Yet, in 1850 nearly all the railroads in the United States lay east of the Mississippi River, and all of them, even when they were physically mere extensions of one another, were separately owned and separately managed.

The construction of extensive railways, however, and particularly the consolidation of small, experimental lines into large systems, dates from the days of the discovery of gold in California

When the scheme for the construction of a railroad from Baltimore to the waters of the Ohio River first began to take form, the United States had barely emerged from the Revolutionary period

Yet, in 1850 nearly all the railroads in the United States lay east of the Mississippi River, and all of them, even when they were physically mere extensions of one another, were separately owned and separately managed.

People began to understand that with the acquisition of California the nation had obtained practically half a continent, of which the future possibilities were almost unlimited, so far as the development of natural resources and the genera production of wealth were concerned.

Horses and mules, and even sail cars, made more rapid progress than did the earliest locomotive.

The United States as we know it today is largely the result of mechanical inventions, and in particular of agricultural machinery and the railroad. One transformed millions of acres of uncultivated land into fertile farms, while the other furnished the transportation which carried the crops to distant markets.