基于两京(都)制论证候风地动仪存在的合理性

Textual Evidence for the Existence of the Houfeng Seismograph Based on the Two Capitals System in Ancient China

张衡的候风地动仪是否真实存在,至今还是一个有争议的科学与历史问题。否定其最大的理由在于因历史记载产生的矛盾。依《后汉书·张衡传》记载,张衡于阳嘉元年(公元132年)建造候风地动仪,而其卒于永和四年(公元139年)。在此期间,《后汉书》只记载过一次地震,即永和三年(公元138年)的甘肃陇西地震。一般认为候风地动仪记到的是此次地震。矛盾之处在于对公元138年甘肃陇西地震的历史记载出现不一致的情况:《后汉书·五行志》记载当时京师"裂城廓,室屋坏,压杀人",即在陇西地震的同时,京师也发生了破坏性的地震;而《后汉书·张衡传》却说"尝一龙机发而地不觉动,京师学者咸怪其无征",记载的是在陇西地震发生时京师并无任何有感地震发生。由此,有人认为,在公元138年候风地动仪记录地震的同时京师就已经发生强烈有感地震了。人都有感,地震动仪记到也就不足为奇了。更进一步,由于历史记载出现矛盾,地动仪无出土实物,发明后很快遗失,因而就认为候风地动仪历史上并非真实存在,其存在性值得怀疑。本文针对这个记载矛盾做出另外一个解释,论证在东汉时有两个京师,一是长安,一是洛阳,京师震指的是长安,而候风地动仪放在河南洛阳。从而对历史记载中的矛盾有所解释,一定程度上肯定了候风地动仪存在的真实性。

The actual existence of Zhangheng＇s seismograph is still controversial in science and historical circles,in great part because of contradictions within historical records.According to the History of the Later Han Dynasty：Biography of Zhang Heng,in the first year of Yang Jia（132AD）,Zhangheng made the seismograph and died in the fourth year of Yonghe（139AD）.During this time,there was only one earthquake that occurred in Longxi,Gansu Province,according to the History of the Later Han Dynasty,which occurred in the third year of Yonghe（138AD）.It is generally considered that this event must be the one the seismograph so famously recorded.The paradox lies in an inconsistency between historical records of the 138 AD Longxi earthquake.An accounting of property damage at the capital appears in the History of the Later Han Dynasty：WuXing Zhi,which means at the time of the Longxi earthquake,a destructive earthquake also struck the capital.However,according to the History of the Later Han Dynasty：Biography of Zhang Heng,when the Longxi earthquake occurred,no earthquake was felt at the capital.Therefore,in 138 AD,when the Houfeng seismograph recorded the earthquake,people in the capital should have strongly felt it.It would not be surprising that the seismograph could record the earthquake if people could feel it.Because of the conflict between the historical accounts,and because the seismograph was lost soon after its invention;many people believe that the seismograph did not really exist.This paper proposes another interpretation of the seemingly contradictory records.There were two capitals during the Eastern Han Dynasty：Chang＇an and Luoyang.We know that the seismograph was tested in Luoyang.We propose that the capital that suffered earthquake damage was Chang＇an,which would solve the paradox and serve as a powerful proof that the seismograph existed at that time.