摘要: The medieval interest in mechanical contrivances is well illustrated by the development of the mechanical clock, the oldest of which is driven by weights and controlled by a verge, an oscillating arm engaging with a gear wheel. It dates back to 1386.Clocks driven by springs had appeared by the mid-1 阅读全文
posted @ 2013-02-22 17:01 王文城 阅读(256) 评论(0) 推荐(0)