A replica of an ancient time instrument, a Beilou, was unveiled at the Beijing Drum Tower last Saturday.
With a height of 2.2 meters and width of 1.4 meters, the wooden stele-like instrument is equipped with 12 zigzag copper pipes arranged side by side. Once copper balls fell from the upper part of the timer, rolling down and making pleasant sounds upon hitting the copper pipes to record the time.
According to Chen Meidong, a scientist with the China Academy of Sciences, after the first ball is operated, the others will follow automatically under the unique mechanism of the timer. Every ball follows the other every 24 seconds, and thus 36 balls need 14.4 minutes and 3,600 balls would count 24 hours, Chen said.
The ancient timer was said to be invented by a monk in the Tang Dynasty (618-907) and had been widely used in the dynasties of Tang, Song, Jin and Yuan. But the skills required to create one were lost until recently. The Beijing Drum and Bell Tower Artefacts Protection Department and the Suzhou Ancient Timer Research Centre took a year to reproduce the timer.
(China Daily 12/30/2005 page6)