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Interesting fact of the day: The same effect that cuased light in a prism to split up into different colors is what ultimately caused the first transatlantic telegraphic wire in 1858 to fail.
Morse code is transmitted as on-off signals, effectively square waves. Square waves are in fact made up of many different frequencies. Like in a prism different frequencies move at different speeds through a wire. Therefore as the on-off pulses traveled through the transatlantic telegraph wire the signal spread out like it does in a prism and ultimately the pulses would overlap and be indistinguishable.
The effect was so extreme that it took a message of only 98 words (the first message sent) over 67 minutes to send one way and a whopping 16 hours to confirm the message.
Whitehouse, a doctor with little mathematical understanding, thought he could solve the problem by increasing voltage, which we now know was a futile effort. He increased the voltage to the point he managed to short out the cable entirely and made it useless. However Lord Kelvin had already warned of the problem as was ignored and he came up with the law of squares to describe the problem which later was refined to give us the telegraphers equation. The telegraphers equation is still used today to model feedlines in radio transmitters and receivers.
@freemo @Science I recently read a book on transatlantic telegraph history. The actual history was more complicated than the popular story, but far more interesting.
1. The cable didn't fail immediately like a bad comedy after Whitehouse turned the voltage up the dial to eleven. Instead, it failed at some point in the middle of multiple experiments, in which both Lord Kelvin and Whitehouse's devices were used.
2. While it's true that Whitehouse's HV transmitter certainly accelerated the cable failure, but even without him, the cable would likely fail soon as well. Submarine cables at that time suffered multiple engineering and quality control problems, especially, the quality of the dielectric insulation. Other cables from the same era, like the Red Sea Cable, also failed quickly. In fact, Whitehouse likely just triggered an insulation defect, a defect-free cable should've survived that voltage. In this sense, Whitehouse was a scapegoat in the telegraphy industry.
@niconiconi @freemo @Science I could've sworn I read somewhere years ago that "Hello World" truncated at "Hello Wo" before failure, but cannot find that source again. Anyone know if this true?
