| |
Boris Galitzin and his electromagnetic
seismograph.
Galitzin, an inventor and prince in the Russian Empire, was the
first to develop a seismometer based on electromagnetic induction
around 1906. A signal is generated from a mass wrapped in a coil
of wire, surrounded by a fixed magnet. As the Earth moves, the mass
moves in the magnet's magnetic field produced by the magnet, and
a voltage is produced in the coil of wire that can be measured and
recorded. As a bonus, the induced current in the coil produces a
secondary magnetic field that damps the motion of the mass in a
predictable and useful way. Up until this time, seismometer mass
motions were mechanically or optically transferred to a recording
system. Galitzin's electromagnetic design became the basis for seismic
instrumentation used through much of the past 100 years.
This rare photograph of Galitzin was brought back to Colorado School
of Mines Geophysics Professor Tom Boyd by a friend who discovered
it during a visit to Russia several years ago.
|
