The standards of weights and measures formulated in the pre-Qin and Qin and Han dynasties applied the achievements of mathematics and physics at that time. The Manual Technology Collection-Examination of Gong Ji, written in the Warring States Period, describes the technical requirements of the standard measuring instruments of Qi State, including the technical requirements of bronze alloy smelting and casting, the specifications, sizes, capacities and weights of three measuring instruments, and skillfully concentrates three measuring units on one standard instrument. At that time, it could not be accurately set by calculation or measurement? A little expression? The inner diameter and the area of the bottom circle of the snow pot, therefore, the size of the inner diameter and the area of the bottom circle of the pot is set by "measuring inside and outside", that is, the size of the circle of the pot is inscribed with a square. Eighteen years in Qin Xiaogong? The cave in 344 BC? The copper square liter issued by Xue and Shang Yang adopts the method of "determining the volume by the degree", that is, determining the volume by the size. Fangsheng is engraved with a volume of 16 1/5 cubic inches, which is the capacity of one liter. Now the measured volume is larger than the original design 1%. Liu Xin, a philologist in the Western Han Dynasty, and Ji Shu and Huang Zhong established a mutual inspection method and formulated three standards of weights and measures. He set the length of the yellow clock rhythm tube as nine inches, and the volume as 8 10 cubic minutes, so he called it a clock. What is the legal reason for being in charge of millet? One millet weighs half two, and two millet? Point off? Corn weighs one or two. Based on the length of 23. 1 cm, the length of the yellow bell rhythmic tube is 20.79 cm, and the volume of a clock is 10 cubic cm. Weigh yourself? 7.4 ~ 7? 酄 69? Wopeng. Count two? Closed hole? The volume of snow is 20 cubic centimeters. What is the weight? Is the point one or two? Snow, right? Point 14.8 ~ 15.375? Xue Ke, how much does a catty of millet weigh? 237 ~ 246? Wopeng Based on the closed tube audio formula, it is found that the frequency of the yellow bell tube is 384 times per second, which is consistent with the neutral tone. The first year of the new dynasty? In 9 AD? Xue's copper measuring instrument is designed and manufactured according to the above principles of Liu Xin. The device is a straight cylinder with ears on both sides. In production, it is necessary to form a structure with five abilities of opening, closing, lifting, fighting and welcoming, and to meet the requirements of one foot deep and two feet heavy. 60 Jin? The specification requirements of snow make the three unit standards of weights and measures combined on the same object, and the manufacturing process is quite complicated. There are 8 1 inscriptions on the front of the container wall, and each container has a minute inscription indicating its size and volume. Mathematicians and legalists of all ages used it as a standard to test the unit value of weights and measures in Qin and Han Dynasties. After vicissitudes of life, this instrument is now well preserved in the National Palace Museum in Taipei. /kloc-in the winter of 0/924, Puyi moved out of the Forbidden City, and the National Government's "Cleaning Committee" found all the cultural relics and property in the palace. 1928, scholar Liu Fu made an accurate calculation of Jia Liang, and found that the scale was 23.09 cm, one liter was 200.6 ml, and one kilogram was 226.7 g, and the pi adopted was 3. 1547. In recent years, researchers have also measured standard instruments such as copper poles, copper balance poles, copper ring weights and copper square buckets in Xin Mang, and the conclusions that Xin Mang 1 23. 1 cm and 1 200 ml per liter are accurate. The weighing unit is between 223 grams and 250 grams per catty, with an average of about 237 grams per catty, which is quite different. The reasons are as follows: First, taking the bulk density of millet as the weighing standard, the unit bulk density varies greatly due to the variety, maturity and dry humidity of millet; Second, there are quite a number of complete sets of standards for weights and measures promulgated in Xin Mang, and several bronze products have appeared in Xin Mang in history. The manufacturing process is very complicated. Compared with the length and capacity, the standard unit value of weighing is not easy to control accurately. Now refer to the notes in Records of Food in the History of Han Dynasty that "gold is a square inch, but it weighs a catty" and the Book of Rites in the History of Han Dynasty that "water is heavy, and a liter of water weighs thirteen taels in winter". What was the weight of a catty in Xin Mang and the Eastern Han Dynasty? 237 ~ 246? There is evidence to prove the relationship between the two. This proves that Liu Xin's creation of establishing the parameter relationship among the three quantities of weights and measures by using the audio principle and the bulk density characteristics of millet is in line with the scientific principle.

After the Han Dynasty, to the Tang, Song and Yuan Dynasties, Liu Xin's standard method was used to test and proofread the small unit measurement system. At the beginning of the Northern Song Dynasty, Li Zhao, a legalist, once made a water scale. One liter of water weighed one catty. It is not practical because it is too different from the prevailing weight standard at that time. In the late Ming and early Qing dynasties, a cubic inch of brass was used as the weight standard. During the late Qing Dynasty and the Republic of China, one cubic decimeter of water was used as the weight standard. The capacity standards of Tang, Song, Yuan, Ming and Qing dynasties were all formulated and promulgated by official standards. Therefore, although the units of measurement in ancient China for more than 2,000 years increased sharply for a period of time, they have been greatly reduced since the Tang Dynasty. But on the whole, the unit values of weights and measures in China have a standard transmission track to follow.