4 0 c m
34cm
actual image size: 26cm x 32cm
Description
Detail. The Chinese astronomer, mathematician and seismologist, Zhang Heng (78-139 AD) described the earliest seismoscope known in about 132 AD. Arriving shock waves displace a pendulum linked to a mechanism which opens the jaws of the dragon facing the direction of the earthquake. A ball falls from the dragon's teeth into the mouth of a toad below to record the event.
Image Details
Image Ref.
10284303
© Science Museum / Science & Society Picture Library