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400 years after the creation of the original seismograph by Zhang Heng, it dissapears and is never seen again
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Italian Scientists develop a way of detecting tremors in the ground. A cup filled with mercury was used to do this.
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Luigi Palmeri, an Italian scientists make his own seisometer. It consists of sevral U-Shaped tubes filled with mercury, pointing in different directions. When the ground shook, the motion of the mercury stopped a clock simultaneously to start a recording drum, on which the motion of a float on the surface of mercury was registered
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The Japanese Seismological Society is founded by Sir James Alfred Ewig, Thomas Gray and John Milne.
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European scientists build on Zhang Heng's idea and make their own seismograph.
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After World War II, many advancements are made on the horizontal pendulum seismograph by Sir Ewing. This final seismograph is called the Press - Ewing Seismograph and is used throughout the world.
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Zhang Heng creates the Ancient Chinese Seismograph
