The earliest record of the leaked engraving was found in Zhou Li. The most ancient leaks that have been unearthed are the Western Han relics, a total of three, found in Hebei Mancheng, Inner Mongolia Ikezhao League and Shaanxi Xingping. There are two pieces of the more complete pass-through, all of which are water-receiving. The Museum of Chinese History in Beijing was built in the Yuan Dynasty (1316) in the Yuan Dynasty; it was built in the Qing Dynasty by the Palace Museum in Beijing.

 

The influential hourglass records in ancient Chinese history were found in the 1360 Yuan Dynasty, the five-round hourglass created by the great calligrapher Zhan Xiyuan. Zhan Xiyuan believes that it is too simple to just let the quicksand between the two sand buckets count. The five-wheel hourglass he created created a mechanical gear set that uses the power of quicksand to propel the gear set. Such an hourglass has a time dial with a day of engraving, which is equivalent to the clock face of today's clock. There is a pointer in the center of the disc. The pointer is rotated by the axis of the last gear, and the gear rotates to indicate the moment on the dial. . Zhan Xiyuan also skillfully added a set of mechanical transmissions on the middle wheel. These mechanical devices enabled the two small wooden men on the five-wheel hourglass to turn out and drum their time.

 

We can see that the structural principle of Zhan Xiyuan's five-wheel hourglass chronograph is exactly the same as that of modern clocks. However, when Zhan Xiyuan was born, the advanced timer was published for 8 years, and the Yuan Dynasty was destroyed. The emperor of the Ming Dynasty, Zhu Yuanzhang, was also busy with power struggles, and it was impossible to support the development of folk science and technology. This laid the seeds for the later time when our timers lag behind the West.

 

The convenience of the hourglass is that the upper and lower sand buckets can be used upside down. The hourglass also has shortcomings that are difficult to solve. The sandstone is easy to block when it flows. However, in the ancient times, the western sandglass used sand has a secret recipe to solve the problem: they first used the marble powder to cook in the wine nine times and smashed the foam. Use it in the sun and dry it to avoid clogging the hourglass. However, the accuracy of the hourglass timing is worse than the drip leak, so it is as common as the drip leak. In addition, the hourglass must use glass containers to see the amount of sand. China's hourglasses are mostly made of pottery, and it is impossible to see how much sand is stored. This may be one of the reasons why hourglass is not as popular in China as in Western countries.