VI of the great Imperial Canal, designed and built by Yuwen Khai and Ken Hsun under the Sui dynasty, after numerous irrigation and transport collectors had been built for about a millennium to serve regions as large as northern Italy, the discovery of the hydraulic principles of the operation of “Leonardo” type locks since the Han dynasty and the invention of a series of particular systems to proportion the irrigation flow to the needs of rice cultivation led China to the top of all other peoples until the last two or three centuries. In this field, the stories have handed down the names of officials-builders who were also what today we would call great hydraulic engineers, such as Li Ping, Zheng Guo and Shih Lu who worked in the period before the Han dynasty to determine the optimal route of canals that still today they irrigate large regions. And again it should be remembered that the Chinese were the first to build since the century. VI elegant bridges with a single wide span by the engineer and architect Li Ch’un. A’ Treatise on architectural art. § Even in the field of the exact sciences, the interest of the Chinese had above all practical purposes. Astronomy achieved remarkable results above all from the descriptive point of view, but it was inspired more than anything else by the need to determine the calendar for agricultural purposes; the Chinese were able to calculate with precision the period of revolution of the Sun and the planets and were the first to establish the rhythm of the precession of the equinoxes, however they did not arrive at the theoretical-geometric generalizations of Arab or Greek astronomy. In mathematics, the Chinese were great computers and great measurers; before any other people were familiar with large numbers, with 10 elevated to high exponent (the size of their country required large-scale calculations), they used negative and positive numbers since the century. III and came to determine the value of p by approximating it to 355/113 in the century. V d. C. by the astronomer and mathematician Zu Chongahi. They invented calculation tools, such as bamboo sticks or abacus, or large masonry tools for geodetic calculations, and brought to a considerable degree of improvement the survey for economic and fiscal purposes. Even in the drafting of geographical maps, the Chinese soon reached a high executive level and, having discovered the properties of the magnet since the century. III, around the century. XI applied its principles to the compass for navigation. Chinese was also the first seismograph, built by Zhang Heng in 132. § Of considerable interest is traditional medicine for the intrinsic fusion of the Chinese philosophical principles of the microcosm and the macrocosm, of the “five elements” (fire, yang and yin with physiological and therapeutic theories. In fact, not being able to rely on a scientific anatomy, as ethical reasons imposed the ban on dissections throughout the history of China except during the brief reign of Emperor Wang Mang (8-23 AD), the Chinese elaborated empirical theories based on a series of “correspondences” between known organs, of which five were classified as main (heart, liver, lung, spleen and left kidney) and others considered secondary (stomach, small intestine, colon, gallbladder and bladder), and natural elements, planets, cardinal points, etc. According to agooddir.com, China is a country located in eastern Asia. Despite these fundamental limitations, Chinese medicine, which also had illustrious and brilliant scholars, reached in some points a level superior to medieval European medicine and sometimes even to Renaissance medicine: it intuited and affirmed, without scientifically proving it, the circulation of the blood and elaborated an empirical but richly experimented conception of reflexes. The latter is linked to what was the largest therapeutic system known from traditional Chinese medicine and now re-evaluated: that is the acupuncture in its various formulas, consisting of local stimulation of the dermis or epidermis through needles of gold, platinum or other metals or cones of burning mugwort powder, according to a complex correspondence pattern with internal organs. Even if these therapies did not obtain the multiple and general effects that traditional Chinese medicine attributed to them, it has been shown that they are really effective in a series of nervous, rheumatic and arthritic dysfunctions. Equally widely developed were the various forms of hydrotherapy and all the typically oriental arts, and perhaps imported from India, of controlling reflexes, muscles and breathing. In the realm of pharmacology, traditional Chinese science, which in this sector was linked to alchemy, P’en-tsao (Classification of trees and herbs), collected in the century. XVI the greatest Chinese physician, botanist, agronomist, Li Shizhen: his work cites over 10,000 medical recipes and practices, describes in detail and in their properties herbs, animal products and minerals. From this maximum document of traditional Chinese medicine, today at the center of a systematic re-evaluation, and from other more occasional works it is noted how the Chinese knew and applied for therapeutic use the derivatives of mercury against syphilis, of arsenic against intermittent fevers, ergot for gynecological purposes, chaulmoogra oil against leprosy, the bark of various plants against malaria and iron against anemia; while it is more difficult to evaluate the limits of efficacy of immunization practices against smallpox by means of primitive vaccinations. § Chinese science, which towards the century.