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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.
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."