The seismograph is widely believed to have been invented by Zhang Heng, a scholar and polymath who was born in the first century A.D. during the Eastern Han Dynasty. The device is included in a ...

According to "History of Later Han Dynasty," Zhang Heng's seismograph was an urn-like instrument with a central pendulum. An Earth tremor would cause the pendulum to loose balance and activate a ...

According to the History of Later Han Dynasty (25-220 AD), Zhang Heng's seismograph was an urn-like instrument with a central pendulum. An earth tremor would cause the pendulum to loose balance ...