地动仪的诞生有着深厚的历史背景,本文旨在探讨张衡科学思想的形成过程和物质基础。张衡生活在东汉文化发展的顶峰时期,"观察异象、辨别凶吉"的朴素愿望是研制地动仪的原始动力。作者追溯了当时的历史背景、张衡的学术历程、地动仪的问世过程,分析了东汉早期的地震活动、古代的地震观念和灵台科学活动的特点。指出地动仪的研制起步于公元128年,张衡基于感性认识升华出两个地震概念——地震的位置可按方位判断、地震和地裂必须加以区别,这使地动仪的研制有了明确的技术追求。仪器制作上,张衡崇尚"制器尚象"的原则。地动仪的测震原理模仿了悬挂物(即天然验震器)对地震的反应,技术实现上借鉴了门闩类的触发机构,还通过龙首吐丸的方式留下了发生地震的物质证据,这3个关键问题的解决成就了公元132年地动仪的问世和134年的成功验震,构成他科技创新的完整内容。地动仪的发明深化了人类对自然规律的认识,对当时的东汉及其后世界文化的发展具有积极意义。

The first seismometer in the world was invented in 132 AD by Zhang Heng in the Eastern Han Dynasty and the birth of this instrument had strongly social and historical background. For Zhang Heng's scientific idea, the present authors would like to discuss its forming process and material basis. Zhang Heng lived in a highly developing period of culture and science in the Eastern Han Dynasty. The original pursue of studying and designing such instrument in ancientness was just a quite simple desire to observe nature anomalies for future prediction. The authors in this paper review briefly the social background at that time, the academic course of Zhang Heng and the historical process of the instrument creation. The paper also analyses the seismic activities in early Eastern Han Dynasty, ancient ideas for earthquake, as well as scientific activities carried in the ancient observatory ( Ling Tai). It appears that corresponding study work of the instrument started in about 128 AD. Based on his experience, Zhang Heng came to two simple and unsophisticated concepts of earthquake, i. e. the quake position could be judged according to its orientation and the earthquake should be distinguished seriously from landslip. Such perceptual knowledge was very significant and made the innovation following clearly after technical requirements. The general principle of Zhang Heng's making is to imitate the objective world as much as possible. The principle of his seismoscope includes the imitated response of hanging object to earthquake, the detecting technique of triggering bolter mechanism, and the recording system realized by dragons spitting a ball. Successful settlements of above three key problems in science and technique made Zhang Heng's innovation completed. The birth of Zhang Heng's seismoscope indicated the first successful use of material inertia by mankind, and had positive social effects in history.

国家自然科学基金项目(40644019);中国地震局科学研究专项“地动仪复原模型的优化和定型设计”