In 132 CE,Zhang Heng invented the seismograph

In 132 CE,Chinese polymath Zhang Heng presented the Han court with his latest invention.This large vase, he claimed,could tell them whenever an earthquake occurred in their kingdom–including the direction they should send aid.The court was somewhat skeptical,especially when the device triggered on a seemingly quiet afternoon.But when messengers came for help days later,their doubts turned to gratitude.Today, we no longer rely on pots to identify seismic events,but earthquakes still offer a unique challenge to those trying to track them.