First transcontinental telegraph
The first transcontinental telegraph (completed in 1861) was a line that connected an existing network in the eastern United States to a small network in California by a link between Omaha and Carson City via Salt Lake City. It was a milestone in electrical engineering and in the formation of the United States of America. It served as the only method of near-instantaneous communication between the east and west coasts during the 1860s. In 1841, it had taken 110 days for the news of the death of President Harrison to reach Los Angeles.
After the development of efficient telegraph systems in the 1830s, their use saw almost explosive growth in the 1840s. Samuel Morse's first experimental line between Washington, D.C. and Baltimore - the Baltimore-Washington telegraph line - was demonstrated on May 24, 1844. By 1850 there were lines covering most of the eastern states, and a separate network of lines was soon constructed in the booming economy of California.
California was also admitted to the United States in 1850, the first state on the Pacific coast. Major efforts ensued to integrate California with the other states, including sea and overland mail and passenger service. Proposals for the subsidy of a telegraph line to California were made in Congress throughout the 1850s, and in 1860 the U.S. Post Office was authorized to spend $40,000 per year to build and maintain an overland line. The year before, the California State Legislature had authorized a similar subsidy of $6,000 per year.
Construction of the first transcontinental telegraph was the work of Western Union, which Hiram Sibley and Ezra Cornell had established in 1856 by merging companies operating east of the Mississippi River. A second significant step was the passing of the Telegraph Act by the Congress in 1860, which authorized the government to open bids for the construction of a telegraph line between Missouri and California and regulated the service to be provided. Eventually, the only bidder would be Sibley, because all competitors—Theodore Adams, Benjamin Ficklin and John Harmon—withdrew at the last minute. Later they joined Sibley in his effort.
Similar to the First Transcontinental Railroad, elimination of the gap in the telegraph service between Fort Kearny in Nebraska and Fort Churchill in Nevada was planned to be divided between teams that would be advancing the construction in opposite directions. James Gamble, an experienced telegraph builder in California was put in charge of the western crew and Edward Creighton was responsible for the eastern crew. From Salt Lake City, a crew in charge of James Street advanced westward and a W.H. Stebbins’s grew toward Fort Kearny. Creighton’s crew erected its first pole on 4 July 1861. When the project was completed in October 1861, they have planted 27,500 poles holding 2,000 miles of single-strand iron wire over a terrain that was not always inviting. California Chief Justice Stephen Field sent one of the first messages from San Francisco to Abraham Lincoln, using the occasion to assure to the president the California allegiance to the Union. Note that the construction took place while Civil War fighting was taking place to the southeast. The entire cost of the system was half a million dollars.
Difficulties did not stop with the completion of the project. Keeping it in operation faced multiples problems: (a) inclement weather in the form of lightning bolts, strong winds and heavy snow damaged both poles and the wire; (b) rubbing on the poles by bisons sent down from time to time sections of the telegraph, eventually contributing to their demise; (c) the system has to be rerouted through Chicago to avoid attempts to cut the line in Missouri to disrupt communications among Union forces; (d) Native Americans soon started to do the same further west as part of the hostilities with the Army. 
Financially, the First Transcontinental Telegraph was a big success from the beginning. The charge during the first week of operation was a dollar a word, which was higher than the 30 cents specified by the Telegraph Act of 1860.
The telegraph line immediately made the Pony Express obsolete, and it officially ceased operations two days later. The overland telegraph line was operated until 1869, when it was replaced by a multi-line telegraph that had been constructed alongside the route of the First Transcontinental Railroad.
- Australian Overland Telegraph Line, a north-south Australian telegraph line completed in 1872
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