Keeping time with water and cymbals

To the north of the Forbidden City in Beijing there are two towers which used to provide time signals for residents of the capital city.

These are the Drum Tower and the Bell Tower. Every two hours one or other would sound a signal that would drift across the city letting everyone know the time. Naturally, there is a huge bell in the Bell Tower and huge drums in the Drum Tower.

But, the timekeepers needed to know the time themselves in order to start hammering on the giant drums or applying the clapper to the bell. An ingenious bronze water clock, known as a clepsydra, kept track of the time. This used four tanks with water flowing from one to the other. The original machine, from the Song Dynasty (960-1279) has been lost but a replica can be seen today in the Drum Tower. Originally the tower was known as the Qi Zheng, or Administration Unification Tower.

The top tank was known as the Sky Pond, the second as Calm Water, the third as Myriad Parting and the fourth as Water collecting. A little statue of a man, the God of Cymbals, clashed his symbols together eight times every quarter of an hour, triggered by the flow of water. Time could, therefore, be tracked.

The water clock was sophisticated as a wooden ruler protrudes from the bottom tank, supported by two dragons. Nearby is a rack with other rulers, and all are carefully marked with divisions. No doubt, different rulers could be used for different purposes. Being wood they would float upwards with the rise of water in the tank, allowing different time divisions to be marked.

Today visitors make the steep climb up to the drum chamber of the tower and every so often a team comes out and beats the huge drums. But the sound does not carry far across the roar of modern Beijing traffic. Few people do more than glance at the remarkable water clock.

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©Phillip Bruce