First seismometer Hou feng di dong Yi Chinese first seismometer build with a wine bottle shape with 8 dragons & toads, pretty ancient Chinese style product. Those dragons and toads represent Chinese 'Yin' and 'Yang' ( same as Taichi logo), when 'Yin' 'Yang' occur together, it normally represents the balance between black and white, as old Chinese people consider the earthquake cause because the unbalance under the ground; also the is an old story about earthquakes says: before the earthquake comes, toads will show up, therefore toad becomes a symbol of earthquake. So here we can see ancient Chinese people like to use animals to represent things or tell stories, also we can tell this from Chinese people use 12 animals to symbolise different years. This can be easily remember than those written words and makes the story or things looks or hears more interesting, therefore increasing those stories lives.