The Kearney expedition of 1846, and the Bartlett and Williamson surveys in 1850 and 1853, demonstrated the practicability of reaching California by the southern route, and thousands of emigrants, attracted to the Pacific Coast by the discovery of gold, went that way in order to avoid the high mountains and the snow that they would have encountered further north. This rising tide of travel soon led to improvement in the means of transportation. Early in the “gold rush,” Dr. A. L. Lincoln, a relative of Abraham Lincoln, established a permanent ferry across the Colorado, near the junction of that river with the Gila; a few years later, seventy four camels and dromedaries were imported from Africa for use on the desert part of the route; and in 1857, a private company began running bimonthly stages between San Antonio, Texas, and San Diego, California. Finally, in 1858, the Government established the “Butterfield Overland Mail,” which ran a semi-weekly line of coaches from St. Louis to San Francisco, by way of El Paso, Yuma and the Colorado Desert, on a time schedule of twenty five days. This line was well equipped with more than a hundred specially constructed Concord coaches, a thousand horses, seven hundred mules, and about one hundred and fifty drivers. It received from the Government a subsidy of $600,000 a year, and was the longest continuous horse-express line then in existence on the North American continent. Until the outbreak of the Civil War, this southern route was the main artery of travel from the eastern States to the Pacific Coast; and it is estimated that, between 1849 and 1860, eight thousand emigrants crossed the Colorado Desert on their way to California.