Dial
A dial or dial is used in particular in mechanical watches , but also in pointer measuring devices such. B. dial gauges , as an aid when reading values indicated by pointers .
To display the time , the dial is divided into even sections. Usually, the page is divided twelve times to display the hours and 60 times to display the minutes and seconds. To represent the division, indices (in the singular index , colloquially in the plural also indices ) or numbers or digits are placed on the dial , 1 to 12 for the hours, 0 to 60, often in steps of 5 or 10, for the minutes and seconds. The structure of the dial is based on the course of the sun, which it seems to take in the northern hemisphere : When looking south, it rises to the left (in the east), is highest at noon and sets to the right (in the west). This explains the speed course in a clockwise direction and that the 12 at the top. The display of the time or complications on a dial is called an indication .
history
The history of the clock face known today begins with the development of the wheel clock around 1300.
Early dials often only have a division into hours, often interrupted by a division into half or quarter hours. This was due to the accuracy of the clockwork; the first clocks only had an hour hand (so-called one-hand clock ) like the tower clock on Freiburg Cathedral . Early tower clocks like that of Salisbury Cathedral did not have a dial, but a striking mechanism with bells to announce the time acoustically.
It was only after the invention of the pendulum as a rate regulator in the 17th century that the clockworks were precise enough that they could be divided into minutes.
During the French Revolution , dials were classified according to the republican calendar . The day was divided into 10 decimal hours, the hour into 100 minutes, and the minute into 100 seconds. The decimal time was not able to assert itself in the population and was abolished again in 1795, while the calendar was valid until December 31, 1805.
Artistic interpretations such as dials without divisions or without numbers are common. In aviation is used in the pilot's watches for improved readability among other enlarged dials with a 24-hour division and often luminous numbers in Arabic numerals ( Numeralen ) on a black background.
There are hardly any limits to the decoration of the dial. Occasionally one can find inscriptions referring to the passage of time, e.g. B. Vulnerant omnes ultima necat ( Latin ; "All wounded, the last one kills." - meaning hours). Ornate decorations on dials first flourished in the Baroque period.
The most elaborate dials have watches with grand complications and the astrolabes . Techniques such as enamelling , engraving , chasing , skeletonization , guillochéing , painting (also with radioactive material as luminous paint ), varnishing , prints , maki-e , pietra dura , cloisonné , set gemstones or applied 5-minute markings made of different metals are used Application. In the case of an open dial , the numbers are usually reduced to an outer ring to show the movement and its finissage , e.g. B. at the Marie-Antoinette of Abraham Louis Breguet . With a skeleton watch , the dial is reduced to applied indices or is left out entirely to allow an unrestricted view of the movement.
The largest tower dial in Europe is located on the steeple of St. Peter's Church in Zurich , the outer diameter is 8.64 meters.
The largest clock faces in the world are located in the Abraj Al Bait Towers in Mecca, built in 2012 . The four dials point in the four cardinal directions and each have a diameter of 43 meters.
The dials of the station clocks in Germany received an additional number ring from 1927 with the times from 1 p.m. to midnight. The pocket watches used by railroad workers for work also received these additional digits.
Occasionally, further scalings are applied to dials, e.g. B. for total station or pulsometer .
The German word "dial" has found its way into the Russian , Bulgarian and Ukrainian languages as a loan word (Циферблат)
Representation of IIII or IV
There are several theories about the representation of the number 4 as IIII instead of IV in Roman numerals on dials, although the 9 is represented as IX:
- The Jupiter Argument : One reason for this is that IV is the abbreviation for the Roman god Jupiter (IVPITER). This is countered by the fact that Jupiter was hardly revered after the end of the Roman Empire and that the subtraction spelling only became established in the Middle Ages, and it is also unusual in epigraphy .
- The traditional argument : Many clocks use IIII because it corresponds to the representation on some of the oldest surviving clocks. Wells Cathedral clock was built between 1386 and 1392. She used the IIII because the subtraction notation became common only in the late Middle Ages and IIII or IIIJ was mostly used in contemporary manuscripts. These watches have an asymmetrical dial with a 24-hour division. The clocks of the 14th century have different representations, however, the church clock of Ottery St Mary has a 24-hour dial with IV and that of St Albans a 12-hour dial with IIII.
- The Sun King argument : Louis XIV , the King of France, preferred IIII to IV, and instructed his watchmaker to make watches with IIII instead of IV.
- The typographical argument : Since the IV and VI are close to each other and upside down, the IIII is used typographically to avoid confusion .
- The Symmetry Argument : Using the IIII increases the symmetry with the VIII of the dial. Furthermore, the first four digits consist exclusively of I, followed by four digits with V, followed by four digits with X, which further increases the symmetry.
- The manufacturing argument : When using the IIII, 20 I, 4 V and 4 X are required for casting, while IV 17 I, 5 V and 4 X are required. Since 20 is an integer multiple of 4, in the first case you only need a mold with 5 I, 1 V and 1 X, which is then used four times:
- V IIII IX
- VI II IIX
- VII III X
- VIII I IX
gallery
- different dials
Clock in the municipal cattle and slaughterhouse ( Dresden )
Dial of a medieval tower clock, Colmar
One-hand clock at the Freiburg Minster
24 hour clock face in Curitiba, Brazil
Dial of a Zenith El Primero with full calendar
Pocket watch dial without indices, Zenith-Movado approx. 1985
Clock face at the St. Anna Church, Neuenkirchen
Station clock in Kings Cross, London
French decimal dial
French decimal dial with additional 12-hour division
Clock with 24-hour division in the Doge's Palace , Venice
Rotating dial, 15th century, Church of St. Mary, Gdańsk, Poland
Shepherd gate clock at the Royal Greenwich Observatory with 24-hour division
Astronomical dial of the Prague City Hall clock
Railway pocket watch with 24-hour dial (from 1927)
Dial a Gustav Becker - grandfather clock (1910)
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See also
Web links
Individual evidence
- ↑ Display of the time by the sun on a dial see sundial .
- ↑ Don Haven Lathrop: Why is clockwise Clockwise? ( en ) In: Workshop Hints . British Horological Institute. 1996. Archived from the original on May 16, 2008. Retrieved May 8, 2010.
- ↑ Willis I. Milham: Time and Time Keepers: Including the History, Construction, Care, and Accuracy of Clocks and Watches . Omnigraphics Inc, New York 1945, ISBN 0-7808-0008-7 , pp. 195 .
- ↑ Fritz Osterhausen: Callweys lexicon / Fritz von Osterhausen. Photo selection: Christian Pfeiffer-Belli . Callwey, Munich 1999, ISBN 3-7667-1353-1 , p. 272 .
- ↑ Church tower and clockwork . In: Church of St. Peter . Evangelical Reformed Parish of St. Peter, Zurich. Retrieved May 9, 2010.
- ↑ Wolfgang Hoffmann: Is it IIII o'clock or IV o'clock? . In: UhrenH @ nse . February 5, 2009. Retrieved May 15, 2010.
- ↑ http://www.voxinghistory.com/?tag=roman_numerals , accessed on January 15, 2012.
- ^ Paul Lewis: Clocking the fours: A new theory about IIII , accessed January 15, 2012.
- ^ The Wells Cathedral Clock ( March 31, 2014 memento on the Internet Archive ), accessed January 15, 2012.
- ↑ WI Milham: Time & Timekeepers , Macmillan, New York 1947, p 196
- ↑ FAQ: Roman IIII vs. IV on Clock Dials - Donn Lathrop's page on IIII vs. IV , accessed January 15, 2012.