1231-1316
Engineer And Director Of Waterways

Early Life. Born in Hebei, Guo Shoujing was a precocious child. At the age of fifteen, coming across a diagram of the "Lotus Clepsydra," he was able to understand at first sight the principle of this time-keeping device. In late 1251, when a bridge was washed away and no trace of its foundations could be identified, Guo Shoujing was put in charge of the restoration project. He first examined the area and located the site of the old bridge. He then cleared away the mud that covered its footings and had the structure rebuilt, thus guaranteeing passage once again. Completed in only forty days, the project needed only four hundred laborers.

Water Clock. Sometime around 1260, Guo Shoujing cast a bronze water clock for a local observatory. Completed in 1262, it was subsequently moved to the capital, Beijing. He also built a tower...