In mythology, Horus was considered to be the ancient Egyptian god of the sun. Represented as having the head of a hawk, Horus was son of Osiris and Isis, the supreme Egyptian deities. Our English words for "hour," "year," "horoscope," and "horology" were were derived from Horus’ name. In layman’s terms, horology means “study of the hours”—which includes study of ways of measuring time, of making timepieces, as well as broad consideration of clocks, watches and other timekeeping devices (sundials, hour glasses, graduated incense sticks, time cords, dragon boat alarms, water and oil ‘clocks,’ etc.).

People have measured time in numerous ways throughout the ages. Probably the earliest time-measuring technique was to estimate the sun’s progress across the sky. This led to close observation of shadows of fixed objects—a stick in the ground, perhaps—or even how the shadow of a man’s horse lengthened as the sun rose, traversed the sky and set. Not a superb method of reckoning due to problems like cloudy days, nights (when there are few, if any, shadows), and changing lengths and directions of shadows due to the inclination of the turning earth. Birds are said to recognize seasonal changes because of angles of the sun’s rays and length of shadows. Similarly, people (as intuitive students of light and shadow) often innately compute the passage of time.

Astronomers and military commanders led the crusade for developing increasingly accurate timekeepers. Alexander the Great was said to have had candles made that burned all day (twelve hours). On delivery to him, each was scored in twelve equal divisions so, day or night, he could count passing time intervals. Those pleasure-seeking Babylonians are credited with the “base-12” notion defining 60 second minutes and 60 minute hours that we accept today (1).

It seems natural that measuring time by shadows led to development and use of sundials. The pointer on a sundial is called a gnomon. Our word “know” comes from the same Greek root as “gnomon." The sundial’s gnomon helps it (and us) “know” the time.

For collectors interested in unique timepieces, there are many exciting types of items to choose from. One such item is an incense seal timepiece. From as early as the ninth century A.D., Asian cultures developed incense seal timepieces, which measured intervals using vessels with grids filled with powdered incense. As lighted incense burned along its prescribed trail, it could simultaneously burn equidistanced broom straws stuck in the incense, thus marking passage of intervals by how many of the original ‘straws’ remained unburned (2). Utensils accompanying an incense seal usually consisted of a template (maze or divided grid), a small shovel, a tamper, and occasionally, a piece of metal shaped to a point that could trace the incense trail. Some examples had copper covers, but most were of one metal, usually pewter or paktong (“white bronze” or “white copper”).

To set the incense seal timer going, one removes the cover and places the template inside the top tier on a bed of sand or fine ash. The maze is covered with powdered incense, tamped into place with the blunt-ended shovel. The second tier can be prepared at the same time, so as to not interrupt timing. When the first tier’s incense has all burned, then it is necessary only to exchange one tier for the other.

The template is removed and stored with utensils in the large lower tier. At the stopped position on the incense grid, to the left (or right) of what would be ‘6’ on a regular clock dial, the incense is lit and the cover put into place. Then, through openings in the cover, one places 12 equidistant bamboo sticks (“broom straws”) into the incense trail below. Having 12 broom straws in place, as the incense burns the straws burn and fall away. After some time elapses and, say, only seven straws remain, by subtraction one can tell that five intervals (hours) have passed.

These unique interval timers—incense seal timepieces-were used extensively in Asia from the 15th into the early 20th century. Numerous shapes were employed—leaf, quarter circle, fan, square, round, lute, octagon, coffin, urn, rectangle, melon, bell, double pi, “Five Auspicious Clouds,” dragon boat, and “arm of Buddha” or ju-i scepter. After President Nixon reopened trade with China in 1972, Mr. Stanley Marcus was one of the first United States merchants who traveled to China to establish trade. Mr. Stanley imported the large ju-i scepter for sale at Neiman-Marcus in Dallas, Texas. Having learned about incense seal timepieces through an American Philosophical Society publication (3), the author and her husband were delighted to find and purchase the “arm of Buddha” and several other incense seals from Neiman-Marcus. Subsequently, Mr. Marcus told the author that he was amazed to learn that folk in Dallas recognized these “Chinese fire clocks.”

It probably was 16th century Buddhist missionaries from China who introduced incense seal timekeeping to Japan. The generic Japanese term for “incense clocks” is kobandokei. Some of the lacquered Japanese boxes used for incense seals were huge—two feet square, or more. The Japanese could measure time accurately by using time plates to shorten or lengthen furrows for the incense according to whether days or nights were longer or shorter. In 1872, the Japanese government replaced the lunar calendar with a solar calendar, specifying that each day would be divided into 24 hours, making incense seals useless. Thousands of old seals were shipped to England and to the U.S. to be sold as curiosities. Today, in Japan and in China some, Buddhist temples offer reproduction incense burners (not necessarily incense seals) in several sizes for sale to tourists.

For more information about horology, visit the following web sites:

The National Association of Watch and Clock Collectors -- http://nawcc.org

Horology -The Index (Clock, Watch, and Time Museums) --http://www.horology.com/horology/

The Horological Foundation -- http://www.antique-horology.org/

References

(1) Lathrop, D. (2001). “What Is Horology?” (2001). .

(2) Bedini, S. (1994). The Trail of Time. (Cambridge: University Press).

(3) Bedini, S. (1963; 1964). The Scent of Time, Vol. 53, Part 5. (Philadelphia: American Philosophical Society).