The laying of an undersea telegraph cable, courtesy of a silent 1927 movie called “A Film Lesson in General Science: Communication.”
The first working undersea telegraph cables were laid across the English Channel in 1851. The first successful transatlantic cable was laid from 1854 to 1858. When it was complete it lowered the time to send a message from Europe to North America from a typical ship’s crossing of 10 days to a matter of minutes. Though one of the first messages sent, which contained 99 words, took almost 18 hours to send. The initial transmission speed across the wire was about two minutes per character.
From the Prelinger Archives.