What was the first transatlantic telegraph cable?
Quick answer
The first transatlantic telegraph cable was laid by the Atlantic Telegraph Company, led by American businessman Cyrus Field, and completed on August 5, 1858. It ran about 3,200 km along the seabed from Valentia Island, Ireland, to Trinity Bay, Newfoundland. It worked for only about three weeks before failing.
A fragile success
The 1858 cable linked Europe and North America instantly for the first time. Before it, news crossed the Atlantic by ship, taking about 10 days.
The first official message, from Queen Victoria to US President James Buchanan, was 98 words long and took about 16 hours to transmit, because the signals were so weak. New York celebrated with fireworks, and a fire accidentally damaged City Hall.
Why it failed
The cable’s insulation was poor, and its chief electrician, Wildman Whitehouse, applied very high voltages to push signals through. Within a few weeks, the cable stopped working. Many people even suspected the whole thing had been a hoax.
Getting it right in 1866
| Attempt | Result |
|---|---|
| 1857 | Cable snapped during laying |
| 1858 | Worked for about three weeks |
| 1865 | Cable broke mid-ocean |
| 1866 | Permanent success; the lost 1865 cable was also recovered and completed |
The 1866 cables were laid by the Great Eastern, the largest ship of its time, designed by Isambard Kingdom Brunel. Physicist William Thomson (later Lord Kelvin) invented the sensitive mirror galvanometer to detect faint signals, and was knighted for his work.
Why it mattered
- Messages between London and New York took minutes instead of days.
- It transformed news, finance and diplomacy, an early step toward a connected world.
- Sending a message was expensive at first, about $1 per letter.
From telegraph to internet
Today, more than 500 fiber-optic undersea cables carry over 95% of international internet and phone traffic. They follow some of the same routes as the old telegraph lines.
For the invention that grew from the telegraph, see who invented the telephone. Electricity’s link to magnetism made these signals possible; see who discovered electromagnetic induction.
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