Weighing instrument is an important component of measuring instruments. In the past, people called measurement ' weights and measures '. The so-called degree, refers to the ruler (such as ancient bone ruler, tooth ruler and later gradually came out of the bamboo ruler, wooden ruler, tape, steel, etc. measuring the length of an object; the so-called volume, refers to the use of containers (such as ancient Hopewell, liters, buckets, and later used barrels, measuring cups, etc.) to measure the volume of objects;

　　Scale, should start at the end of the primitive society, according to historical records from more than 4,000 years ago, at that time, the exchange of goods, but the measurement method is to see hand touch; In China, the earliest appeared in the Xia Dynasty, the spring and autumn Warring States period has mastered the lever principle, the mid-warring states in the Chu area has been widely used scales and weights weighing gold, but in a very long period of time in the measurement of different standards, more chaotic, until the Qin unified world, in the Qin BC 221), before the unification of the standard of weights and measures, the Song Dynasty has reached the accuracy of 1 pct (40mg) of the arbitrage scale, indicating that the weighing apparatus has a considerable technical level.

　　The inventor of the scale

　　According to legend, Fan Li in business found that people in the market to buy and sell things, is to use the eye assessment heap, it is difficult to do fair trade, it has created a tool to determine the weight of the idea of the goods.

　　One day, fan Li on the way home business, accidentally saw a farmer from the well, the method is extremely ingenious: erect a high stakes in the well, and then tie a piece of wood to the top of the pile, the side of the wooden bucket, the other end of the stone, which is light and labor. Fan Li, inspired, hurried home to imitate it: he used a thin, straight stick, drill a small hole, and fasten the hemp rope on the small hole, use the hand to take down, the fine Wood's one end fastens hangs the plate, uses in holds the cargo, the end fastens a pebble as the mound; The pebbles move farther away from the rope, the more goods can be lifted. So he thought: how much cargo, the other side of the pebbles to move how far to maintain balance, must be engraved on the fine wood to mark the line. But what do you use to mark it? Fan Li pondered for several months, still no matter.

　　One night, fan Li out pee, a rise to see the stars in the sky, then a whim, decided to use Nadou six stars and Big Dipper Mark, a star represents one or two weight, 13 stars represent a kg. Since then, the market has a unified measurement tool-scale.

　　However, a long time, fan Li and found that some evil businessmen, selling things butcher, deduction people. He thought, how to improve the scale, to eliminate unscrupulous businessmen's evil? Finally, he came up with a change white woodcut black star for mahogany inlay metal star, and in the Nadou six stars and the Big Dipper, plus Fu, Lu, shou Samsung, to 72 a kg. The purpose is to admonish peers: As a businessman, must be aboveboard, not to earn black money. and said: "If a businessman deceives a man one or two, he will lose his blessing and happiness, and 22, he will never get the ' salary ' (can't do the official), the person who deceives 32, then can be lost ' due ' (short-lived)!"

　　In this way, the scale of this measurement tool has been handed down from generation to generation, and has been followed for more than 2000 years, until today!