The story of clocks
Primitive man judged time by the color of the sky and the brightness of the sun. The ancient Egyptians discovered that the length of shadows changed with time, and invented sundials to keep time in the morning. They also discovered that water needed a fixed amount of time to flow, so they invented the water clock. The ancient Chinese also had a tool to measure time with water -- a copper kettle dripping.
In addition to using water to measure time, ancient Chinese people also used incense to measure time. Dragon boat timing more incense is the use of incense to the timing of the instrument, it has the role of timing noise.
On the dragon boat hung a number of metal balls at both ends of the fine line, line down the burning incense. Every once in a while, the incense would burn a thread, and when the metal ball fell into the vessel below, it would sound the time. This kind of incense time meter was first seen in the documents of the Song Dynasty.
The accuracy of using more incense to calculate time is not high, but because it is simple and easy to use, very suitable for folk use, so it was very popular. Some have been documented to burn for a day or night, and some for a month.
