In 132 AD the Han dynasty scholar Zhang Heng, the court astronomer and a mathematician, presented to the emperor a bronze instrument, about two metres wide, shaped like a wine jar, with eight dragon heads around the rim, each holding a ball above a toad with an open mouth. When an earthquake shook the ground, an inner pendulum is thought to have made a lever open the jaw of the dragon that pointed toward the quake, dropping the ball into the toad with a clang. In 138 it is said to have signalled an earthquake in Gansu, 500 km away, that no one in the capital had felt. Modern seismographs only appeared in the 19th century.
Before and after
- c. 125 CEOrigins of Edirne
- 2nd centuryConstruction of Pantheon
- September 129 CEBirth of Galen
- from 132 CE to 136 CEBar Kokhba revolt
- 132 CEZhang Heng builds the first seismoscope
- 135 CEOrigins of Temple of Venus and Roma
- c. 135 CEConstruction of Castel Sant'Angelo
- 142 CEConstruction of Antonine Wall
- 142 CEOrigins of Temple of Antoninus and Faustina
More in Science & technology
- 4th century BCEElements
- c. 270s BCEAristarchus of Samos proposes that the Earth orbits the Sun
- 3rd century BCEArchimedes' principle
- c. 241 BCEEratosthenes measures the size of the Earth
- 1 January 45 BCEThe Julian calendar takes effect
- c. 150sPtolemy writes the Almagest
The era
This moment belongs to the Ancient civilizations (3,200 BCE to 500 CE), writing, cities and empires. You can also browse everything in the 2nd century.