News have been reported since last Friday that toads were jumping all over the places in Sichuan and even in Shanghai:
Sadly most news media only got some biologists to explain the story from perspective of global temperature change. If they would have linked it to the wisdom of our great grandfathers, people might have been more alert and thus less casualties and dead toll.
According to the History of Later Han Dynasty (25-220 AD), Zhang Heng's seismograph was an urn-like instrument with a central pendulum. An earth tremor would cause the pendulum to loose balance and activate a set of levers inside.
Then, one of the eight dragons placed in eight directions outside the urn would release a bronze ball held in its mouth. The ball would fall into the mouth of a toad and give off a sound in the meantime, letting people know when and in which direction an earthquake had occurred....
译文:
数千只蟾蜍提前4天即上周五，已经预见了5.12地震
上周五有新闻报道四川甚至上海遍地都是蟾蜍：
可悲的是大部分新闻媒体仅仅让生物学家从全球气温变化的角度去解释这一现象。如果他们能够受到伟大祖先的智慧的启发，人们会更警惕，也不至有如此惨重的人员伤亡。
据汉朝晚期史料记载（公元25-220），张衡发明的地动仪形如酒壶，中心设有一个钟摆。地震波会使钟摆失去平衡，并触碰壶内的一个杠杆。
壶外按东，西，南，北，东北，东南，西南，西北八个方位各设置了一条龙。然后，其中一个方向的龙嘴里含着的铜球便会滑落。小球落入蛤蟆的嘴里并发出声响，这样观测人员便知道什么时间什么方向发生了地震。