|
|
Line 39: |
Line 39: |
| {{Main|Mainspring}} | | {{Main|Mainspring}} |
| Traditional mechanical watch movements use a spiral spring called a [[mainspring]] as a power source. In ''manual watches'' the spring must be rewound periodically by the user by turning the watch crown. Antique [[pocketwatch]]es were wound by inserting a separate key into a hole in the back of the watch and turning it. Most modern watches are designed to run 40 hours on a winding and thus must be wound daily, but some run for several days and a few have 192-hour mainsprings and are wound weekly. | | Traditional mechanical watch movements use a spiral spring called a [[mainspring]] as a power source. In ''manual watches'' the spring must be rewound periodically by the user by turning the watch crown. Antique [[pocketwatch]]es were wound by inserting a separate key into a hole in the back of the watch and turning it. Most modern watches are designed to run 40 hours on a winding and thus must be wound daily, but some run for several days and a few have 192-hour mainsprings and are wound weekly. |
− |
| |
− | ==Functions==
| |
− | [[File:Rolex-Submariner.jpg|thumb|upright|left|The [[Rolex]] Submariner, an officially certified chronometer]]
| |
− | [[File:Breguet MG 2573.jpg|thumb|upright|left|A [[Breguet (watch)|Breguet]] squelette watch 2933 with [[tourbillon]]]]
| |
− | [[File:Patek-Philippe MG 2583.jpg|thumb|upright|left|Perpetual calendar and moonphase wristwatch by [[Patek Philippe]]]]
| |
− | Customarily, watches provide the [[time of day]], giving at least the hour and minute, and often the second. Many also provide the current date, and some (called "complete calendar" or "triple date" watches) display the day of the week and the month as well. However, many watches also provide a great deal of information beyond the basics of time and date. Some watches include [[alarm]]s. Other elaborate and more expensive watches, both pocket and wrist models, also incorporate [[Striking clock|striking mechanisms]] or [[Repeater (horology)|repeater]] functions, so that the wearer could learn the time by the sound emanating from the watch. This announcement or striking feature is an essential characteristic of true clocks and distinguishes such watches from ordinary [[Clock|timepieces]]. This feature is available on most digital watches.
| |
− |
| |
− | A ''complicated watch'' has one or more functions beyond the basic function of displaying the time and the date; such a functionality is called a [[Complication (horology)|complication]]. Two popular complications are the '''[[chronograph]]''' complication, which is the ability of the watch movement to function as a [[stopwatch]], and the '''moonphase''' complication, which is a display of the [[lunar phase]]. Other more expensive complications include [[Tourbillon]], [[Perpetual calendar]], [[Minute repeater]], and [[Equation of time]]. A truly complicated watch has many of these complications at once (see [[Calibre 89]] from [[Patek Philippe]] for instance). Some watches can both indicate the [[Qibla compass|direction of Mecca]]<ref>{{cite web|title=Muslim watches |url=http://www.watchismo.com/search.aspx?find=muslim |publisher=Watchismo |accessdate=14 April 2012 |url-status=dead |archiveurl=https://web.archive.org/web/20150928004218/http://www.watchismo.com/search.aspx?find=muslim |archivedate=28 September 2015 }}</ref> and have alarms that can be set for all daily prayer requirements.<ref>{{cite web|title=Islamic Watch & Clock|url=http://www.alfajr.com|publisher=ALFAJR|accessdate=14 April 2012}}</ref> Among watch enthusiasts, complicated watches are especially collectible. Some watches include a second 12-hour or 24-hour display for [[UTC]] or [[GMT]].
| |
− |
| |
− | The similar-sounding terms '''chronograph''' and '''chronometer''' are often confused, although they mean altogether different things. A chronograph is a watch with an added duration timer, often a [[stopwatch]] complication (as explained above), while a [[chronometer watch]] is a timepiece that has met an industry standard test for performance under pre-defined conditions: a chronometer is a high quality mechanical or a thermo-compensated movement that has been tested and certified to operate within a certain standard of accuracy by the [[COSC]] (Contrôle Officiel Suisse des Chronomètres). The concepts are different but not mutually exclusive; so a watch can be a chronograph, a chronometer, both, or neither.
| |
− |
| |
− | [[File:Datalink USB Dress Edition.JPG|thumb|upright|Timex Datalink USB Dress edition from 2003 with a dot matrix display; the ''Invasion'' video game is on the screen]]
| |
− |
| |
− | Many computerized wristwatches have been developed, but none have had long-term sales success, because they have awkward [[user interface]]s due to the tiny screens and buttons, and short battery life. As miniaturized electronics became cheaper, watches have been developed containing [[calculator watch|calculators]], [[tonometer]]s, [[barometer]]s, [[altimeter]]s, a [[compass]] using both hands to show the N/S direction, [[video game]]s, [[digital camera]]s, [[keydrive]]s, [[GPS watch|GPS receivers]] and [[cellular phone]]s. A few [[Astronomical clock#Watches|astronomical watches]] show [[phase of the Moon]] and other celestial phenomena. In the early 1980s [[Seiko]] marketed a watch with a television in it. Such watches have also had the reputation as unsightly and thus mainly [[geek]] toys. Several companies have however attempted to develop a [[computer]] contained in a wristwatch (see also [[wearable computer]]).
| |
− |
| |
− | Electronic sports watches, combining timekeeping with GPS and/or [[Activity tracker|activity tracking]], address the general [[Physical fitness|fitness]] market and have the potential for commercial success ([[Garmin forerunner]], Garmin Vivofit, Epson,<ref name="Epson" /> announced model of [[Swatch]] Touch series<ref>Hug, Daniel : ''Swatch lanciert 2015 eine intelligente Uhr.'' In: ''NZZ am Sonntag'', 27 July 2014, page 26 (German)</ref>).
| |
− |
| |
− | [[Braille watch]]es have analog displays with raised bumps around the face to allow blind users to tell the time. Their digital equivalents use [[synthesised speech]] to speak the time on command.
| |
− |
| |
− | === Fashion ===
| |
− | Wristwatches and antique pocket watches are often appreciated as [[jewelry]] or as [[collectible]] works of [[art]] rather than just as timepieces.<ref name=NYT012113>{{cite news|title=Buying Back a Forgotten Chinese Heritage|url=https://www.nytimes.com/2013/01/21/fashion/21iht-acaw-pocket21.html|accessdate=22 January 2013|newspaper=The New York Times|date=21 January 2013|author=Nazanin Lankarani|quote=We try to explain why it makes sense to spend $500,000 on a watch.}}</ref> This has created several different markets for wristwatches, ranging from very inexpensive but accurate watches (intended for no other purpose than telling the correct time) to extremely expensive watches that serve mainly as personal adornment or as examples of high achievement in miniaturization and precision mechanical engineering.
| |
− |
| |
− | Traditionally, dress watches appropriate for [[informal attire|informal]] (business), [[semi-formal]], and [[formal wear|formal]] attire are [[gold]], thin, simple, and plain, but increasingly rugged, [[Complication (horology)|complicated]], or sports watches are considered by some to be acceptable for such attire. Some dress watches have a [[cabochon]] on the crown or [[facet]]ed [[gemstone]]s on the face, [[bezel setting|bezel]], or bracelet. Some are made entirely of faceted [[sapphire]] ([[corundum]]).
| |
− |
| |
− | Many fashions and [[department store]]s offer a variety of less-expensive, trendy, "[[costume jewelry|costume]]" watches (usually for women), many of which are similar in quality to basic quartz timepieces but which feature bolder designs. In the 1980s, the Swiss [[Swatch]] company hired graphic designers to redesign a new annual collection of non-repairable watches.
| |
− |
| |
− | Trade in [[counterfeit watch]]es, which mimic expensive brand-name watches, constitutes an estimated {{USD|1 billion}} market per year.<ref>{{cite web|url=http://www.havocscope.com/counterfeit-watches-market-value/|title=Havocscope Counterfeit Watches Market Value: $1 billion}}</ref>
| |
− |
| |
− | === Space ===
| |
− | [[File:OMEGA-Speedmaster-Professional-Front.jpg|thumb|left|The [[Omega Speedmaster]], selected by [[NASA]] for use on space missions in the 1960s.]]
| |
− |
| |
− | The [[Weightlessness|zero-gravity]] environment and other extreme conditions encountered by [[astronaut]]s in [[Outer space|space]] require the use of specially tested watches.
| |
− |
| |
− | The first ever watch to be sent into space was a Russian "[[Pobeda (watch)|Pobeda]]" watch from the [[Petrodvorets Watch Factory]]. It was sent on a single orbit flight on the spaceship [[Korabl-Sputnik 4]] on 9 March 1961. The watch had been attached without authorisation to the wrist of Chernuchka, a dog that successfully did exactly the same trip as Yuri Gagarin, with exactly the same rocket and equipment, just a month before Gagarin's flight.<ref>{{cite book |title=Animals in Space: From Research Rockets to the Space Shuttle |edition=illustrated |first1=Colin |last1=Burgess |first2=Chris |last2=Dubbs |publisher=Springer Science & Business Media |year=2007 |isbn=978-0-387-49678-8 |page=213 |url=https://books.google.com/books?id=xSdHVIpsrKkC}} [https://books.google.com/books?id=xSdHVIpsrKkC&pg=PA213 Extract of page 213]</ref>
| |
− |
| |
− | On 12 April 1961, [[Yuri Gagarin]] wore a Shturmanskie (a transliteration of ''Штурманские'' which actually means "navigator's") wristwatch during his historic first flight into space. The Shturmanskie was manufactured at the [[Poljot|First Moscow Factory]]. Since 1964, the watches of the First Moscow Factory have been marked by the trademark "Полёт", transliterated as "POLJOT", which means "flight" in [[Russian language|Russian]] and is a tribute to the many space trips its watches have accomplished. In the late 1970s, [[Poljot]] launched a new [[Chronometer watch|chrono]] movement, the 3133. With a 23 jewel movement and manual winding (43 hours), it was a modified Russian version of the [[Switzerland|Swiss]] [[Valjoux]] 7734 of the early 1970s. [[Poljot]] 3133 were taken into space by [[astronaut]]s from Russia, France, Germany and [[Ukraine]]. On the arm of [[Valeriy Polyakov]], a [[Poljot]] 3133 chronograph movement-based watch set a space [[World record|record]] for the longest space flight in history.<ref>{{cite web|url=http://www.netgrafik.ch/russian_space_watches.htm |title=Russian Space Watches History |publisher=Netgrafik.ch |date= |accessdate=27 May 2012}}</ref>
| |
− |
| |
− | [[File:Sts088-359-037.jpg|thumb|Astronaut [[Nancy J. Currie]] wears the Timex Ironman Triathlon Datalink model 78401 during [[STS 88]].]]
| |
− |
| |
− | Through the 1960s, a large range of watches was tested for durability and precision under extreme [[temperature]] changes and vibrations. The [[Omega Speedmaster]] Professional was selected by NASA, the U.S space agency, and it is mostly known thanks to astronaut [[Buzz Aldrin]] who wore it during the moon landing, 1969. [[TAG Heuer|Heuer]] became the first Swiss watch in space thanks to a Heuer Stopwatch, worn by [[John Glenn]] in 1962 when he piloted the [[Friendship 7]] on the first manned U.S. orbital mission. The [[Breitling SA|Breitling]] Navitimer Cosmonaute was designed with a [[24-hour analog dial]] to avoid confusion between AM and PM, which are meaningless in space. It was first worn in space by U.S. astronaut [[Scott Carpenter]] on 24 May 1962 in the [[Aurora 7]] mercury capsule.<ref>{{cite web|url=http://www.breitling.com/en/models/navitimer/cosmonaute/|title=Navitimer, the aviator favourite watch|work=[[Breitling SA|Breitling]]|accessdate=17 January 2007}}</ref>
| |
− |
| |
− | Since 1994 [[Fortis Uhren AG|Fortis]] is the exclusive supplier for manned space missions authorized by the [[Russian Federal Space Agency]]. [[China National Space Administration]] (CNSA) astronauts wear the [[Fiyta]]<ref>{{cite web|url=http://www.fiyta.com.cn|title=Fiyta.com.cn|work=Fiyta|accessdate=17 January 2007|archive-url=https://web.archive.org/web/20070115191903/http://www.fiyta.com.cn/|archive-date=15 January 2007|url-status=dead}}</ref> spacewatches. At [[BaselWorld]], 2008, [[Seiko]] announced the creation of the first watch ever designed specifically for a space walk, Spring Drive Spacewalk. [[Timex Datalink]] is flight certified by [[NASA]] for space missions and is one of the watches qualified by NASA for space travel. The [[Casio]] [[G-Shock]] DW-5600C and 5600E, DW 6900, and DW 5900 are Flight-Qualified for NASA space travel.<ref name="NASA 5-8 Article">{{cite web |url=http://www.nasaexplores.com/show2_5_8a.php?id=02-024&gl=58 |archive-url=https://archive.is/20061114025319/http://www.nasaexplores.com/show2_5_8a.php?id=02-024&gl=58 |url-status=dead |archive-date=14 November 2006 |title=Internet Archive Wayback Machine |date=14 November 2006 |accessdate=23 October 2011 |df=dmy-all }}</ref><ref name="NASA 9-12">{{cite web |url=http://www.nasaexplores.com/search_nav_9_12.php?id=02-024&gl=912 |archive-url=https://archive.is/20080304191551/http://www.nasaexplores.com/search_nav_9_12.php?id=02-024&gl=912 |url-status=dead |archive-date=4 March 2008 |title=Internet Archive Wayback Machine |date=4 March 2008 |accessdate=23 October 2011 |df=dmy-all }}</ref>
| |
− |
| |
− | Various Timex Datalink models were used both by cosmonauts and astronauts.
| |
− |
| |
− | === Scuba diving ===
| |
− | [[File:Seiko 7002-7020 Diver's 200 m on a 4-ring NATO style strap.JPG|thumb|upright|Seiko 7002–7020 Diver's 200 m on a 4-ring NATO style strap]]
| |
− |
| |
− | Watches may be crafted to become water resistant. These watches are sometimes called [[diving watches]] when they are suitable for [[scuba diving]] or [[saturation diving]]. The [[International Organization for Standardization]] issued a standard for water resistant watches which also prohibits the term "[[waterproof]]" to be used with watches, which many countries have adopted.
| |
− |
| |
− | Water resistance is achieved by the [[gasket]]s which forms a watertight seal, used in conjunction with a sealant applied on the case to help keep water out. The material of the case must also be tested in order to pass as water resistant.<ref>{{cite web|url= http://www.europastar.com/europastar/watch_tech/waterresistance.jsp|title=Watch Industry Questions and Answers: Water-Resistance|work=Europa Star|publisher=VNU eMedia Inc|accessdate=17 January 2007}}</ref>
| |
− |
| |
− | None of the tests defined by [[ISO 2281]] for the Water Resistant mark are suitable to qualify a watch for scuba diving. Such watches are designed for everyday life and must be water resistant during exercises such as swimming. They can be worn in different temperature and pressure conditions but are under no circumstances designed for scuba diving.
| |
− |
| |
− | The standards for diving watches are regulated by the [[ISO 6425]] international standard. The watches are tested in static or still water under 125% of the rated (water) pressure, thus a watch with a 200-metre rating will be water resistant if it is stationary and under 250 metres of static water. The testing of the water resistance is fundamentally different from non-dive watches, because every watch has to be fully tested. Besides water resistance standards to a minimum of 100-metre depth rating ISO 6425 also provides eight minimum requirements for mechanical diver's watches for scuba diving (quartz and digital watches have slightly differing readability requirements). For diver's watches for mixed-gas saturation diving two additional requirements have to be met.
| |
− |
| |
− | Watches are classified by their degree of water resistance, which roughly translates to the following (1 metre = 3.281 feet):<ref>{{cite web|url=http://www.jwnz.co.nz/page/watches.aspx|title=Watches|website=Jwnz.co.nz|accessdate=28 October 2017}}</ref>
| |
− |
| |
− | {| class="wikitable"
| |
− | |+ Main Article [[ISO 6425#Water resistance classification|ISO 6425]]
| |
− | |-
| |
− | ! nowrap="nowrap" |Water-resistance rating || Suitability || Remarks
| |
− | |-
| |
− | | Water Resistant or 30 m || Suitable for everyday use. Splash/rain resistant. || NOT suitable for diving, swimming, snorkeling, water-related work, or fishing.
| |
− | |-
| |
− | | Water Resistant 50 m || Suitable for swimming, white-water rafting, non-snorkeling water related work, and fishing. || NOT suitable for diving.
| |
− | |-
| |
− | | Water Resistant 100 m || Suitable for recreational surfing, swimming, snorkeling, sailing, and water sports. || NOT suitable for diving.
| |
− | |-
| |
− | | Water Resistant 200 m || Suitable for professional marine activity and serious surface water sports. || Suitable for diving.
| |
− | |-
| |
− | | Diver's 100 m || Minimum ISO standard for [[scuba diving]] at depths not requiring helium gas. || Diver's 100 m and 150 m watches are generally old(er) watches.
| |
− | |-
| |
− | | Diver's 200 m or 300 m || Suitable for scuba diving at depths not requiring helium gas. || Typical ratings for contemporary diver's watches.
| |
− | |-
| |
− | | Diver's 300<sup>+</sup> m helium safe|| Suitable for [[saturation diving]] (helium-enriched environment). || Watches designed for helium mixed-gas diving will have additional markings to point this out.
| |
− | |}
| |
− |
| |
− | Some watches use [[Bar (unit)|bar]] instead of meters, which may then be multiplied by 10, and then subtract 10 to be approximately equal to the rating based on metres. Therefore, a 5 bar watch is equivalent to a 40-metre watch. Some watches are rated in [[Atmosphere (unit)|atmospheres]] (atm), which are roughly equivalent to bar.
| |
− |
| |
− | === Navigation ===
| |
− | {{Main|Cardinal direction#Watch dial}}
| |
− | There is a traditional method by which an [[analog watch]] can be used to locate north and south. The Sun appears to move in the sky over a 24-hour period while the hour hand of a 12-hour [[clock face]] takes twelve hours to complete one rotation. In the northern hemisphere, if the watch is rotated so that the hour hand points toward the Sun, the point halfway between the hour hand and 12 o'clock will indicate south. For this method to work in the southern hemisphere, the 12 is pointed toward the Sun and the point halfway between the hour hand and 12 o'clock will indicate north. During [[daylight saving time]], the same method can be employed using 1 o'clock instead of 12. This method is accurate enough to be used only at fairly high latitudes.
| |
| | | |
| == See also == | | == See also == |
Early History
Watches evolved from portable Mainspring and spring-driven clocks, which first appeared in 15th century Europe. Watches were not widely worn in pockets until the 17th century. One account says that the word "watch" came from the Old English word woecce which meant "watchman", because it was used by town watchmen to keep track of their shifts at work. Another says that the term came from 17th century sailors, who used the new mechanisms to time the length of their shipboard watches (duty shifts).
The 17th Century -Balance Spring
A great leap forward in accuracy occurred in 1657 with the addition of the balance spring to the balance wheel, an invention disputed both at the time and ever since between Robert Hooke and Christiaan Huygens. This innovation increased watches' accuracy enormously, reducing error from perhaps several hours per day to perhaps 10 minutes per day. Christiaan Huygens published in his letter in the Journal des Sçavants of 25 February 1675 the application of the spiral balance spring for watches which ushered in a new era of accuracy for portable timekeepers, similar to that which the pendulum had introduced for clocks.The spiral balance spring revolutionized the accuracy of watches, enabling them to keep time to within a minute a day. This advance sparked an almost immediate rise in the market for watches, which were now no longer typically worn on a chain around the neck but were carried in a pocket, a wholly new fashion in clothing.
The increased accuracy of the balance wheel focused attention on errors caused by other parts of the movement, igniting a two-century wave of watchmaking innovation. The first thing to be improved was the escapement. The verge escapement was replaced in quality watches by the cylinder escapement, invented by Thomas Tompion in 1695 and further developed by George Graham in the 1720s. Improvements in manufacturing such as the tooth-cutting machine devised by Robert Hooke allowed some increase in the volume of watch production, although finishing and assembling was still done by hand until well into the 19th century.
The 18th Century- Bimetallic Compensator
A major cause of error in balance wheel timepieces, caused by changes in elasticity of the balance spring from temperature changes, was solved by the bimetallic temperature compensated balance wheel invented in 1765 by Pierre Le Roy and improved by Thomas Earnshaw. The lever escapement was the single most important technological breakthrough, and was invented by Thomas Mudge in 1759 and improved by Josiah Emery in 1785, although it only gradually came into use from about 1800 onwards, chiefly in Britain. The British had predominated in watch manufacture for much of the 17th and 18th centuries, but maintained a system of production that was geared towards high-quality products for the elite only.
The 19th Century and Mass Production Arrives
Although there was an attempt to modernise clock manufacture with mass production techniques and the application of duplicating tools and machinery by the British Watch Company in 1843, it was in the United States that this system took off. Aaron Lufkin Dennison started a factory in 1851 in Massachusetts that used interchangeable parts, and by 1861 it was running a successful enterprise incorporated as the Waltham Watch Company.
The Wristwatch
The concept of the wristwatch goes back to the production of the very earliest watches in the 16th century. Elizabeth I of England received a wristwatch from Robert Dudley, 1st Earl of Leicester in 1571, described as an armed watch. The oldest surviving wristwatch (then described as a bracelet watch) is one made in 1806 and given to Joséphine de Beauharnais. From the beginning, wristwatches were almost exclusively worn by women, while men used pocket watches up until the early 20th century.
First Military Use of Watches
Wristwatches were first worn by military men towards the end of the 19th century, when the importance of synchronizing actions during battle, without potentially revealing the plan to the enemy through signaling, was increasingly recognized. The Garstin Company of London patented a "Watch Wristlet" design in 1893, but they were probably producing similar designs from the 1880s. Officers in the British Army began using wristwatches during colonial military campaigns in the 1880s, such as during the Third Anglo-Burmese War of 1885.The company Mappin & Webb began production of their successful "campaign watch" for soldiers during the Battle of Omdurman and accelerated production for the Second Boer War a few years later. In continental Europe, Girard Perregaux and other Swiss watchmakers began supplying German naval officers with wristwatches in about 1880.
Early models were essentially standard pocket-watches fitted to a leather strap but, by the early 20th century, manufacturers began producing purpose-built wristwatches. The Swiss company Dimier Frères & Cie patented a wristwatch design with the now standard wire lugs in 1903. Hans Wilsdorf moved to London in 1905 and set up his own business, Wilsdorf & Davis, with his brother-in-law Alfred Davis, providing quality timepieces at affordable prices; the company later became Rolex.
WW1 and rapid development
The impact of the First World War dramatically shifted public perceptions of of the man's wristwatch and opened up a mass market in the postwar era. Service watches produced during the War were specially designed for the rigours of trench warfare, with luminous dials and unbreakable glass. The War Office began issuing wristwatches to combatants from 1917.By the end of the war, almost all enlisted men wore a wristwatch and after they were demobilized, the fashion soon caught on. See WW1 Military Watches for a more detailed exploration of this area.
1920s onwards
By 1930, the ratio of a wrist to pocket watches was 50 to 1. The first successful self-winding system was invented by John Harwood in 1923.
Hamilton Electric
Hamilton Electric were the pioneers of the first electric watch . Unlike the Quartz and the Bulova Accutron this was the first movement to use a battery as a source to oscillate the balance wheel. Hamilton released two models of the Electric: the first released was the Hamilton 500 on 3 January 1957, which was produced into 1959. This model had problems with the contact wires misaligning and the watch returned to Hamilton for alignment. The Hamilton 505 was an improvement on the 500 and was more reliable: the contact wires were removed and a non-adjustable contact on the balance assembly delivered the power to the balance wheel.
Quartz
The commercial introduction of the quartz watch in 1969 in the form of the Omega Beta 21 and the Seiko Astron was a revolutionary improvement in watch technology. In place of a balance wheel which oscillated at perhaps 5 or 6 beats per second, they used a quartz crystal resonator which vibrated at 8,192 Hz, driven by a battery-powered electronic oscillator. Since the 1980s, more quartz watches than mechanical ones have been marketed.
Tuning-fork watches use a type of electromechanical movement. Introduced by Bulova in 1960, they use a tuning fork with a precise frequency (most often 360 hertz) to drive a mechanical watch. The task of converting electronically pulsed fork vibration into rotary movements is done via two tiny jeweled fingers, called pawls. Tuning-fork watches were rendered obsolete when electronic quartz watches were developed. Quartz watches were cheaper to produce besides being more accurate.
Template:Main
Traditional mechanical watch movements use a spiral spring called a mainspring as a power source. In manual watches the spring must be rewound periodically by the user by turning the watch crown. Antique pocketwatches were wound by inserting a separate key into a hole in the back of the watch and turning it. Most modern watches are designed to run 40 hours on a winding and thus must be wound daily, but some run for several days and a few have 192-hour mainsprings and are wound weekly.
See also
Template:Portal
Template:Clear
Template:Div col
Template:Div col end
References
Template:Reflist
Further reading
- Beckett, Edmund, A Rudimentary Treatise on Clocks, Watches and Bells, 1903, from Project Gutenberg
- Berner, G.A., Illustrated Professional Dictionary of Horology, Federation of the Swiss Watch Industry FH 1961–2012
- Daniels, George, Watchmaking, London: Philip Wilson Publishers, 1981 (reprinted 15 June 2011)
- De Carle, Donald, (Illustrations by E. A. Ayres), Practical Watch Repairing, 3rd edition, New York : Skyhorse Pub., 2008. Template:ISBN. Significant information on watches, their history, and inner workings.
- Denn, Mark, "The Tourbillon and How It Works", IEEE Control Systems Magazine, June 2010, IEEE Control Systems Society, DOI 10.1109/MCS.2010.936291.
- Grafton, Edward, Horology, a popular sketch of clock and watch making, London: Aylett and Jones, 1849
External links
Template:Wiktionary
Template:Commons category
Template:Jewellery
Template:Time measurement and standards
Template:Time topics
Template:Authority control