The Exposition at Philadelphia this year was a revelation to the United States. Though far surpassed by later "world's fairs," it displayed the wide resources of the United States and brought home the difference between American and European civilization. The foreign exhibits first had a chastening influence upon American exuberance, and then stimulated the development of higher artistic standards. In ingenuity the American mind held its own against all competition. But few Americans had traveled, the cheap processes of illustration were yet unknown, and in the resulting ignorance the United States had been left to its assumption of a superiority unjustified by the facts. From the centennial year may be dated the closer approach of American standards to those of the better classes of Europe. In the summer of 1876 the thirty-eighth State, Colorado, was added to the Union. It had been seventeen years since the miners thronged the Kansas and Nebraska plains, bound for "Pike's Peak or Bust!" In the interval the mining camps had become permanent communities. Authorized in 1864 to form a State, they had declined to accept the responsibility and had lingered for many years with only a handful of inhabitants. Now and then entirely isolated from the United States by Indian wars, they had prayed for the continental railroad, only to be disappointed when the Union Pacific went through Cheyenne instead of Denver. One of the branches of the Union Pacific was extended to Denver in 1870, and thereafter Colorado grew in spite of the panic of 1873. Grant began to urge its admission in his first Administration, and signed a proclamation admitting it in 1876. It came in in time to cast three Republican electoral votes in the most troublesome presidential contest the United States had seen. BIBLIOGRAPHICAL NOTE