ON THIS DAY: 27 July 1866 – History was made when the first working transatlantic telegraph cable came ashore at Heart’s Content, Newfoundland. While this original telegraph cable has long since become obsolete, its legacy lives on in the modern transatlantic cables that now carry telephone and internet data between continents.
The journey to success was anything but smooth. The first attempt to lay a transatlantic cable began in 1854, led by American entrepreneur Cyrus West Field and the Atlantic Telegraph Company. In 1858 a cable was laid between Valentia Island, off the coast of Ireland, and Trinity Bay, Newfoundland. It worked—but just barely. The signal was painfully slow, and although Queen Victoria and U.S. President James Buchanan exchanged congratulatory telegrams, the cable failed within three weeks. The cause? Excessive voltage applied in a desperate bid to increase speed.
A second effort came in 1865, this time using the SS Great Eastern, the largest ship of its day. Built by the legendary Isambard Kingdom Brunel and John Scott Russell, the massive iron-hulled steamship set out to lay a more reliable line. But disaster struck mid-ocean: the cable snapped and attempts to recover it failed. The mission was abandoned—temporarily.
Determined not to give up, the team returned in 1866. On July 27, after successfully laying 1,686 miles of cable from Telegraph Field in Foilhommerum, Valentia Island, the SS Great Eastern finally delivered a stable and fully operational transatlantic link to Heart’s Content. The team even managed to recover and complete the abandoned 1865 cable, which served as a backup line.
This new connection was not only durable but also fast by the standards of the time—marking the dawn of global real-time communication.
Progress didn’t stop there. In 1872, the Duplex transmission system—developed by Jean-Maurice-Émile Baudot and refined by Joseph Barker Stearns—revolutionised telegraphy by enabling two messages to be sent simultaneously. Then in 1874, Thomas Edison introduced the Quadruplex system, allowing four messages (two in each direction) to be transmitted at once over a single wire using variations in signal polarity and current strength.
The laying of the 1866 cable was a triumph of engineering, persistence, and vision—and it laid the foundation for the interconnected world we live in today.