I was actually curious how the Solar Coronal event of 1859 known as the Carrington Event affected the telegraph system. Wiki does not seem to have much detail of this but there is mention of it in a number of historical documents.
Was the telegraph powered by large batteries and I am curious if the effect of the storm was one of temporary disruption or was there physical damage to the electrical connections or other components that would have caused them to be replaced or repaired ?
Google really is your friend.
history.com says
E.W. Culgan, a telegraph manager in Pittsburgh, reported that the resulting currents flowing through the wires were so powerful that platinum contacts were in danger of melting and “streams of fire” were pouring forth from the circuits. In Washington, D.C., telegraph operator Frederick W. Royce was severely shocked as his forehead grazed a ground wire. According to a witness, an arc of fire jumped from Royce’s head to the telegraphic equipment. Some telegraph stations that used chemicals to mark sheets reported that powerful surges caused telegraph paper to combust.
On the morning of September 2, the magnetic mayhem resulting from the second storm created even more chaos for telegraph operators. When American Telegraph Company employees arrived at their Boston office at 8 a.m., they discovered it was impossible to transmit or receive dispatches. The atmosphere was so charged, however, that operators made an incredible discovery: They could unplug their batteries and still transmit messages to Portland, Maine, at 30- to 90-second intervals using only the auroral current.
Wired wrote
On Sept. 2, 1859, at the telegraph office at No. 31 State Street in Boston at 9:30 a.m., the operators' lines were overflowing with current, so they unplugged the batteries connected to their machines, and kept working using just the electricity coursing through the air.When a geomagnetic storm hits the Earth, it shakes the Earth's magnetosphere.[...] As the magnetized plasma pushes the Earth's magnetic field lines around, currents flow. Those currents have their own magnetic fields and soon, down at the ground, strong electromagnetic forces are in play. In other words, your telegraph can run on "auroral current."
