Underwater Telegraph

Underwater telegraph, or submarine telegraphy, was the mid-nineteenth-century system of insulated cables laid on the seabed to carry electric signals between coasts. The first cross-Channel cable between England and France worked from 1851, insulated with gutta-percha, and the first durable transatlantic cable followed in 1866. The technology shrank message times between continents from weeks by ship to minutes, and the seabed cable network underpinned imperial and commercial communications until radio and later fiber-optic systems.