Transatlantic telegraph cable

Transatlantic telegraph cables were undersea cables running under the Atlantic Ocean for telegraph communications. Telegraphy is a largely obsolete form of communication, and the cables have long since been decommissioned, but telephone and data are still carried on other transatlantic telecommunications cables.

The Atlantic Telegraph Company led by Cyrus West Field constructed the first transatlantic telegraph cable. The project began in 1854 with the first cable laid from Valentia Island off the west coast of Ireland to Bay of Bulls, Trinity Bay, Newfoundland. The first communications occurred on August 16, 1858, but the line speed was poor. The first official telegram to pass between two continents that day was a letter of congratulations from Queen Victoria of the United Kingdom to President of the United States James Buchanan. Signal quality declined rapidly, slowing transmission to an almost unusable speed. The cable was destroyed after three weeks when Wildman Whitehouse applied excessive voltage to it while trying to achieve faster operation. It has been argued that the cable's faulty manufacture, storage and handling would have caused its premature failure in any case. Its short life undermined public and investor confidence and delayed efforts to restore a connection.

The second cable was laid in 1865 with improved material. It was laid from the ship SS Great Eastern, built by John Scott Russell and Isambard Kingdom Brunel and skippered by Sir James Anderson. More than halfway across, the cable broke, and after many rescue attempts, it was abandoned. In July 1866 a third cable was laid from The Anglo-American Cable house on the Telegraph Field, Foilhommerum. On July 13, Great Eastern steamed westward to Heart's Content, Newfoundland, and on July 27 the successful connection was put into service. The 1865 cable was also retrieved and spliced, so two cables were in service. These cables proved more durable. Line speed was very good, and the slogan "Two weeks to two minutes" was coined to emphasize the great improvement over ship-borne dispatches. The cables altered the personal, commercial and political relations between people across the Atlantic. Since 1866, there has been a permanent cable connection between the continents.

In the 1870s, duplex and quadruplex transmission and receiving systems were set up that could relay multiple messages over the cable. Before the first transatlantic cable, communications between Europe and the Americas had occurred only by ship and could be delayed for weeks by severe winter storms. By contrast, the transatlantic cable made possible a message and response on the same day.

In the 1840s and 1850s several people proposed or advocated construction of a telegraph cable across the Atlantic, including Edward Thornton and Alonzo Jackman.

As early as 1840 Samuel F. B. Morse proclaimed his faith in the idea of a submarine line across the Atlantic Ocean. By 1850 a cable was run between England and France. That year, Bishop John T. Mullock, head of the Catholic Church in Newfoundland, proposed a telegraph line through the forest from St. John's to Cape Ray and cables across the Gulf of St. Lawrence from Cape Ray to Nova Scotia across the Cabot Strait.

Around the same time, a similar plan occurred to Frederic Newton Gisborne, a telegraph engineer in Nova Scotia. In the spring of 1851 he procured a grant from the Newfoundland legislature and, having formed a company, began building the landline.

In 1854, businessman and financier Cyrus West Field and Gisborne discussed the project. Afterward, Field considered the idea that the cable to Newfoundland could be extended across the Atlantic Ocean.