercial interests of the fur trade of the Rocky Mountains and farther West. The explorations of Manuel Lisa's men, of the Astorians, of William Henry Ashley's fur brigades, and of the largely unknown "free trappers" between 1806 and 1842 had not been primarily motivated by national policy (although that policy may ultimately have been shaped by those explorations). By the end of the fur trade era, however, private and commercial interests gave way to national objectives, in particular three desires: to increase the international scientific and philosophical significance of the Republic in the Americas and elsewhere through the application of Humboldtean rather than Enlightenment principles of scientific exploration; to expand American political and economic influence and control not just over the entire continent as far as the Pacific but to island