Seismograph is a masterpiece handed down from ancient times by Zhang Heng, a scientist in Han Dynasty. According to "Zhang Hengchuan in the Later Han Dynasty", there is a raised dome on the Hou Feng seismograph, and the surface of the instrument is engraved with seal characters and figures such as mountains, turtles, birds and animals. There is a copper "capital column" in the center of the instrument, and there are eight channels beside the column, called "eight channels", as well as exquisite machines and switches. There are eight faucets around the outside of the bottle, which are arranged in eight directions: east, south, west, north, southeast, northeast, southwest and northwest. The faucet is connected with the engine in the internal passage, and there is a copper ball in the mouth of each faucet. Facing the faucet, eight toads squatted on the ground, all with their heads held high and their mouths open, ready to accept copper balls. When an earthquake occurs in a certain place, the bottle moves with it, touching the mechanism, making the faucet in the direction of the earthquake open its mouth, spitting out the copper ball and falling into the mouth of the copper toad, making a loud noise. So people can know the direction of the earthquake. ?
I copied it online. I wonder if I can help you?