NavList:

Here's a brief discussion of the induced currents:
http://en.wikipedia.org/wiki/Geomagnetically_induced_current

One thing to note here is that there are big currents in the ground and that may help explain what was going on in those old telegraph systems in 1859.

For some real enjoyment, visit Google Books and search on "telegraph" in books published during the 19th century. There are hundreds of books. Many of them speak in awe of the technology. It's like reading about the rise of the Internet today. Here's just one example:
"The Electric Telegraph has excited and is still exciting much interest over all the enlightened parts not only of this country, but of the world. No one can view the extensive lines, and hear of and see its wonderful, nay, magical effects, without a strong desire to become better informed of its history and mode of operation. Like every other branch of science, it has a history, a beginning, and a gradual advance to its present perfect state." (in 1853!)

You can follow the competition between various different signalling systems (Bain vs. Morse, for example) and different coding systems. We're all used to Morse code as the standard for telegraphy into the 20th century, but it took some decades for it all to shake out.

-FER
PS: Speaking of codes, many of you have been around computers long enough to know the expression "ASCII". Try this: go to google books and look up "ascii" in books published before 1900. You may be surprised to find it in books on astronomy and navigation. :)

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