Science and technology of the Tang dynasty
As a result of the much wider distribution and circulation of reading materials, the general populace were for the first time able to purchase affordable copies of texts, which correspondingly led to greater literacy.
[5] A copy of the Diamond Sutra found at Dunhuang is the earliest surviving full-length book printed at regular size, complete with illustrations embedded within the text and dated precisely to 868.
[24] Yi Xing's astronomical clock and water-powered armillary sphere became well known throughout the country, since students attempting to pass the imperial examinations by 730 had to write an essay on the device as an exam requirement.
The two engineers provided a steelyard balance that allowed seasonal adjustment in the pressure head of the compensating tank and could then control the rate of flow for different lengths of day and night.
This included a 0.91 m (3 ft) tall mechanical wine server of the early eighth century that was in the shape of an artificial mountain, carved out of iron and rested on a lacquered-wooden tortoise frame.
[27] Furthermore, as the historian Charles Benn describes it: Midway up the southern side of the mountain was a dragon...the beast opened its mouth and spit brew into a goblet seated on a large [iron] lotus leaf beneath.
If he was slow in draining the cup and returning it to the leaf, the door of a pavilion at the top of the mountain opened and a mechanical wine server, dressed in a cap and gown, emerged with a wooden bat in his hand.
[29] There was also an automatic wine-server known in the ancient Greco-Roman world, a design of Heron of Alexandria that employed an urn with an inner valve and a lever device similar to the one described above.
There are many stories of automatons used in the Tang, including general Yang Wulian's wooden statue of a monk who stretched his hands out to collect contributions; when the amount of coins reached a certain weight, the mechanical figure moved his arms to deposit them in a satchel.
[31] Other devices included one by Wang Ju, whose "wooden otter" could allegedly catch fish; Needham suspects a spring trap of some kind was employed here.
In 657, Emperor Gaozong of Tang (r. 649–683) commissioned the literary project of publishing an official materia medica, complete with text and illustrated drawings for 833 different medicinal substances taken from different stones, minerals, metals, plants, herbs, animals, vegetables, fruits, and cereal crops.
[32] In addition to compiling pharmacopeias, the Tang fostered learning in medicine by upholding imperial medical colleges, state examinations for doctors, and publishing forensic manuals for physicians.
[44][45] Ever since the Han dynasty (202 BC – 220 AD), the Chinese had drilled deep boreholes to transport natural gas from bamboo pipelines to stoves where cast iron evaporation pans boiled brine to extract salt.
[46] During the Tang dynasty, a gazetteer of Sichuan province stated that at one of these 182 m (600 ft) 'fire wells', men collected natural gas into portable bamboo tubes which could be carried around for dozens of km (mi) and still produce a flame.
[48] In 747, Emperor Xuanzong had a "Cool Hall" built in the imperial palace, which the Tang Yulin (唐語林) describes as having water-powered fan wheels for air conditioning as well as rising jet streams of water from fountains.
