A Song dynasty official who read ancient climate change in buried bamboo
In eleventh-century China, Shen Kuo came across petrified bamboo buried underground in a dry northern region where no bamboo could grow in his day. He concluded the climate there must once have been different, one of several ideas that make this court official look startlingly modern.
His most famous observation concerns the compass. In his Dream Pool Essays of 1088, Shen gave the first known description of a magnetic needle compass, a century before Alexander Neckam described one in Europe. Experimenting with suspended needles, he noticed they did not point exactly north, recognising magnetic declination and the difference from true north, which made compasses far more reliable for navigation.
The same curiosity ran through the landscape. Marine fossils found far inland, plus what he knew about erosion and silt deposits, led him to argue that land forms slowly over time. He noted the link between a concave mirror's focal point and a pinhole, recorded drydocks for repairing boats and the new canal pound lock, and wrote so fully about Bi Sheng's movable type that much of what is known about that early printing comes through him. He even set down eyewitness accounts of strange flying objects.
Science was a sideline to a demanding career. Born in Qiantang, now Hangzhou, in 1031, he was first taught by his well-educated mother and travelled widely as his father took provincial posts. After three years of mourning his father, he began in minor local jobs, where he designed a drainage scheme that turned about 100,000 acres of swamp into farmland. He passed the imperial examinations in 1063 among the top candidates.
At court he served as an ambassador to the Western Xia and Liao states, a military commander, a finance official and head of the Bureau of Astronomy from 1072. There he improved the armillary sphere and gnomon, invented a new inflow water clock, and with his colleague Wei Pu proposed calendar reforms and a five-year plan of daily observations of the Moon and planets, which political rivals blocked. He sided with Wang Anshi's reformers, and he died in 1095.
Source: Shen Kuo
