The crossbow, which once greatly boosted the strength of the invincible Qin troops, first appeared in the Spring and Autumn Period. By the Han Dynasty (206BC-220), the precision and the flatness of the device were noticeable. The Han crossbows were divided into eight categories, demonstrating the manufacturing standardization that was primarily established in China early in the Han Dynasty. The craftsmen's name was engraved on each of the crossbow.
Kao Gong Ji, prevailing in the Warring States Period (475-221BC), was the earliest extant professional treatise on craftsmanship. The book covered a wide range of subjects such as the manufacturing method of wheels, the elasticity of bows, and the velocity and stability of arrows. Various ships, including three- or four-storied ones, abounded in the Han Dynasty, while some were equipped with a stern rudder and an efficient advancing tool - the scull (an oar placed over the boat's rear part to propel the boat). The incense burner in the Western Han Dynasty was skillfully designed. No matter how the ball-shaped burner rolled, the part in the center where the incense was burned could remain horizontal.
Ⅱ. Development of transportation tools and emergence of a complex drive structure
The bronze cart and horses excavated in 1980 in the Qin Shihuang Mausoleum (site of the Terracotta Warriors) of Xi'anin North China's Shaanxi Province represented the development level of casting technology, metal processing, and assembly skills at the time. The Jiligu cart (which had a group of decelerating gear insides) and the compass vehicle appeared after the Eastern Han Dynasty.
The compass vehicle produced by Ma Jun in the Three Kingdoms period (220-280) not only applies a gear-driven system, but also an automatic clutch device, highlighting its improvement over the Jiligu cart. The invention of the automatic clutch device also demonstrates the considerable development of a complex drive structure.
Gears and gear clusters in various shapes and of different uses, highlighted by ratchet wheels (wheels that are toothed in a way that ensures motion in a certain direction) and especially the highly accurate gear cluster used in astronomical apparatuses, abounded in the Eastern Han Dynasty (25-220). The armillary sphere (three-dimensional map of the celestial sphere) and the seismograph invented by the Chinese scientist Zhang Heng in the year 132 best exemplify the achievements in transmission.
The textile technology and weaving machine experienced significant achievements in the Han Dynasty. By the Three Kingdoms period, Ma Jun enhanced the weaving machine, greatly improving working efficiency. Meanwhile, he also invented a kind of waterwheel, which could continuously lift water from a lower place to a higher place.
