Candle Clocks: The Alarm Clocks of Antiquity

As a candle lover, I have always been fascinated by their history and their role in people’s daily lives throughout the centuries. It’s not just the beauty of candles that fascinates me, but also the many creative ways people have used them in the past. One such fascinating use is candle clocks, which were the original alarm clocks before electricity. In this post, I’ll share with you a little bit of the history of candle clocks and how they worked.

Before electricity, the candle had many uses. Candles were a critical source of light, could be fixed to chandeliers or carried in convenient brass holders. And their wax could be used to seal correspondence for privacy or official approval. Candles could also be used as alarm clocks—a function that is arguably obsolete now, but is an important part of the history of timekeeping.

The candle clock is an ancient technology. The first recorded reference was in 520 AD in a Chinese poem by You Jiangu. He described six uniform candles of equal weight and thickness, each 12 inches tall. The candles were marked in one-inch sections. Each inch took 20 minutes to burn, and a full candle lasted 4 hours. Enclosed in frames to protect the flame, the candles could be used to measure the passage of time - a technique perfect for when the sun was not visible.

Other early references to candle clocks exist in Japan during the first millennium AD. Thousands of miles away, King Alfred the Great of England was also said to have used this method in English churches.

A candle of any size could be used, as long as the burning time was set and regular. By means of markings, candles could be subdivided for more incremental measurements of the passage of time. This method of measuring time remained in use until at least the 18th century, despite the increasing ubiquity of traditional wind-up clocks.

In addition to telling the time, candles could also serve as alarm clocks. One could place metal nails in a candle at desired time intervals and place the candle in a metal holder. When the wax melted to the desired level, the nail would fall into the metal base with a loud bang, serving as an alarm. This was another option for those looking to wake up early: factory whistles, street cries, and (of course) roosters could also serve this purpose.

A famous example of an especially intricate candle clock is the candle clock of Al-Jazari—a 12th-century Muslim engineer and polymath known for his inventions of water pumps and clocks. He created a candle clock that used a system of pulleys and weights to transform the candle's continuous burning into time that could be read on a dial in front. This advanced system was just one of the inventor's clocks.

Although candle clocks were largely replaced by mechanical clocks by the end of the 18th century, they are still prized today for their beauty and historical value. They are a fascinating reminder of a time before electricity, when people relied on simple technologies to measure time and coordinate their daily lives.

If you love candles and history, candle clocks are a fascinating area to explore. Buy a long candle such as a stick candle and try your hand at creating your own candle clock at home; you’ll surely appreciate the beauty and intricacy of these unique pieces of ancient technology.