Incense clock, Chinese, 18th century.

Made by Ming Hsin in the town of Chao, China, this maze incense clock is inscribed in Chinese with the words: 'longevity and double happines'. In the Far East, burning incense was often used as a timekeeper, and Chinese texts refer to periods of time as 'the time it takes to burn an incense stick'. The length of incense sticks was standardised and the perfumes which could be incorporated within them enabled the user to keep time simply by using their sense of smell.