The Telegraph and What It Wrought

I apologize for not screening the video The Transatlantic Cable last night. If you want a concise summary of the struggle to link North America with Europe via telegraph, read this unillustrated article from History magazine. It overlaps with the story of the American Experience documentary.

Speaking of the transatlantic cable, I misstated the number of attempts it took to finally successfully connect North America with Europe via cable in 1866. It took three attempts, not four.

Remember how the first cable largely failed because Wildman Whitehouse had sent too much voltage through the wire, which caused the insulation to break and ultimately fail? The solution that ultimately worked was proposed by William Thompson, later known as Lord Kelvin. He employed a mirror galvanometer to magnify the weak signal. It was also used to diagnose the cable when it was being laid to sea.

The boat that was ultimately used to law the third and ultimately successful transatlantic cable was the Great Eastern. I misspoke when I said that it was designed to go from the US to Australia. Actually, it was built to go from England to its penal colony in Oceania (or Australia).

For those wondering what it was like to send a telegram, I updated the slides to show a basic flow:

  1. Crafting a message
  2. Dictating at a local telegraph office
  3. Transcribing message to Morse Code
  4. Relay from one telegraph office to another
  5. Production of a telegram
  6. Dispatch of a delivery boy
  7. Final delivery of a message

You can also get a sense of this by watching certain movies made before World War II.

Finally, if you’re interested in see how your computer relays traffic from one computer to another, do a traceroute.