The name of the ancient clock

In ancient China, people invented many time-keeping methods or tools. Guiyu is a simple and important astronomical instrument, which consists of a vertical watch (usually eight feet high) and a horizontal Guiyu. It uses direct facts to measure the length of the sun shadow. The main function is to determine the location of the winter solstice, and then determine the length of the tropical year. In addition, we can also determine the direction and solar terms by observing the changes of surface shadows. The sundial (pronounced gu), also known as "sundial", is another kind of timing instrument in ancient China. It usually consists of a copper pointer and a stone disk. The pointer made of copper is called "needle" and the disk made of stone is called "face". When in use, you can distinguish different times by observing the shadow position cast on the disk surface. The sundial can be timed accurately to the minute (15 minutes). The dripping of copper pot is also called "leaky carving" or "leaky pot". That is, the water level of the copper pot is changed by the running water at the bottom of the pot or a water holding tool with a small hole near the bottom of the pot to calculate the time. The copper pot drip invented by China is much earlier than the drip timer made in foreign countries, and it is also widely used, which has become an important tool for timing in past dynasties. In addition to the above-mentioned timing methods, people in ancient China also used "hourglass timing", "fire timing" and "candle timing" to time.