The Amphibious Expansion of a
Horsepower Steam Engine
AND RAILROADS IN RUSSIA
During the 1830s, increasing numbers of Americans moved into Texas and Oregon. In the 1840s, these two areas plus one-third of Mexico were annexed to the United States. The nation's territory increased by more than 50 percent to about three million square miles. At the same time, the amphibious Americans, who were moving on sea as well as land, sealed their first formal trade and diplomatic agreements with China. Henry David Thoreau, the philosopher of Walden Pond, observed Americans spreading out over continents and ocean as if "we have the Saint Vitus dance." Half a century later, at the height of British power, Lord Salisbury advised students who wished to understand England's history to use very large maps. The same advice could have been given in the 1830s and 1840s to observers of American history.
These decades mark the zenith of U.S. Manifest Destiny. The term appeared, appropriately, in mid-1845, when a Democratic editor, John