Detailed explanation of "degree"
The name of the unit of length has been around for a long time. In ancient times, it was based on a certain part of the human body or a certain action, such as inch, finger, ruler, Zhang, Xun, Chang and Jie. In these names, ruler is the basic unit of length. The length of a foot is about the same as that of a hand, so it is easy to identify. So in ancient times, there was a saying that "rulers know rulers" and "rulers know". In addition, it is also a practical unit for measuring depth, which constitutes a system alone. The ratio of mowing to feet has never been a definite fixed figure. There are four feet, five feet, six inches, seven feet and eight feet, which is generally considered to be eight feet. The names of length units before the week have been sorted out in Hanshu, including three words: inch, ruler and ruler. There are "points" below the inch position and "quotes" above the ruler position, all of which are decimals, which is the so-called five degrees. Arithmeticians usually use small units of length. The so-called "the length of the degree is not less than one millimeter" only means that the measurement should have the precision of tiny numbers. There is a saying in Sun Tzu's Art of War that "when a silkworm suddenly spins silk, it will be a minute in one second, a minute in ten seconds, a minute in ten, and a minute in ten". These ten abandoned minutes, centimeters and tenths of a second suddenly became arithmetic-specific decimal names and small unit names. In the Song Dynasty, seconds became silk. In the late Qing dynasty, the small unit of length was set at ten.
Detailed explanation of "quantity"
Measuring instruments are the main instruments for measuring the quantity of agricultural products in feudal society, so the measurement of capacity is the earliest and the name of the unit is the most complicated. Classical works such as Zuo Zhuan, Zhou Li, Yi Li and Er Ya all have records about capacity units, and their special names are Sheng, Dou, Hu, Dou, District, Pot, Bell, Overflow and Bucket. Like length, the unit of capacity before the Zhou Dynasty was also measured by the human body. What one hand can hold is called overflow, and what two hands hold together is called "enough", which is the initial basic unit of capacity. Xiao Er Ya said that "four equals beans" and Zuo Gong San said that "four equals beans". These two statements are interlinked, that is to say, "four equals beans". The original meaning of "rising" means "rising" and "entering". Holding the basic ability number in both hands, and then starting from this number, four are beans, areas and kettles, and ten are buckets and welcome guests. So liter (that is, liter) is the basic unit of capacity. Later, Hanshu Faji systematically sorted out the capacity units and named them Hu, He, Sheng, Dou and Hu five quantities. One equals two, and all the following are decimals (after Song Dynasty, one Hu is five buckets). Liter is the basic unit of capacity, while bucket and welcome are practical units. As for the cloud "Ten birds are one" in Shuo Wu, there are different opinions, which can be used for reference. Incidentally, stone was originally a unit of weight, which was 120 Jin, but since the Qin and Han Dynasties, stone has also been used as a unit of capacity, which means welcome. As for the small unit of capacity, the volume of Sun Tzu's Calculations says: "Six millet is one reed, ten reed is one, ten reed is one pinch, ten pinch is one spoon, and ten spoonfuls are one." In this way, six millet is a GUI (once said, ten millet is a GUI), and the remaining eight units of GUI, copy, pinch, spoon and combination, promotion, bucket and welcome are decimals. This calculation method has been used since the Han Dynasty.
Detailed explanation of "balance"
For a long time, baht, taels, gold, jun and stone have been used as units of weight. However, in ancient times, there were different views on the unit of weight. For example, Sun Tzu's Art of War says, "Starting with millet, ten millet is one (the ancient word" tired "), ten millet is one baht, and twenty-four baht is one or two." "Master yuan? Discrimination: "Ten millet weighs one kyu, and ten kyu weighs one baht. "Shuo Wen Jin Wen Bu": "Yi, six baht. "Huai Nan Zi Yan Quan" has a high lure note: "Liu Liang said. "Jade and Gold Department;" Hey, twenty-two years old. "Ji Yun Zhiyun": "Twenty-four beams are enough. "Wait a minute." "Millet", "Millet", "Miao" and "Gui" are all borrowed names from Millet and Guibi, but they are no longer used. "Zi, Yi, Zhong and Yun are all borrowed names of coins, which are no longer used. Therefore, there are various opinions. The names of five units, namely, baht, beam, gold, jun and stone, were consistent until the Tang Dynasty. Its rounding method is worth mentioning: 24 baht is two, 16 is two Jin, 30 Jin is jun, and 4 Jun is stone. Regarding the use of small units such as less than two cents, cents, cents, silk, and suddenly, Liang Tao and Hong Jing of the Southern Dynasties once said: "The name of agency is different today, and there is no difference between ancient times. Today, ten millet is one baht, six baht is one point, and four is one or two. Tang noted: "Six baht is one cent, which is two and a half dollars." It can be seen that since the Tang Dynasty, "money" originally used as money has been regarded as a unit of weight, and "ten money is one or two", but the point carry at that time has not yet been determined as one tenth of money. In addition, there are Li, Li, Mao, Li and Hu. It was originally a decimal name, and later borrowed length as the name of the weight unit. Since the Song Dynasty, they have been designated as decimal units of money. In the Song Dynasty, the names of baht, millet and millet were abandoned, and the names of their weight units in descending order were Shi, Jun, Jin, Liang, Qian, Fen, Li, Hao, Si and Sui, and their carrying methods were as mentioned above. Song system weights and measures have been used until Yuan, Ming and Qing Dynasties, and rarely changed. However, it must be pointed out that in the medical prescriptions of the Song, Yuan, Ming and Qing Dynasties, everything that said "fen" was "fen", while in the Jin and Tang Dynasties, one fen was two and a half pieces, which was different.