古时候没有钟表,人们根据太阳影子的长短来判断时间。中国古代很早就用日晷计时。河南省登封县告成镇现存元代的一个观星台遗址,台高约9.5米,台下有长约31.2米的南北向的“量天尺”,这是当时最先进的计时建筑。用日影测时受气象限制,很不方便。于是人们发明了漏沙计时的“沙钟”,燃香计时的“火钟”,滴水计时的“水钟”。我国北宋苏颂等人发明了“水运仪象台”,它是最早采用齿轮的机械计时仪,被已故著名史学专家李约瑟誉为“现代天文钟的鼻祖”。 No watch in ancient times, people judge the time according to the length of the sun’s shadow. Ancient China used sundial long time ago. An observatory ruler of the existing Yuan Dynasty in Gaocheng Town, Dengfeng County, Henan Province, with a height of about 9.5 meters and a total of 31.2 meters of north-south “mass days” under the stage, was the most advanced time-laden building of the time. By the Japanese measured by the meteorological restrictions, very inconvenient. So people invented the “sand clock” of the sand-drifting time, the “fire bell” of the chiming time and the “water bell” of the dripping time. Su Song, Northern Song Dynasty, who invented the “water transport device as Taiwan,” which is the first gear mechanical chronograph, was the famous historian Joseph Needham as “the originator of modern astronomical clock.”