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Monday, February 25, 2008

Who designed the first modern seismograph?


Who designed the first modern seismograph?

A seismograph is a sensitive instrument that records the seismic waves or vibrations, caused by earthquake. John Milne was the English seismologist and geologist who invented the first modern seismograph, and promoted the building of seismological stations. In 1880, three British scientists working in Japan, Sir James Ewing, Thomas Gray, and John Milne began to study earthquakes. They founded the Seismological Society of Japan. The society funded the invention of seismographs. Milne invented the horizontal pendulum seismograph in 1880. Around 132 AD, a Chinese scientist Chang Heng, invented the first seismoscope an instrument that could register the occurrence of an earthquake. Heng’s invention, ‘the dragon jar’ was a cylindrical jar with eight dragon heads arranged around its brim. Each dragonhead had a ball in its mouth. Around the foot of the jar were eight frogs, each directly beneath a dragonhead. During an earthquake, a ball dropped from a dragon’s mouth, and was caught by the frog.

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