What is the development process of time-lapse method?
In the Han Dynasty, it was changed to 120, and in Nanliang it was changed to 96 and 108. The opportunity of missing engraving was repeated several times, and it was not until the introduction of European astronomical knowledge in the late Ming Dynasty that the reform of 96 engraving was put forward and made it a formal system in the early Qing Dynasty.
Yan Su, a scientist in the Northern Song Dynasty, made great achievements in his life. People call him a "clever thinker". The lotus leak he made was used in many States at that time.
Yan Su is proficient in astronomical calendars. He deeply felt that the instrument for calculating time at that time was not accurate enough, complicated in structure and inconvenient to use. The urgent task is to make new prints, so he decided to invent a new timer. After repeated research, he finally made a new timing tool-lotus lettering.
Lotus carving leakage has been greatly improved compared with the old model. It is filled with water from the upper and lower pools, the upper pool leaks into the lower pool, and then the copper birds are evenly injected into the stone pot. There is a lotus leaf cover on the stone pot, and a floating arrow engraved with lotus flowers is inserted in the center of the lotus leaf cover.
This arrow is made of wood. Because of the buoyancy of water, it can pass through the lotus plumule and rise along the diameter. There is a scale on the arrow, from which you can see what time and solar terms are.
According to the subtle differences in the length of day and night in a year, the 24 solar terms are made into 48 floating arrows with different scales, and each solar term is replaced day and night. This kind of notch is simple to make, accurate in timing, exquisite in design and easy to popularize.
After the test, Song Renzong released it for national use in document 1036.
After the release of Lotus, it was well received by all parties. North Korean official Xia Song called it "every minute is not bad", and all over the country "erected stones to reflect its laws", and Su Shi, a famous great writer, also praised it greatly.
Wherever seriousness goes, it introduces and disseminates the production method of lotus leakage in the form of inscriptions, and makes samples to promote it. This enthusiasm for spreading science and technology is admirable.
In fact, before this, China has been using the leak timer for a long time, which can be said to have a long history. What we usually call "moment" is used to express time, which involves the cultural historical facts of China ancient dripping timing.
Before mechanical clocks and watches were introduced to China, nicking was the most commonly used timer in China. Simply put, the principle of water leakage timing is to slowly leak water through a small hole and calculate the time by using the rise and fall of water level in the container.
Leaking is an ancient timer in China. "Leakage" refers to the broken kettle wine used for timing, and "engraving" refers to the time measurement unit that divides a day. Leaky cauldron timekeeping day and night 100 lettering. It is in this cultural fact that "printmaking" has the function of expressing time.
Leak carving originated very early in China. There was a book in the Southern and Northern Dynasties called "The Missed Engraving Classic", which said that the missed engraving originated in the era of the Yellow Emperor and developed greatly in the Xia and Shang Dynasties. Tian Wenzhi of Sui Shu also thinks that the leaky carving was invented by the Yellow Emperor who observed the water leakage in the container and was inspired by it.
As early as the Neolithic Age, people have been able to make pottery, and residual leakage will inevitably appear in the use of pottery, leading to water loss. It is instructive that the loss of water takes time. The change of water consumption indicates the passage of time, which gradually leads to the occurrence of engraving leakage.
After entering the Zhou Dynasty, the status of the leaky pot was further improved, and there was an official in charge of the timing of the leaky pot in the court, called "Chuo Hu". Since then, there have been institutions and personnel specializing in the management of missing engravings, and the system has become more and more perfect.
It is speculated that the hundred-engraving system used in the timing of missing engravings in the past dynasties was first formulated by the Shang Dynasty, so the ancients sometimes called "engraving" "Shang", which is a strong evidence of the development of missing engravings in the Shang Dynasty.
The original leaky pot is single, a small mouth is opened at the bottom of the pot, a wooden pole engraved with scales is put in the pot, and the time can be known when the water level retreats to which scale. Because the early use of clepsydra was mostly related to the military, this kind of wooden pole was called "arrow pole", and this method was called "diving arrow method".
Another method is to insert the arrow into the arrow boat, and the shaft of the arrow is engraved with a timeline. When the pot is full of water, the arrow shaft rises very high by the buoyancy of the wood block. With the loss of water, the arrow boat sinks and the shaft falls. By observing the tick marks, you can read what time it is. This method is also called "sinking an arrow".
The timing accuracy of the leaky cauldron is slightly higher than that of the leaky cauldron, but it is not accurate enough. The reason is that the flow rate of water is related to the water level in the kettle. When the water level is high, the water flow will be faster. With the outflow of water, the water level in the pot will gradually decrease and the water flow speed will slow down, so the falling speed of the wooden arrow is uneven, that is, the timing accuracy of the leaky pot will be lower and lower during use.
In order to improve the timing accuracy of clepsydra, clever ancients discovered a new timing method-floating arrow method.
The earliest floating arrow kettle was a single stage, consisting of two kettles, one was a water supply kettle; The other is just a kettle with an arrow ruler in it, which is usually called an arrow kettle.
Because the water in the pot is constantly injected into the arrow pot, and the time mark on the wooden arrow is constantly exposed from the pot, people can know the time at that time. This is the single-stage floating arrow pot.
The single-stage floating arrow has only one leaky kettle. Because there is a certain time interval for manually adding water to the water supply kettle, the water level changes before and after adding water, resulting in unstable water flow to the arrow kettle, so the timing error is relatively large.
To solve this problem, the time scale on the wooden arrow can be made uneven, but it needs to be checked by other high-precision timing instruments, which was not easy at that time.
Another method is to continuously add water to the water supply and drainage kettle to keep its water level at a certain height, so as to reduce the change of its drainage speed.
After years of practice, people added a compensation pot between the drain kettle and the receiver kettle, so that the compensation pot can supply water to the receiver kettle, and at the same time, it can be continuously supplemented by the water flowing out of the drain kettle, thus keeping the water level of the compensation pot relatively stable. This is a secondary compensation for floating arrows and leaking pots.
Zhang Heng, a famous scientist in the Eastern Han Dynasty, once described the use of the secondary clepsydra at that time:
The clepsydra is made of copper, and there are two clepsydra, which are opened at the bottom. Water from the first leaky kettle flows into the second leaky kettle and is then discharged to the receiving kettle.
Because the length of day and night is different, there are also two sets of receiving kettles, which are used separately during the day and at night.
Therefore, the secondary clepsydra was invented in the Eastern Han Dynasty at the latest.
Two-stage leaky pots can greatly improve the timing accuracy of leaky carving, so three leaky pots are used together.
In an article, Sun Chuo, a famous scholar in Jin Dynasty, recorded the existence of three-level clepsydra for the first time: "If the cylinder is three-level, small drops of water will become an ocean, full and empty." The so-called "three-stage" refers to the use of three circular drainage kettles together.
In the Tang Dynasty, the famous scholar Lu Cai increased the number of clepsydra to four, and thus four clepsydra were born. The Six Classics Map written by Yang Jia, a scholar in the Song Dynasty, also recorded Lv Cai's clepsydra.
In order to improve the measurement accuracy, the ancients not only increased the number of leaky pots, but also made an important improvement, that is, the invention of kettles.
The first person to use the kettle was the Song Dynasty scientist mentioned above. The appearance of this kind of kettle fundamentally solved the problem of water surface stability of leaky kettle.
In ancient China, there were some timing tools similar to the principle of missing carving structure, such as mercury, sand and semi-machinery.
Zhan Xiyuan at the end of Yuan Dynasty and the beginning of Ming Dynasty made a five-wheel hourglass clock, also called "wheel clock".
Although the five-wheel hourglass clock has the word "hourglass" in its name, it does not measure time by the amount of quicksand, but drives the gear system to work with sand as the power. This is a real mechanical clock.
The working principle of the five-wheel hourglass clock is that quicksand flows from the funnel-shaped sand pool to the sand bucket next to the main wheel to drive the main wheel, thus driving the mechanical gears at all levels to rotate. The last gear drives the middle wheel to rotate on a horizontal plane. There is a pointer on the shaft of the middle wheel, and the pointer rotates on the dashboard engraved with lines to show the time.
Zhan Xiyuan skillfully added a set of mechanical transmission device to the middle wheel, so that the two Xiao Mu figures on the five-wheel hourglass turned out once an hour to beat the drums and tell the time.
The five-wheel hourglass clock replaces water with sand, which overcomes the shortcoming that water is easy to freeze in winter and can be free from geographical restrictions. Its first wheel, second wheel, third wheel, fourth wheel and pinion gear train can overcome the shortcoming of too fast sand speed.
It's a pity that Zhan Xi was born at an inopportune time. Such an advanced timer came out only a few years ago, but it could not be popularized because of the political turmoil at the turn of the Yuan and Ming Dynasties.
The five-wheel hourglass clock is the representative of the early mechanical clock in China without the aid of astronomical instruments.
Both the Lotus Leak in Yan Su, Zhan Xiyuan's five-wheel hourglass clock, and the invention of some other timing tools are major innovations in the history of the development of leaky timing in China. However, the timekeeping device, which has been used for the longest time and has the widest application range in Chinese history, is still missing.
The copper pot dripping water, now displayed in the Jiaotai Hall of the Palace Museum in Beijing, was made in 1745 and is still a well-preserved leaky pot in China.
The leaking copper pots are all made of pure copper. Each leaking small tube is carved into the shape of a faucet, and the water flows out of Longkou. The leaky pot at the top is placed on the upper floor of the pavilion building, and there are stairs next to it to go up and down. This pavilion-like building has the same structure as the palace. The workmanship is extremely fine, and the surface of the flat pot is engraved with the imperial inscription of Emperor Qianlong.
The appearance of hints enables people to know the time at any time without frequent observation of astronomy. It reduces the dependence of ancient China timekeeping on natural conditions, which is a great progress in exploring the way of time measurement.