The incense clock (香鐘, 香钟, xiāng zhōng in Chinese) is a timekeeping device invented by the Chinese during the Song Dynasty (960-1279) that spread to neighboring countries such as Japan. Incense sticks or powdered incense that have been manufactered and calibrated to a known rate of combustion is used to measure relatively short periods of time from minutes, hours, to days.

Stick incense clocks

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While calibrated incense sticks can be burned to keep track of time in the same manner as candle clocks, sticks are often used as a part of a more elaborate device. In many 18th- or 19th-century incense clocks, threads with weights or bells on either end were hung over an incense stick at desired intervals. As the incense burns, the threads burned one by one and the weights dropped to a sounding plate, pan, or gong below. Sticks of incense with different scents might be used at different times, so that the hours were marked by a change in fragrance.

Powdered incense clocks

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Another form of incense clock are based on creating lines of powdered incense using incense seals (香印, xiāng yìn in Chinese; kodokei in Japanese).

A fine layer of white wood ash is first laid down in a small container and compacted. Seals that were in the form of patterned metal cutouts were simply laid down on the ash while the incense powder was poured over it. After a light compaction of the incense powder by a tamper, lifting up the metal seal forms a long trail of incense powder that has been masked onto the ash. Other seals have a protruded pattern that creates a negative indentation in the wood ash. The incense powder is carefully spooned into the indentation in the ash and then recompacted again with the seal.

In either case, depending on the size of the seal, the trails of incense may burn for long periods of time from hours to days. Bits of frangrant woods and resins can be placed on the incense powder trails to signal time.

These incense clocks are often made of paktong in the form of multileveled small boxes with patterned porferated tops. Gold and silver powder incense clocks are considered quite rare. Although they are no longer used formally for time keeping, such incense clocks are still used by scholars and monks in East for evoking moods and for aesthetics.

External links

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• Sonao-koh: site shows the preparation and burning of an incense sealed incense similar to the method used for ancient time keeping
• Chinese Enameled Paktong Incense Clock: commercial site showing an example of an incense seal styled incense clock

References

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• Silvio A. Bedini. (1994). "The Trail of Time : Time Measurement with Incense in East Asia". Cambridge University Press. ISBN 0521374820

Clocks | Incense