Simple and Complex

Just Add Water?

If a wire could carry messages over land, could an insulated wire do the same under water? In practice, things turned out to be more complicated:


These problems and others had to be solved before underwater cables could work.




Underwater cable for Bering Strait, 1866 In addition to the problems caused by mixing water and electricity, underwater cables had to survive corrosion, barnacles, burrowing worms, and the occasional shark bite.

This cable was made for a proposed route between Siberia and Alaska, but the line was never laid.
Underwater cable for Bering Strait, 1866
National Museum of American History, from Isabelle Field Judson



William Thomson (Lord Kelvin), 1859 The great Scottish physicist William Thomson (later Lord Kelvin) (1824-1907) made underwater cables possible by solving many of the problems. He was aboard ship for all of the early transatlantic expeditions, and he designed sensitive receiving equipment to detect feeble and distorted telegraph pulses.
William Thomson (Lord Kelvin), 1859
From Agnes Gardner, Kelvin the Man, 1925
Smithsonian Institution Libraries



Letter from William Thomson to American cable promoter Cyrus Field, 1862 Letter from William Thomson to American cable promoter Cyrus Field, 1862
Letter from William Thomson to American cable promoter Cyrus Field, 1862
National Museum of American History, from Isabelle Field Judson



As a physicist, William Thomson combined brilliant mathematical analysis with hands-on practicality. His description of electrical action in a cable was difficult even for some physicists to follow, but he also invented devices that made the system work.
On the Theory of the Electric Telegraph On Practical Methods for Rapid Signaling by the Electric Telegraph
William Thomson, "On the Theory of the Electric Telegraph" (left, 1855) and "On Practical Methods for Rapid Signaling by the Electric Telegraph" (right, 1856), Proceedings of the Royal Society of London
Smithsonian Institution Libraries

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