How to time the sundial at night?

There were many ancient timekeeping tools, and there were two common ones, one was a sundial and the other was a leak. The sundial is timed according to the movement of the shadow, which corresponds to the scale on the surface of the sundial. A sundial is also an instrument for measuring time by observing the shadow of the sun, which mainly determines the time or the number of minutes at that time according to the position of the shadow. Judging from the unearthed cultural relics, the sundial was used before the Han Dynasty, and it was always a common timer before the mechanical clock was introduced to China. The main part of a sundial consists of hands and facets. When the sun moves in the sky, the projection of the hand moves on the surface like the hands of a clock, which can indicate the time. You should have seen it in the Forbidden City and the Observatory in Beijing. Water leakage is timed by dripping water, which is made up of four copper pots filled with water, which are stacked on top of each other. There are holes in the bottom of the first three, and an arrow-shaped buoy is vertically placed on the bottom one. The water level rises with the drop of water, and the pot body has scale timing. Guibiao is the oldest timepiece in China. There are records about the use of Tugui in the ancient book Zhou Li, which shows that Guibiao has a long history. Standard gauges use the length of the sun's projection to judge time. It consists of two parts, one is the benchmark or stone pillar for measuring the shadow of the sun standing upright on the flat ground, which is called the table; One is a rigid plate used to measure the length of the surface shadow in the direction of due south and due north, which is called Gui. Since the shadow of the sun can be measured in units of length, it is logical to express the "yin" of time and the length of time in minutes and inches. Both the standard watch and the clepsydra use the shadow of the sun to calculate the time, but it will lose its function when it rains or it gets dark, so a kind of water clock that can time day and night is produced, which is the clepsydra. Leakage refers to the leakage of the pot; Carving means carving an arrow. The arrow is a ruler marked with a time scale. Missing carving is to calculate the time by observing the data displayed on the carved arrow in the pot by using the principle of balanced dripping. As a timer, cracks are more common than sundials. In ancient China, many literati and poets left many poetic chapters about missing prints. For example, Li He, a poet in the Tang Dynasty, said, "It's like adding seawater to a palace leak and dropping Nagato overnight." Su Shi in Song Dynasty: "When the moon is absent, people are quiet." Before mechanical clocks and watches were introduced to China, nicking was the most widely used timer in China. It is inconvenient to use the flow of water to time the mechanical timer, and people gradually invented the use of water as power to drive the mechanical structure to time. In 65438 BC+065438 BC+07 BC, Zhang Heng in the Eastern Han Dynasty made a large astronomical timekeeping instrument-the water-borne armillary sphere, which initially possessed the function of a mechanical timer. Subsequently, instruments with timing devices were manufactured in successive dynasties, among which the waterwheel made in Su Song in Song Dynasty pushed the development of mechanical timing devices to a new peak. The timing mechanism part of the waterwheel allows the puppets to come out at any time to beat the drums, ring the bell to tell the time, and display the signs at twelve o'clock, ugly, cloudy and hairy. This kind of timer is not an independent timer, but also a mixture of astronomical instruments and timing instruments. By the 1960s, China's mechanical timepieces had been separated from astronomical instruments, including not only the transmission system-gear system, but also the escapement. If we go further, there may be a completely modern clock. Unfortunately, China failed to do this, and eventually imported mechanical clocks from the West. Besides the master timer mentioned above, there are other timing methods. Such as incense seals, sand clocks, oil lamp clocks, candle clocks, etc. The original day and night was divided into 100 minutes, which was changed to 96, 108 and 120 minutes successively because it was not divisible with twelve o'clock, and it was officially set as 96 minutes in Qing Dynasty. In this way, one hour is equal to eight quarters. A moment is divided into three points, and a day and night has twenty-four points, as opposed to twenty-four solar terms. Note that this minute is not the current minute, but a word. Between two moments, two strange symbols are engraved, so it is called "word". The word is divided by lines as thin as wheat awn, which is called "two"; The word "two" consists of "he" and "Shao", where he refers to wheat and Shao refers to tiny awns. You can't row below seconds, you can only say "as thin as spider silk", which is called "suddenly"; For example, the word "suddenly" suddenly refers to a very short time, but it refers to change, which means change in a very short time. Now the daily day and night is 24 hours, while in ancient times it was 12 hours. When western mechanical clocks and watches were introduced into China, people called the time points of China and the West "Da Shi" and "Shi Shi" respectively. With the popularity of clocks and watches, people forget "Da Shi", and "Shi" is still in use today. In ancient times, time (big time) was not counted by 1234, but marked by ugly children and animals such as rats, cows, tigers and rabbits, which was easy to remember. The specific division is as follows: from eleven o'clock to one o'clock, twelve o'clock is the punctuality; Ugly (cattle) from one to three, with two points as the punctuality; Yin (tiger) is from three o'clock to five o'clock, with four o'clock as the punctuality; Mao (rabbit) is from five to seven, with six o'clock as the punctuality; Chen (Dragon) is from 7: 00 to 9: 00, with 8: 00 as the punctuality; It's 9 o'clock to 1 1, and 10 is the punctuality; At noon (horse), it is eleven o'clock to one o'clock, with twelve o'clock as the punctuality; When you are not (sheep), it is 1 until 3 o'clock, with 2 o'clock as the punctuality; When applying for (monkey), it is from three o'clock to five o'clock, with four o'clock as the punctuality; You (chicken) are from five to seven, with six o'clock as the punctuality; From 7: 00 to 9: 00, 8: 00 is the punctuality; Shanghai is now 9: 00 to 1 1 point (pig), and 10 is the punctuality. The ancients said that time and day are different, saying "bell" during the day and "more" or "drum" at night. There is also the saying "the morning bell and the evening drum". In ancient times, there were many bell and drum towers in towns. Ring the bell in the morning (7 o'clock today), so say "what time" during the day; At dusk (today 19), drums are ringing, so the night is also called a few drum days. It is more useful to say time at night, because the night watchman beats the banger while patrolling and tells the time by counting. The whole night is divided into five classes, and the third class is midnight, so it is also called "midnight". The unit of measurement below hours is "hours". One hour is divided into eight hours, and each hour is equal to fifteen minutes now. There is a saying in the old novel called "chop at noon three times", that is, chop at noon three times (fifteen minutes away from noon), when the yang is flourishing and the yin disappears instantly. This heinous crime should be "not even allowed to do ghosts" to show severe punishment. The word "Zi" is engraved below. As for Zi, it is still used in Cantonese in Guangdong and Guangxi, such as "3: 10 pm", which means "15: 50". According to the analysis of linguists, there are a lot of "ancient Chinese" in Cantonese. The reason is that the Han people in the ancient Central Plains lived in Lingnan, separated from the Central Plains people for a long time, and their languages did not "keep pace with the times" with those who stayed in the Central Plains. The division under the word "zi" is unknown. According to Sui Shu's law, second is the ancient unit of time, and below second is "sudden"; How to convert, the book did not make it clear, only said: "'two' is as thin as a mountain; "Suddenly" is like the best spider silk. "Qin 12 note time: that is, the twelve earthly branches: Yin, Mao, Chen, Si, Wu, Wei, Shen, You, Xu, Hai, Zi and Ugly. Noon refers to the present eleven o'clock to thirteen o'clock. An hour is divided into eight quarters, starting from eleven o'clock, every fifteen minutes, and starting from noon at eleven o'clock. Yin and Yang experts say that Yang is the most abundant, which is different from modern astronomy. Not at noon, but at three o'clock. In ancient times, beheading was also carried out in different periods, which is why beheading is important. Generally, beheading is to operate at noon and let it have a ghost to do; Repeater or heinous criminals must choose the operation at 3: 30 noon, and don't let it be a ghost. The meridian gate of the imperial city is also the most prosperous, regardless of time, so the emperor ordered the people who started the meridian gate to behead, and no ghosts did it. It's midnight, the rooster crows, the sun rises and the sun sets at noon. It's dusk and the ground is ugly. It's late at noon in Tatsumi, at 23- 1 o'clock, 1-3 o'clock, 3-5 o'clock, 7-9 o'clock and 9- 1 o'clock. 15 o'clock 15- 17- 191212 1-23 o'clock. In modern times, it's five o'clock and five nights./ +0-23 midnight, three drums, three nights, three nights, 23- 1 o'clock, crow, class four, four drums, midnight, 1-3 o'clock, Pingdan, class five, five drums, five nights, 3-5 o'clock, so the ancients often beat drums to report classes at night. In ancient times, time was measured by dripping water, but at night, time was transmitted by lettering. Time is time, please refer to prehistoric chronology. The ancients divided the night into five classes, each with five points. Each point is about 24 minutes in modern times. The ancients divided a day and night into 100 hours, but it was actually 96 hours, and each hour was 15 minutes. Finger leakage time is short.