https://en.wikipedia.org/wiki/Carrington_Event
Telegraph systems all over Europe and North America failed, in some cases giving telegraph operators electric shocks.[22] Telegraph pylons threw sparks.[23] Some telegraph operators could continue to send and receive messages despite having disconnected their power supplies.[24]
Some telegraph lines seem to have been able to produce a sufficient geomagnetically induced current from the electromagnetic field to allow for continued communication with the telegraph operator power supplies switched off.[25] The following conversation occurred between two operators of the American Telegraph Line between Boston and Portland, Maine, on the night of 2 September 1859 and reported in the Boston Traveler:
Boston operator (to Portland operator): "Please cut off your battery [power source] entirely for fifteen minutes."
Portland operator: "Will do so. It is now disconnected."
Boston: "Mine is disconnected, and we are working with the auroral current. How do you receive my writing?"
Portland: "Better than with our batteries on. – Current comes and goes gradually."
Boston: "My current is very strong at times, and we can work better without the batteries, as the aurora seems to neutralize and augment our batteries alternately, making current too strong at times for our relay magnets. Suppose we work without batteries while we are affected by this trouble."
Portland: "Very well. Shall I go ahead with business?"
Boston: "Yes. Go ahead."
The conversation was carried on for around two hours using no battery power at all and working solely with the current induced by the aurora, and it was said[by whom?] that this was the first time on record that more than a word or two was transmitted in such manner.[26]
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