the vast western territories. The widespread circulation of important newspapers by mail, such as the New York Weekly Tribune, facilitated coordination among politicians in different states. The postal service helped to integrate already established areas with the frontier, creating a spirit of nationalism and providing a necessary infrastructure. The army early on assumed the mission of protecting settlers along with the Westward Expansion Trails, a policy that was described by Secretary of War John B. Floyd in 1857: A line of posts running parallel without frontier, but near to the Indians' usual habitations, placed at convenient distances and suitable positions, and occupied by infantry, would exercise a salutary restraint upon the tribes, who would feel that any foray by their warriors upon the white settlements would meet with prompt retaliation upon their own homes. There was a debate at the time about the best size for the forts with Jefferson Davis, Winfield Scott, and Thomas Jesup supporting forts that were larger but fewer in number than Floyd. Floyd's plan was more expensive but had the support of settlers and the general public who preferred that the military remain as close as possible. The frontier area was vast and even Davis conceded that "concentration would have exposed portions of the frontier to Native hostilities without any protection." Scientists, artists, and explorers Government and private enterprise sent many explorers to the West. In 1805–1806, Army lieutenant Zebulon Pike (1779–1813) led a party of 20 soldiers to find the headwaters of the Mississippi. He later explored the Red and Arkansas Rivers in Spanish territory, eventually reaching the Rio Grande. On his return, Pike sighted the peak in Colorado named after him. Major Stephen Harriman Long (1784–1864) led the Yellowstone and Missouri expeditions of 1819–1820, but his categorizing in 1823 of the Great Plains as arid and useless led to the region getting a bad reputation as the "Great American Desert", which discouraged settlement in that area for several decades. In 1811, naturalists Thomas Nuttall (1786–1859) and John Bradbury (1768–1823) traveled up the Missouri River documenting and drawing plant and animal life. Artist George Catlin (1796–1872) painted accurate paintings of Native American culture. Swiss artist Karl Bodmer made compelling landscapes and portraits. John James Audubon (1785–1851) is famous for classifying and painting in minute details 500 species of birds, published in Birds of America. The most famous of the explorers was John Charles Frémont