What is Time? Other Simple Clocks

Human ingenuity is evidenced by the many different methods used to measure time, before the development of springs and pendulums.

(This is the fourth post of Time and Clocks, the thread that follows Time and Calendars.)

In the Dark Ages of Western Europe, many of the monasteries isolated from the scholarship and learning of the Arabian Peninsula and the Asia practised some very basic methods of timekeeping. Some monasteries used what amounts to ‘monk time’. During the night, where no sundial would work or waterclock could be seen within the abbey or cloisters, a monk would read a set number of pages from the Bible then run to the belfry to ring the bell.

Simple Wastage Devices

A number of wastage devices were also employed: Alfred the Great, while he was hiding from his tormentors, promised that if he regained the throne he would spend one-third of every day in prayer. Once in power he used two candles, 30 cm (12 in) tall, which burned for four hours. He arranged for the horn of boars and deer to be honed down to a transparent thickness so that the candles be protected by the equivalent of a modern lampshade. In this way the candles could be used in any weather.

(Left to right) A candle clock illustration of Al-Jazari’s invention; a typical Medieval style English candle clock; A clock from the Clock Museum in Zacatlán, Puebla, Mexico.

Al Jazari’s candle clock is one of many astonishing technological creations from his Kitab fi ma`arifat al-hiyal al-handisaya (The book of knowledge of ingenious mechanical devices), from the 1200s CE. He was a chief engineer during Zengid dynasty of Mosul and later of Ayyubid general Saladin.

In China, from roughly 500 CE, incense clocks were used, in which a small box containing incense was lit: the lighted incense burned through a maze in the upper part of the box until the end of the day. Other versions include the meaasured burning of incense sticks.

Incense or fire clocks in China used burning lines of powdered incense to measure lapsed time. They were often a decorative focal point in the courts of wealthy officials.

Hour Glasses

Hans Holbein woodcut c.1526 CE and an engraving from the Netherlands. MORS LOQVITVR (Death Speaks for itself), printed by Ludwig König in the early 1600s

Although they seem to have been a relatively late development, it is likely that a version of the hour glass was used by Roman soldiers timing their night watches. Contrary to their name, they have been used for measuring anything from a minute to several hours. They underwent a flowering of interest in the era of the English Queen Elizabeth I, when they were often used in debates and for jousts, and by seafarers on their trips to discover the extremities of the known world. They are still used frequently today for the essential task of timing boiling eggs.

In the next article on we take a look at mechanical clocks…