候風地動儀 [ㄏㄡˋ ㄈㄥ ㄉㄧˋ ㄉㄨㄥˋ ㄧˊ; hou4 feng1 di4 dong4 yi2] the world's first seismograph invented by Zhang Heng 张衡 in 132 ◄ ►