钟表的变迁早在公元前3500年,人类就开始用日晷来确定时间。由于地球自转和公转的角度问题,用这种方式得到的时间不够准确,大约每天要差15分钟左右。在随后的时间里,人类还采取多种方式来获取较为精确的时间,沙漏、水钟和燃香都曾经被广泛使用。机械钟的出现大大提高了时钟的精 Clock changes as early as 3500 BC, humans began to use sundial to determine the time. Due to the problem of rotation and revolution of the Earth, the time obtained in this way is not accurate enough, about 15 minutes a day or so. In the ensuing time, humans also took a variety of ways to obtain more accurate time, hourglass, water clock and burning incense have been widely used. The emergence of mechanical clock greatly improved the clock fine