Ah, the candle clock. A timeless invention that has been used to measure time – and wake people up – for ages. And it works in such simple but cool way.
Candle clocks, also known as candle timers, are devices that use the rate of burning of a candle to measure a specific amount of time. The most basic form of a candle clock consists of a candle, a holder, and a marking on the candle or holder that indicates the amount of time that has passed.
The principle behind a candle clock is that the rate at which a candle burns is relatively consistent, making it a rather reliable means of measuring time. A candle clock works by burning a candle at a steady rate and marking the candle or holder at specific intervals, such as every half-inch, to indicate the amount of time that has passed.
The earliest known candle clocks date back to ancient China, with the first recorded reference coming from a Chinese poem by You Jiangu written in 520 CE. There, they were used to measure the passage of time during religious ceremonies. The candle was lit at the beginning of the ceremony and allowed to burn until it reached a certain point, at which time the ceremony was over. This was a simple yet effective way to keep track of time.
The candle clock was also used in ancient Egypt, to measure the length of the day. The Egyptians would light a candle at sunrise and then measure the length of time it took for the candle to burn down to a certain point. This allowed them to accurately measure the length of the day.
A famous example of an especially intricate candle clock design is by Al-Jazari – a 12th century Muslim engineer and polymath who created a clock using a system of pulleys and weights to transform the continual burning of the candle into time which could be read on a frontward dial. The inventor also designed water-based clocks which tracked astrological movements.
The candle clock was also used in Europe during the Middle Ages, for example by monks who utilized it to measure the length of their prayers and other religious ceremonies. During the 18th century, the simple design was also used in the American colonies to measure the length of time between sunrise and sunset, allowing farmers to know when to start and end their workday.
This method of telling time remained in use throughout at least the 18th century, despite the increasing availability of traditional wound clocks. Besides indicating the time, candle clocks could also serve as alarm clocks, with the candle serving as an alarm mechanism. The flame would gradually burn down over a set period of time before extinguishing itself and sounding an alarm.
The most simple design – also used in Ancient Rome – involved sticking metal nails into a candle at a desired time interval and place the candle in a metal holder. Once the wax melts down to the desired level, the nail falls into the metal base with a clatter, waking the person up. This was probably the easiest alternative for workers to factory whistles, street criers, and (of course) roosters.
A more intricate design from the 17th century can be seen at Museo Poldi Pezzoli in Milan, Italy. A luxurious and advanced timekeeping device for its time, this candle alarm clock had an alarm mechanism that would sound at a specific time, triggered by a burning candle.
Today, the candle clock is still used in some parts of the world, although it has been largely replaced by more modern methods of timekeeping. But, parallel to this trend, it is also gaining popularity with many people for different reasons.
One of the benefits of using a candle alarm clock is the soothing and calming effect that the flickering flame can have on the user. Many people find the soft glow of a candle to be more relaxing than the harsh light and digital displays of traditional alarm clocks. Additionally, the gradual burning of the candle can serve as a visual representation of the passing of time, helping the user to relax and fall asleep more easily.
Another benefit of candle alarm clocks is their eco-friendly nature. Unlike traditional alarm clocks that require electricity to operate, candle alarm clocks are powered solely by a candle and do not contribute to energy consumption.
And, probably the main reason why the candle clock still holds a special place in the hearts of many is that it stands as a reminder of a simpler time when life was measured by the burning of a candle.