Zhang Heng's seismoscope
Bronze dragons show where an earthquake has struck
The court astronomer Zhang Heng built the world's first seismoscope, a bronze vessel with eight dragons. When the ground shook, a ball dropped from one dragon's mouth into a toad's, showing the direction. According to the chronicle, in 138 it registered an earthquake in Longxi, some 500 km away, that no one in the capital had felt.
Wikipedia (Russian) · Wikipedia (English) · 2nd century
Meanwhile around the world (±25 years)
Africa
- c. 150 Ptolemy's Almagest — 18 years later
Alive at the time
- Marcus Aurelius (aged 11)
- Claudius Ptolemy (aged 32)
- Galen (aged 3)
- Zhang Heng (aged 54)