Ancient technology - mysterious ancient earthquake detector#archaeologicaldiscoveries #ancientstructure #recentdiscoveries Modern seismographs are extremely sensitive pieces of equipment. By recording the slightest movements of laser light or magnets, these devices can detect the smallest of rumbles even when we can't sense them. Many don't realize that the process began nearly 2000 years ago, with the invention of the first seismoscope. In 132 AD, Chinese astronomer Zhang Heng created a seismometer, a device that detects the ground’s movement during an earthquake. It couldn’t predict quakes but it did show what direction they were coming from, even when they were hundreds of miles away. Zhang was also a mathematician and mechanical engineer who constructed many practical devices, including a cart for measuring the Chinese mile, and an early armillary sphere, or globe-shaped model of the heavens. His seismometer, the first known instrument built to detect earthquakes, was important, because devastating quakes happened in many remote regions of China. Zhang's seismoscope was a giant bronze vessel, resembling a samovar almost 6 feet in diameter. Eight dragons snaked face-down along the outside of the barrel, marking the primary compass directions. In each dragon's mouth was a small bronze ball. Below the dragons mouths were eight copper toads with their mouths upraised. The exact mechanism that caused a ball to drop in the event of an earthquake is still unknown. One theory is that a thin stick was set loosely down the center of the barrel. An earthquake would cause the stick to topple over in the direction of the seismic shock, triggering one of the dragons to open its mouth and release the bronze ball. The sound of the ball striking one of the eight toads would alert observers to the earthquake and would give a rough indication of the earthquake's direction of origin. Zhang’s seismometer was lost to history, but replicas exist, including one in the Museum of Chinese History in Beijing and another in an exhibit at the Chabot Space and Science Center in Oakland, California.