Candle clock
The so-called candle clock or hour candle is a clock whose time measurement is based on the burning of material. One makes use of the fact that a candle always burns down at the same speed if it has the same diameter and is made of the same material.
functionality
The candle clock shows the elapsed time relatively through the disappeared material. A scale is almost always used to make it easier to read the time that has passed. This is either set up separately behind / next to the candle or attached directly to the candle. In addition, metal pins with weights or bells can be inserted into the candle. When the candle burns down to the pen, it falls down and makes a loud noise. Thus, the candle does not have to be observed continuously and a certain point in time is not easily overlooked.
The reading accuracy of an hour candle is around 5–10 minutes . The thicker the candle, the more imprecise it can be read, as it burns down more slowly. If there is a draft, it can also affect the burning rate. Temperature differences, on the other hand, have no significant influence on the burning rate.
The candle clock had the advantage over other timepieces of the time that it also worked at night or when the sky was overcast. However, the disadvantage was the cost factor wax and the one-time use.
history
The earliest mention of a candle clock can be found in the vita of King Alfred of England , who used the candle clock in Europe in the 9th century. His chronicler Bishop Asser narrated that he spent exactly 8 hours on public duties, 8 hours on studying, eating and sleeping, and 8 hours on prayer. In order to be able to keep up his structured daily routine, he needed 6 candles a day, each burning for 4 hours, which he kept in a lantern in order to optimize the evenness of the burning.
In the Middle Ages, hour candles were used almost exclusively in monasteries . This fact is due to the fact that monks were the first group of people who, due to the times of prayer, required a more precise time measurement than the division into "day blocks" that was common in society at that time. Beeswax was very expensive, which is one of the reasons why many monasteries excelled in beekeeping .
Manufacturing
After the candle has been made, a " calibration device " is required to determine the time. In the monasteries this was done by praying or singing psalms . A special brother ("significator horarum") was responsible for setting the times in the monastery, he did this by chanting certain psalms. As soon as the first reference candle was lit, one began to pray the time for a set period of time (typically one hour , hence the name "hour candle"). As soon as you were done, you marked the spot on a fresh candle to which the reference candle had burned down. This process was repeated until the candle had burned out. The markings on the candle were then transferred to other candles. It is very likely that stencils were also used to make standardized candles. In a manuscript , dimensions for such a candle are noted on the edge.
The scale was attached either separately or on the candle. The method of applying the lines to the candle is unclear, but it is likely that they were melted into the candle surface using soot , as this method is reliable and free.
See also
swell
- Asser, Bishop of Sherborne: Life of King Alfred. In: The Online Medieval and Classical Library. Accessed: January 30, 2008.
literature
- Thomas Peschel: The time in the Middle Ages and in the medieval monastery. (PDF; 6.2 MB) ZeitZentrum, Grenchen 2006