medsbyjohn

Siesmagroph

Zhang Heng, was the inventor of the siesmograph. Zhang Heng's seismograph was an urn-like instrument with a central pendulum. The siesmograph let people know what direction and when a earthquake was coming.

The siesmograph was invented in 132 A.D in china by Zhang Heng. They used the siesmograph to help them know when a hurricane was comeing and when. the siesmograph is not used very much today with all the computers and things like that.

An earth tremor would cause the pendulum to loose balance and activate a set of levers inside. Then, one of the eight dragons placed in eight directions outside the urn would release a bronze ball held in its mouth. The ball would fall into the mouth of a toad and give off a sound in the meantime, letting people know when and in which direction an earthquake had occurred.