title: Manual transmission

text: Many of the first automobiles were rear-engined, with a simple belt-drive functioning as a single-speed transmission. The 1891 Panhard et Levassor is considered a significant advance in automotive transmissions since it used a three-speed manual transmission. This transmission, along with many similar designs that it inspired, was a non-synchronous (also called "sliding-mesh") design where gear changes involved sliding the gears along their shafts so that the desired cogs became meshed. The driver was therefore required to use careful timing and throttle manipulation when shifting, so the gears would be spinning at roughly the same speed when engaged; otherwise, the teeth would refuse to mesh. This was difficult to achieve, so gear changes were often accompanied by grinding or crunching sounds, resulting in the gearboxes being nicknamed "crash boxes". Even after passenger cars had switched to synchronous transmissions (i.e. with synchronizers), many transmissions for heavy trucks, motorcycles and racing cars remained non-synchronous, in order to withstand the forces required or provide a faster shift time.


title: Manual transmission

text: The first car to use a manual transmission with synchromesh was the 1929 Cadillac, however most cars continued to use non-synchronous transmissions until at least the 1950s. In 1947, Porsche patented the "split ring" synchromesh system, which went on the become the most common design for passenger cars. The 1952 Porsche 356 was the first car to use a transmission with synchromesh on all forward gears. In the early 1950s, most cars only had synchromesh for the shift from third gear to second gear (drivers' manuals in vehicles suggested that if the driver needed to shift from second to first, it was best to come to a complete stop beforehand).


title: Manual transmission

text: Up until the late 1970s, most transmissions had three or four forward gear ratios, although five-speed manual transmissions were occasionally used in sports cars such as the 1948 Ferrari 166 Inter and the 1953 Alfa Romeo 1900 Super Sprint. Five-speed transmissions became widespread during the 1980s, as did the use of synchromesh on all forward gears.


title: Manual transmission

text: Six-speed manual transmissions started to emerge in high-performance vehicles in the early 1990s, such as the 1990 BMW 850i and the 1992 Ferrari 456. The first 6-speed manual transmission was introduced in the 1967 Alfa Romeo 33 Stradale. The first 7-speed manual transmission was introduced in the 2012 Porsche 911 (991).


title: Manual transmission

text: In 2008, 75.2% of vehicles produced in Western Europe were equipped with manual transmission, versus 16.1% with automatic and 8.7% with other.


title: Manual transmission

text: A manual transmission has several shafts with various gears and other components attached to them. Most modern passenger cars use 'constant-mesh' transmissions consisting of three shafts: an "input shaft", a "countershaft" (also called a layshaft) and an "output shaft".


title: Manual transmission

text: The "input shaft" is connected to the engine and spins at engine speed whenever the clutch is engaged. The "countershaft" has gears of various sizes, which are permanently meshed with the corresponding gear on the input shaft. The gears on the "output shaft" are also permanently meshed with a corresponding gear on the countershaft, however, the output shaft gears are able to rotate independently of the output shaft itself (through the use of bearings located between the gears and the shaft). Through the use of collars (operated using the "shift rods"), the speed of the output shaft becomes temporarily locked to the speed of the selected gear. Some transmission designs—such as in the Volvo 850 and S70—have two countershafts, both driving an output pinion meshing with the front-wheel-drive transaxle's ring gear. This allows for a narrower transmission since the length of each countershaft is halved compared with one that contains four gears and two shifters.


title: Manual transmission

text: The fixed and free gears can be mounted on either the input or output shaft or both. For example, a five-speed transmission might have the first-to-second selectors on the countershaft, but the third-to-fourth selector and the fifth selector on the main shaft. This means that when the vehicle is stopped and idling in neutral with the clutch engaged and the input shaft spinning, the third-, fourth-, and fifth-gear pairs do not rotate.


title: Manual transmission

text: When "neutral" is selected, none of the gears on the output shaft are locked to the shaft, allowing the input and output shafts to rotate independently. For reverse gear, an idler gear is used to reverse the direction in which the output shaft rotates. In many transmissions, the input and output shafts can be directly locked together (bypassing the countershaft) to create a 1:1 gear ratio which is referred to as "direct-drive".


title: Manual transmission

text: In a transmission for longitudinal engined vehicles (e.g. most rear-wheel-drive cars), it is common for the input shaft and output shaft to be located on the same axis, since this reduces the torsional forces to which the transmission casing must withstand. The assembly consisting of both the input and output shafts is referred to as the "main shaft" (although sometimes this term refers to just the input shaft or output shaft). Independent rotation of the input and output shafts is made possibly by one shaft being located inside the hollow bore of the other shaft, with a bearing located between the two shafts.


title: Manual transmission

text: In a transmission for transverse engined vehicles (e.g., front-wheel-drive cars), there are usually only two shafts: input and countershaft (sometimes called input and output). The input shaft runs the whole length of the gearbox, and there is no separate input pinion. These transmissions also have an integral differential unit, which is connected via a pinion gear at the end of the counter/output shaft.


title: Manual transmission

text: In a modern constant-mesh manual transmission, the gear teeth are permanently in contact with each other, and dog clutches (sometimes called "dog teeth") are used to select the gear ratio for the transmission. When the dog clutches for all gears are disengaged (i.e. when the transmission is in neutral), all of the gears are able to spin freely around the output shaft. When the driver selects a gear, the dog clutch for that gear is engaged (via the gear selector rods), locking the transmission's output shaft to a particular gear set. This means the output shaft rotates at the same speed as the selected gear, thus determining the gear ratio of the transmission.


title: Manual transmission

text: The dog clutch is a sliding selector mechanism that sits around the output shaft. It has teeth to fit into the splines on the shaft, forcing that shaft to rotate at the same speed as the gear hub. However, the clutch can move back and forth on the shaft, to either engage or disengage the splines. This movement is controlled by a selector fork that is linked to the gear lever. The fork does not rotate, so it is attached to a collar bearing on the selector. The selector is typically symmetric: it slides between two gears and has a synchromesh and teeth on each side in order to lock either gear to the shaft. Unlike some other types of clutches (such as the foot-operated clutch of a manual-transmission car), a dog clutch provides non-slip coupling and is not suited to intentional slipping.


title: Manual transmission

text: In order to provide smooth gearshifts without requiring the driver to manually match the engine revs for each gearshift, most modern passenger car transmissions use 'synchromesh' (also called 'synchronizer rings') on the forward gears. These devices automatically match the speed of the input shaft with that of the gear being selected, thus removing the need for the driver to use techniques such as double-clutching. The synchromesh transmission was invented in 1919 by Earl Avery Thompson and first used on production cars by Cadillac in 1928.


title: Manual transmission

text: The need for synchromesh in a constant-mesh transmission is that the dog clutches require the input shaft speed to match that of the gear being selected; otherwise, the dog teeth will fail to engage and a loud grinding sound will be heard as they clatter together. Therefore, to speed up or slow down the input shaft as required, cone-shaped brass synchronizer rings are attached to each gear. When the driver moves the gearshift lever towards the next gear, these synchronizer rings press on the cone-shaped sleeve on the dog collar so that the friction forces can reduce the difference in rotational speeds. Once these speeds are equalized, the dog clutch can engage, and thus the new gear is now in use. In a modern gearbox, the action of all of these components is so smooth and fast it is hardly noticed. Many transmissions do not include synchromesh on the reverse gear (see Reverse gear section below).


title: Manual transmission

text: The synchromesh system must also prevent the collar from bridging the locking rings while the speeds are still being synchronized. This is achieved through 'blocker rings' (also called 'baulk rings'). The synchro ring rotates slightly because of the frictional torque from the cone clutch. In this position, the dog clutch is prevented from engaging. Once the speeds are synchronized, friction on the blocker ring is relieved and the blocker ring twists slightly, bringing into alignment certain grooves or notches that allow the dog clutch to fall into the engagement.


title: Manual transmission

text: Common metals for synchronizer rings are brass and steel, and are produced either by forging or sheet metal shaping. The latter involves stamping the piece out of a sheet metal strip and then machining to obtain the exact shape required. The rings are sometimes coated with anti-wear linings (also called 'friction linings') made from molybdenum, iron, bronze or carbon (with the latter usually reserved for high-performance transmissions due to their high cost).


title: Manual transmission

text: Mechanical wear of the synchronizer rings and sleeves can cause the synchromesh system to become ineffective over time. These rings and sleeves have to overcome the momentum of the entire input shaft and clutch disk during each gearshift (and also the momentum and power of the engine, if the driver attempts a gearshift without fully disengaging the clutch). Larger differences in speed between the input shaft and the gear require higher friction forces from the synchromesh components, potentially increasing their wear rate.


title: Manual transmission

text: Even in modern transmissions where all of the forward gears are in a constant-mesh configuration, often the reverse gear uses the older "sliding-mesh" ("crash box") configuration. This means that moving the gearshift lever into reverse results in gears moving to mesh together. Another unique aspect of the reverse gear is that it consists of two gears—an idler gear on the countershaft and another gear on the output shaft—and both of these are directly fixed to the shaft (i.e. they are always rotating at the same speed as the shaft). These gears are usually spur gears with straight-cut teeth which—unlike the helical teeth used for forward gear—results in a whining sound as the vehicle moves in reverse.


title: Manual transmission

text: When reverse gear is selected, the idler gear is physically moved to mesh with the corresponding gears on the input and output shafts. To avoid grinding as the gears begin to the mesh, they need to be stationary. Since the input shaft is often still spinning due to momentum (even after the car has stopped), a mechanism is needed to stop the input shaft, such as using the synchronizer rings for 5th gear. However, some vehicles do employ a synchromesh system for the reverse gear, thus preventing possible crunching if reverse gear is selected while the input shaft is still spinning.


title: Manual transmission

text: Most transmissions include a lockout mechanism to prevent reverse gear from being accidentally selected while the car is moving forwards. This can take the form of a collar underneath the gear knob which needs to be lifted or requiring extra force to push the gearshift lever into the plane of reverse gear.


title: Manual transmission

text: Another design of transmission that is used in older cars, trucks, and tractors, is a non-synchronous transmission (also known as a crash gearbox). Non-synchronous transmissions use a sliding-mesh (or constant-mesh, in later years) design and have the nickname "crash" because the difficulty in changing gears can lead to gear shifts accompanied by crashing/crunching noises.


title: Manual transmission

text: Vehicles with manual transmissions use a clutch to manage the linkage between the engine and the transmission, and decouple the transmission from the engine during gearshifts and when the vehicle is stationary. Without a clutch, the engine would stall any time the vehicle stopped, and changing gears would be difficult (deselecting a gear while the transmission requires the driver to adjust the throttle so that the transmission is not under load, and selecting a gear requires the engine RPM to be at the exact speed that matches the road speed for the gear being selected).


title: Manual transmission

text: Most motor vehicles use a pedal to operate the clutch; except for motorcycles, which usually have a clutch lever on the left handlebar.


title: Manual transmission

text: In most vehicles with a manual transmission, the driver selects gears by manipulating a lever called a "gear stick" (also called a "gearshift", "gear lever" or "shifter"). In most automobiles, the gear stick is located on the floor between the driver and front passenger, but some cars have a gear stick that is mounted to the steering column or center console.


title: Manual transmission

text: The movement of the gear stick is transferred (via solid linkages or cables) to the selector forks within the transmission.


title: Manual transmission

text: Motorcycles typically employ sequential manual transmissions, although the shift pattern is modified slightly for safety reasons. Gear selection is usually via the left-foot (or, on older motorcycles; right-foot) shift lever with a layout of


title: Manual transmission

text: In the 1950s, 1960s, and 1970s, fuel-efficient highway cruising with low engine speed was in some cases enabled on vehicles equipped with 3- or 4-speed transmissions by means of a separate overdrive unit in or behind the rear housing of the transmission. This was actuated either manually while in high gear by throwing a switch or pressing a button on the gearshift knob or on the steering column, or automatically by momentarily lifting the foot from the accelerator with the vehicle traveling above a certain road speed. Automatic overdrives were disengaged by flooring the accelerator, and a lockout control was provided to enable the driver to disable overdrive and operate the transmission as a normal (non-overdrive) transmission.


title: Manual transmission

text: The term 'overdrive' is also used to describe a gear with a ratio of less than one (e.g., if the top gear of the transmission has a ratio of 0.8:1).


title: Manual transmission

text: Vehicles with a manual transmission can often be push started when the starter motor is not operational, such as when the car has a dead battery.


title: Manual transmission

text: When push-starting, the energy generated by the wheels moving on the road is transferred to the driveshaft, then the transmission, and eventually the crankshaft. When the crankshaft spins as a result of the energy generated by the rolling of the vehicle, the motor is cranked over. This simulates what the starter is intended for and operates in a similar way to crank handles on very old cars from the early 20th century, with the cranking motion being replaced by the pushing of the car.


title: Manual transmission

text: Recently, many automatic transmissions have included more gear ratios than their manual counterparts.


title: Manual transmission

text: Driving a vehicle with a manual transmission is more difficult than an automatic transmission for several reasons. Firstly, the clutch pedal is an extra control mechanism to operate and in some cases, a "heavy clutch" requires significant force to be operated (this can also preclude some people with injuries or impairments from driving manual transmission vehicles). The operation of the gearstick — another function that is not required on automatic transmission cars — means that the driver must take one hand off the steering wheel while changing gears (unless paddle shift is used). Another challenge is that smooth driving requires co-ordinated timing of the clutch, accelerator, and gearshift inputs. Lastly, a car with an automatic transmission obviously does not require the driver to make any decisions about which gear to use at any given time. On the other hand, being able to choose a specific gear and engine rpm setting manually gives the driver full control of the torque applied by the tires, a critical ability for racing, and important for driving on ice, snow, mud or sand and for spirited driving. Some automatic transmissions have a mode where gears can be manually shifted for such uses.


title: Manual transmission

text: In some countries, a driving license issued for vehicles with an automatic transmission is not valid for driving vehicles with a manual transmission, but a license for manual transmissions covers both.


title: Manual transmission

text: Starting from a stationary position in a manual transmission vehicle requires extra torque to accelerate the vehicle up the hill, with the potential for the vehicle to roll backward in the time it takes to move the driver's foot from the brake pedal to the accelerator pedal (to increase the engine RPM before letting out the clutch). The traditional method of hill starts in a manual transmission car is to use the parking brake (also called "handbrake", "emergency brake", or "e-brake") to hold the vehicle stationary. This means that the driver's right foot is not needed to operate the brake pedal, freeing it up to be used on the accelerator pedal instead. Once the required engine RPM is obtained, the driver can release the clutch, also releasing the parking brake as the clutch engages.


title: Manual transmission

text: A device called the hill-holder was introduced on the 1936 Studebaker. Many modern vehicles use an electronically actuated parking brake, which often includes a hill-holder feature whereby the parking brake is automatically released as the driven wheels start to receive power from the engine.


title: Manual transmission

text: The synchronized down shift rev-matching system is a computer-controlled technology that mimics the manual rev-matching technique.


title: Manual transmission

text: Some trucks have transmissions that look and behave like ordinary consumer vehicle transmissions—these transmissions are used on lighter trucks, typically have up to 6 gears, and usually have synchromesh.


title: Manual transmission

text: For trucks needing more gears, the standard "H" pattern can be complicated for some truck drivers, so additional controls are used to select additional gears. The "H" pattern is retained, then an additional control selects among alternatives. In older trucks, the control is often a separate lever mounted on the floor or more recently a pneumatic switch mounted on the "H" lever; in newer trucks, the control is often an electrical switch mounted on the "H" lever. Multi-control transmissions are built in much higher power ratings but rarely use synchromesh.


title: Manual transmission

text: Although there are many gear positions, shifting through gears usually follows a regular pattern. For example, a series of up shifts might use "move to splitter direct; move to splitter overdrive; move the shift lever to No. 2 and move splitter to underdrive; move splitter to direct; move splitter to overdrive; move the shifter to No. 3 and move splitter to underdrive"; and so on. In older trucks using floor-mounted levers, a bigger problem is common gear shifts require the drivers to move their hands between shift levers in a single shift, and without synchromesh, shifts must be carefully timed or the transmission will not engage. For this reason, some splitter transmissions have an additional "under under" range, so when the splitter is already in "under" it can be quickly downshifted again, without the delay of a double shift.


title: Manual transmission

text: Modern truck transmissions are most commonly "range-splitter". The most common 13-speed has a standard H pattern, and the pattern from the left upper corner is as follows: R, down to L, over and up to 1, down to 2, up and over to 3, down to 4. The "butterfly" range lever in the center front of the knob is flipped up to high range while in 4th, then shifted back to 1. The 1 through 4 positions of the knob is repeated. Also, each can be split using the thumb-actuated under-overdrive lever on the left side of the knob while in high range. The "thumb" lever is not available in low range, except in 18 speeds; 1 through 4 in the low range can be split using the thumb lever and L can be split with the "Butterfly" lever. L cannot be split using the thumb lever in either the 13- or 18-speed. The 9-speed transmission is like a 13-speed without the under-overdrive thumb lever.


title: Manual transmission

text: Truck transmissions use many physical layouts. For example, the output of an N-speed transmission may drive an M-speed secondary transmission, giving a total of N*M gear combinations. Transmissions may be in separate cases with a shaft in between; in separate cases bolted together; or all in one case, using the same lubricating oil. The second transmission is often called a "Brownie" or "Brownie box" after a popular brand. With a third transmission, gears are multiplied yet again, giving greater range or closer spacing. Some trucks thus have dozens of gear positions, although most are duplicates. Sometimes a secondary transmission is integrated with the differential in the rear axle, called a "two-speed rear end". Two-speed differentials are always splitters. In newer transmissions, there may be two counter shafts, so each main shaft gear can be driven from one or the other countershaft; this allows construction with short and robust countershafts, while still allowing many gear combinations inside a single gear case.


title: Manual transmission

text: Heavy-duty transmissions are mostly non-synchromesh. Sometimes synchromesh adds weight that could be payload, and is one more thing to fail, and drivers spend thousands of hours driving so can take the time to learn to drive efficiently with a non-synchromesh transmission. Float shifting (also called "floating gears") is changing gears without disengaging the clutch, usually on a non-synchronized transmission used by large trucks. Since the clutch is not used, it is easy to mismatch speeds of gears, and the driver can quickly cause major (and expensive) damage to the gears and the transmission.


title: Manual transmission

text: Heavy trucks are usually powered with diesel engines. Diesel truck engines from the 1970s and earlier tend to have a narrow power band, so they need many close-spaced gears. Starting with the 1968 Maxidyne, diesel truck engines have increasingly used turbochargers and electronic controls that widen the power band, allowing fewer and fewer gear ratios. As of 2021, fleet operators often use 9, 10, 13, or 18-speed transmissions, but automated manual transmissions are becoming more common on heavy vehicles, as they can improve efficiency and drivability, reduce the barrier to entry for new drivers, and may improve safety by allowing the driver to concentrate on road conditions.


title: Manual transmission

text: Manual transmissions are lubricated with gear oil (or engine oil in some vehicles) which must be changed periodically in some vehicles, although not as frequently as the fluid in an automatic transmission. Gear oil has a characteristic aroma because it contains added sulfur-bearing anti-wear compounds. These compounds are used to reduce the high sliding friction by the helical gear cut of the teeth (this cut eliminates the characteristic whine of straight-cut spur gears). On motorcycles with "wet" clutches (clutch is bathed in engine oil), there is usually nothing separating the lower part of the engine from the transmission, so the same oil lubricates both the engine and transmission.


title: French First Republic

text: In the history of France, the First Republic (), sometimes referred to in historiography as Revolutionary France, and officially the French Republic (), was founded on 21 September 1792 during the French Revolution. The First Republic lasted until the declaration of the First Empire on 18 May 1804 under Napoléon Bonaparte, although the form of the government changed several times.


title: French First Republic

text: This period was characterized by the fall of the monarchy, the establishment of the National Convention and the Reign of Terror, the Thermidorian Reaction and the founding of the Directory, and, finally, the creation of the Consulate and Napoleon's rise to power.


title: French First Republic

text: Under the Legislative Assembly, which was in power before the proclamation of the First Republic, France was engaged in war with Prussia and Austria. In July 1792, the Duke of Brunswick, commanding general of the Austro–Prussian Army, issued his Brunswick Manifesto, threatening the destruction of Paris should any harm come to King Louis XVI of France.


title: French First Republic

text: This foreign threat exacerbated France's political turmoil amid the French Revolution and deepened the passion and sense of urgency among the various factions. In the insurrection of 10 August 1792, citizens rioted the Tuileries Palace, killing six hundred of the King's Swiss guards and insisting on the removal of the king.


title: French First Republic

text: A renewed fear of anti-revolutionary action prompted further violence, and in the first week of September 1792, mobs of Parisians broke into the city's prisons. They killed over half of the prisoners, including nobles, clergymen, and political prisoners, but also common criminals, such as prostitutes and petty thieves. Many victims were murdered in their cells: raped, stabbed, and/or slashed to death. This became known as the September Massacres.


title: French First Republic

text: As a result of the spike in public violence and the political instability of the constitutional monarchy, a party of six members of France's Legislative Assembly was assigned the task of overseeing elections. The resulting Convention was founded with the dual purpose of abolishing the monarchy and drafting a new constitution.


title: French First Republic

text: The convention's first act was to establish the French First Republic and officially strip the king of all political powers. Louis XVI, by then a private citizen bearing his family name of Capet, was subsequently put on trial for crimes of high treason starting in December 1792. On 16 January 1793 he was convicted, and on 21 January, he was executed.


title: French First Republic

text: Throughout the winter of 1792 and spring of 1793, Paris was plagued by food riots and mass hunger. The new Convention did little to remedy the problem until late spring of 1793, occupied instead with matters of war. Finally, on 6 April 1793, the Convention created the Committee of Public Safety, and was given a monumental task: "To deal with the radical movements of the Enragés, food shortages and riots, the revolt in the Vendée and in Brittany, recent defeats of its armies, and the desertion of its commanding general."


title: French First Republic

text: Most notably, the Committee of Public Safety instated a policy of terror, and the guillotine began to fall on perceived enemies of the republic at an ever-increasing rate, beginning the period known today as the Reign of Terror.


title: French First Republic

text: Despite growing discontent with the National Convention as a ruling body, in June the Convention drafted the Constitution of 1793, which was ratified by popular vote in early August. However, the Committee of Public Safety was seen as an "emergency" government, and the rights guaranteed by the 1789 "Declaration of the Rights of Man and of the Citizen" and the new constitution were suspended under its control.


title: French First Republic

text: It could be discussed whether the head of state would have been the president of the National Assembly under international law. However, this changed every two weeks and was therefore not formative.


title: French First Republic

text: After the arrest and execution of Robespierre on 28 July 1794, the Jacobin club was closed, and the surviving Girondins were reinstated. A year later, the National Convention adopted the Constitution of the Year III. They reestablished freedom of worship, began releasing large numbers of prisoners, and most importantly, initiated elections for a new legislative body.


title: French First Republic

text: On 3 November 1795, the Directory was established. Under this system, France was led by a bicameral Parliament, consisting of an upper chamber called the Council of Elders (with 250 members) and a lower chamber called the Council of Five Hundred (with, accordingly, 500 members), and a collective Executive of five members called the Directory (from which the historical period gets its name). Due to internal instability, caused by hyperinflation of the paper monies called Assignats, and French military disasters in 1798 and 1799, the Directory lasted only four years, until overthrown in 1799.


title: French First Republic

text: The French Consulate era began with the coup of 18 Brumaire on 9 November 1799. Members of the Directory itself planned the coup, indicating clearly the failing power of the Directory. Napoleon Bonaparte was a co-conspirator in the coup, and became head of the government as the First Consul.


title: French First Republic

text: On 18 May 1804, Napoleon was proclaimed Emperor of the French by the Sénat conservateur. He would later proclaim himself Emperor of the French, ending the First French Republic and ushering in the French First Empire.


title: Watch

text: A watch is a portable timepiece intended to be carried or worn by a person. It is designed to keep a consistent movement despite the motions caused by the person's activities. A wristwatch is designed to be worn around the wrist, attached by a watch strap or other type of bracelet, including metal bands, leather straps or any other kind of bracelet. A pocket watch is designed for a person to carry in a pocket, often attached to a chain.


title: Watch

text: Watches were developed in the 17th century from spring-powered clocks, which appeared as early as the 14th century. During most of its history the watch was a mechanical device, driven by clockwork, powered by winding a mainspring, and keeping time with an oscillating balance wheel. These are called "mechanical watches". In the 1960s the electronic "quartz watch" was invented, which was powered by a battery and kept time with a vibrating quartz crystal. By the 1980s the quartz watch had taken over most of the market from the mechanical watch. Historically, this is called the quartz revolution (also known as quartz crisis in Switzerland). Developments in the 2010s include "smartwatches", which are elaborate computer-like electronic devices designed to be worn on a wrist. They generally incorporate timekeeping functions, but these are only a small subset of the smartwatch's facilities.


title: Watch

text: In general, modern watches often display the day, date, month, and year. For mechanical watches, various extra features called "complications," such as moon-phase displays and the different types of tourbillon, are sometimes included. Most electronic quartz watches, on the other hand, include time-related features such as timers, chronographs and alarm functions. Furthermore, some modern watches (like smartwatches) even incorporate calculators, GPS and Bluetooth technology or have heart-rate monitoring capabilities, and some of them use radio clock technology to regularly correct the time.


title: Watch

text: Most watches that are used mainly for timekeeping have quartz movements. However, expensive collectible watches, valued more for their elaborate craftsmanship, aesthetic appeal, and glamorous design than for simple timekeeping, often have traditional mechanical movements, despite being less accurate and more expensive than their electronic counterparts. As of 2018, the most expensive watch ever sold at auction was the Patek Philippe Henry Graves Supercomplication, the world's most complicated mechanical watch until 1989, fetching US$24 million (CHF 23,237,000) in Geneva on 11 November 2014. As of December 2019, the most expensive watch ever sold at auction (and wristwatch) was the Patek Philippe Grandmaster Chime Ref. 6300A-010, fetching US$31.19 million (CHF 31,000,000) in Geneva on 9 November 2019.


title: Watch

text: Watches evolved from portable spring-driven clocks, which first appeared in 15th-century Europe. The first timepieces to be worn, made in the 16th century beginning in the German cities of Nuremberg and Augsburg, were transitional in size between clocks and watches. Nuremberg clockmaker Peter Henlein (or Henle or Hele) (1485-1542) is often credited as the inventor of the watch. However, other German clockmakers were creating miniature timepieces during this period, and there is no evidence Henlein was the first.


title: Watch

text: Watches were not widely worn in pockets until the 17th century. One account suggests that the word "watch" came from the Old English word "woecce" - which meant "watchman" – because town watchmen used the technology 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).


title: Watch

text: A rise 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, resulting in the addition of the minute hand to the face from around 1680 in Britain and around 1700 in France.


title: Watch

text: 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.


title: Watch

text: 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 (1749–1829). The lever escapement, the single most important technological breakthrough, though invented by Thomas Mudge in 1759 and improved by Josiah Emery in 1785, only gradually came into use from about 1800 onwards, chiefly in Britain.


title: Watch

text: The British 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 élite. The British Watch Company modernized clock manufacture with mass-production techniques and the application of duplicating tools and machinery in 1843. In the United States, Aaron Lufkin Dennison started a factory in 1851 in Massachusetts that used interchangeable parts, and by 1861 a successful enterprise operated, incorporated as the Waltham Watch Company.


title: Watch

text: The concept of the wristwatch goes back to the production of the very earliest watches in the 16th century. In 1571 Elizabeth I of England received a wristwatch, described as an "armed watch," from Robert Dudley. 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 - men used pocket watches up until the early-20th century. In 1810, the watch-maker Abraham-Louis Breguet made a wristwatch for the Queen of Naples. The first Swiss wristwatch was made by the Swiss watch-maker Patek Philippe, in the year 1868 for Countess Koscowicz of Hungary.


title: Watch

text: Wristwatches were first worn by military men towards the end of the 19th century, having increasingly recognized the importance of synchronizing maneuvers during war without potentially revealing plans to the enemy through signaling. The Garstin Company of London patented a "Watch Wristlet" design in 1893, but probably produced similar designs from the 1880s. Officers in the British Army began using wristwatches during colonial military campaigns in the 1880s, such as during the Anglo-Burma War of 1885. During the First Boer War of 1880–1881 the importance of coordinating troop movements and synchronizing attacks against highly mobile Boer insurgents became paramount, and the use of wristwatches subsequently became widespread among the officer class. The company Mappin & Webb began production of their successful "campaign watch" for soldiers during the campaign in the Sudan in 1898 and accelerated production for the Second Boer War of 1899–1902 a few years later. In continental Europe, Girard-Perregaux and other Swiss watchmakers began supplying German naval officers with wristwatches in about 1880.


title: Watch

text: 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.


title: Watch

text: In 1904, Louis Cartier produced a wristwatch to allow his friend Alberto Santos-Dumont to check flight performance in his airship while keeping both hands on the controls as this proved difficult with a pocket watch. Cartier still markets a line of Santos-Dumont watches and sunglasses.


title: Watch

text: In 1905, Hans Wilsdorf moved to London and set up his own business, Wilsdorf & Davis, with his brother-in-law Alfred Davis, providing quality timepieces at affordable prices; the company became Rolex in 1915. Wilsdorf was an early convert to the wristwatch, and contracted the Swiss firm Aegler to produce a line of wristwatches.


title: Watch

text: The impact of the First World War of 1914–1918 dramatically shifted public perceptions on the propriety of the man's wristwatch and opened up a mass market in the postwar era. The creeping barrage artillery tactic, developed during the war, required precise synchronization between the artillery gunners and the infantry advancing behind the barrage. Service watches produced during the war were specially designed for the rigors 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 (or wristlet), and after they were demobilized the fashion soon caught on: the British "Horological Journal" wrote in 1917 that "the wristlet watch was little used by the sterner sex before the war, but now is seen on the wrist of nearly every man in uniform and of many men in civilian attire." By 1930, the wristwatch vastly exceeded the pocket watch in market share by a decisive ratio of 50:1.


title: Watch

text: John Harwood invented the first successful self-winding system in 1923. In anticipation of Harwood's patent for self-winding mechanisms expiration in 1930, Glycine founder Eugène Meylan started development on a self-winding system as a separate module that could be used with almost any 8.75 ligne (19.74 millimeter) watch movement. Glycine incorporated this module into its watches in October 1930 and began mass-producing automatic watches.


title: Watch

text: The Elgin National Watch Company and the Hamilton Watch Company pioneered the first electric watch. The first electric movements used a battery as a power source to oscillate the balance wheel. During the 1950s Elgin developed the model 725 while Hamilton released two models: the first, the Hamilton 500, released on 3 January 1957, was produced into 1959. This model had problems with the contact wires misaligning, and the watches returned to Hamilton for alignment. The Hamilton 505, an improvement on the 500, proved more reliable: the contact wires were removed and a non-adjustable contact on the balance assembly delivered the power to the balance wheel. Similar designs from many other watch companies followed. Another type of electric watch was developed by the Bulova company that used a tuning-fork resonator instead of a traditional balance wheel to increase timekeeping accuracy, moving from a typical 2.5–4 Hz with a traditional balance wheel to 360 Hz with the tuning-fork design.


title: Watch

text: The commercial introduction of the quartz watch in 1969 in the form of the Seiko Astron 35SQ and in 1970 in the form of the Omega Beta 21 was a revolutionary improvement in watch technology. In place of a balance wheel which oscillated at perhaps 5 or 6 beats per second, these devices used a quartz-crystal resonator which vibrated at 8,192 Hz, driven by a battery-powered oscillator circuit. Most quartz-watch oscillators now operate at 32,768 Hz, although quartz movements have been designed with frequencies as high as 262 kHz. Since the 1980s, more quartz watches than mechanical ones have been marketed.


title: Watch

text: The movement and case are the basic parts of a watch. A watch band or bracelet is added to form a wristwatch; alternatively, a watch chain is added to form a pocket watch.


title: Watch

text: The case back is the back portion of the watch's case. Accessing the movement (such as during battery replacement) depends on the type of case back, which are generally categorized into four types:


title: Watch

text: The crystal, also called the window or watch glass, is the transparent part of the case that allows viewing the hands and the dial of the movement.


title: Watch

text: The lugs are small metal projections at both ends of the wristwatch case where the watch band attaches to the watch case.


title: Watch

text: The movement of a watch is the mechanism that measures the passage of time and displays the current time (and possibly other information including date, month, and day). Movements may be entirely mechanical, entirely electronic (potentially with no moving parts), or they might be a blend of both. Most watches intended mainly for timekeeping today have electronic movements, with mechanical hands on the watch face indicating the time.


title: Watch

text: Compared to electronic movements, mechanical watches are less accurate, often with errors of seconds per day; are sensitive to position, temperature, and magnetism; are costly to produce; require regular maintenance and adjustments; and are more prone to failures. Nevertheless, mechanical watches attract interest from consumers, particularly among watch collectors. Skeleton watches are designed to display the mechanism for aesthetic purposes.


title: Watch

text: A mechanical movement uses an escapement mechanism to control and limit the unwinding and winding parts of a spring, converting what would otherwise be a simple unwinding into a controlled and periodic energy release. The movement also uses a balance wheel, together with the balance spring (also known as a hairspring), to control gear system's motion in a manner analogous to the pendulum of a pendulum clock. The tourbillon, an optional part for mechanical movements, is a rotating frame for the escapement, used to cancel out or reduce gravitational bias. Due to the complexity of designing a tourbillon, they are expensive, and typically found in prestigious watches.


title: Watch

text: The pin-lever escapement (called the Roskopf movement after its inventor, Georges Frederic Roskopf), which is a cheaper version of the fully levered movement, was manufactured in huge quantities by many Swiss manufacturers, as well as by Timex, until it was replaced by quartz movements.


title: Watch

text: Introduced by Bulova in 1960, tuning-fork watches use a type of electromechanical movement with a precise frequency (most often ) 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.


title: Watch

text: Traditional mechanical watch movements use a spiral spring called a mainspring as its power source that must be rewound periodically by the user by turning the watch crown. Antique pocket watches were wound by inserting a key into the back of the watch and turning it. While most modern watches are designed to run on a winding, requiring winding daily, some run for several days; a few have 192-hour mainsprings, requiring once-weekly winding.


title: Watch

text: A "self-winding" or "automatic" watch is one that rewinds the mainspring of a mechanical movement by the natural motions of the wearer's body. The first self-winding mechanism was invented for pocket watches in 1770 by Abraham-Louis Perrelet, but the first "self-winding," or "automatic," wristwatch was the invention of a British watch repairer named John Harwood in 1923. This type of watch winds itself without requiring any special action by the wearer. It uses an eccentric weight, called a winding rotor, which rotates with the movement of the wearer's wrist. The back-and-forth motion of the winding rotor couples to a ratchet to wind the mainspring automatically. Self-winding watches usually can also be wound manually to keep them running when not worn or if the wearer's wrist motions are inadequate to keep the watch wound.


title: Watch

text: In April 2014 the Swatch Group launched the "sistem51" wristwatch. It has a purely mechanical movement consisting of only 51 parts, including a novel self-winding mechanism with a transparent oscillating weight. So far, it is the only mechanical movement manufactured entirely on a fully automated assembly line. The low parts count and the automated assembly make it an inexpensive mechanical Swiss watch, which can be considered a successor to Roskopf movements, although of higher quality.


title: Watch

text: Electronic movements, also known as quartz movements, have few or no moving parts, except a quartz crystal which is made to vibrate by the piezoelectric effect. A varying electric voltage is applied to the crystal, which responds by changing its shape so, in combination with some electronic components, it functions as an oscillator. It resonates at a specific highly stable frequency, which is used to accurately pace a timekeeping mechanism. Most quartz movements are primarily electronic but are geared to drive mechanical hands on the face of the watch to provide a traditional analog display of the time, a feature most consumers still prefer.


title: Watch

text: In 1959 Seiko placed an order with Epson (a subsidiary company of Seiko and the 'brain' behind the quartz revolution) to start developing a quartz wristwatch. The project was codenamed 59A. By the 1964 Tokyo Summer Olympics, Seiko had a working prototype of a portable quartz watch which was used as the time measurements throughout the event.


title: Watch

text: The first prototypes of an electronic quartz wristwatch (not just quartz watches as the Seiko timekeeping devices at the Tokyo Olympics in 1964) were made by the CEH research laboratory in Neuchâtel, Switzerland. From 1965 through 1967 pioneering development work was done on a miniaturized 8192 Hz quartz oscillator, a thermo-compensation module, and an in-house-made, dedicated integrated circuit (unlike the hybrid circuits used in the later Seiko Astron wristwatch). As a result, the BETA 1 prototype set new timekeeping performance records at the International Chronometric Competition held at the Observatory of Neuchâtel in 1967. In 1970, 18 manufacturers exhibited production versions of the beta 21 wristwatch, including the Omega Electroquartz as well as Patek Philippe, Rolex Oysterquartz and Piaget.


title: Watch

text: The first quartz watch to enter production was the Seiko 35 SQ Astron, which hit the shelves on 25 December 1969, swiftly followed by the Swiss Beta 21, and then a year later the prototype of one of the world's most accurate wristwatches to date: the Omega Marine Chronometer. Since the technology having been developed by contributions from Japanese, American and Swiss, nobody could patent the whole movement of the quartz wristwatch, thus allowing other manufacturers to participate in the rapid growth and development of the quartz watch market. This ended - in less than a decade - almost 100 years of dominance by the mechanical wristwatch legacy. Modern quartz movements are produced in very large quantities, and even the cheapest wristwatches typically have quartz movements. Whereas mechanical movements can typically be off by several seconds a day, an inexpensive quartz movement in a child's wristwatch may still be accurate to within half a second per day - ten times more accurate than a mechanical movement.


title: Watch

text: After a consolidation of the mechanical watch industry in Switzerland during the 1970s, mass production of quartz wristwatches took off under the leadership of the Swatch Group of companies, a Swiss conglomerate with vertical control of the production of Swiss watches and related products. For quartz wristwatches, subsidiaries of Swatch manufacture watch batteries (Renata), oscillators (Oscilloquartz, now Micro Crystal AG) and integrated circuits (Ebauches Electronic SA, renamed EM Microelectronic-Marin). The launch of the new SWATCH brand in 1983 was marked by bold new styling, design, and marketing. Today, the Swatch Group maintains its position as the world's largest watch company.


title: Watch

text: Seiko's efforts to combine the quartz and mechanical movements bore fruit after 20 years of research, leading to the introduction of the Seiko Spring Drive, first in a limited domestic market production in 1999 and to the world in September 2005. The Spring Drive keeps time within quartz standards without the use of a battery, using a traditional mechanical gear train powered by a spring, without the need for a balance wheel either.


title: Watch

text: In 2010, Miyota (Citizen Watch) of Japan introduced a newly developed movement that uses a 3-pronged quartz crystal that was exclusively produced for Bulova to be used in the Precisionist or Accutron II line, a new type of quartz watch with ultra-high frequency (262.144 kHz) which is claimed to be accurate to +/− 10 seconds a year and has a smooth sweeping second hand rather than one that jumps each second.


title: Watch

text: Radio time signal watches are a type of electronic quartz watch that synchronizes (time transfers) its time with an external time source such as in atomic clocks, time signals from GPS navigation satellites, the German DCF77 signal in Europe, WWVB in the US, and others. Movements of this type may - among others - synchronize the time of day and the date, the leap-year status and the state of daylight saving time (on or off). However, other than the radio receiver, these watches are normal quartz watches in all other aspects.


title: Watch

text: Electronic watches require electricity as a power source, and some mechanical movements and hybrid electronic-mechanical movements also require electricity. Usually, the electricity is provided by a replaceable battery. The first use of electrical power in watches was as a substitute for the mainspring, to remove the need for winding. The first electrically powered watch, the Hamilton Electric 500, was released in 1957 by the Hamilton Watch Company of Lancaster, Pennsylvania.


title: Watch

text: Watch batteries (strictly speaking cells, as a battery is composed of multiple cells) are specially designed for their purpose. They are very small and provide tiny amounts of power continuously for very long periods (several years or more). In most cases, replacing the battery requires a trip to a watch-repair shop or watch dealer; this is especially true for watches that are water-resistant, as special tools and procedures are required for the watch to remain water-resistant after battery replacement. Silver-oxide and lithium batteries are popular today; mercury batteries, formerly quite common, are no longer used, for environmental reasons. Cheap batteries may be alkaline, of the same size as silver-oxide cells but providing shorter life. Rechargeable batteries are used in some solar-powered watches.


title: Watch

text: Some electronic watches are powered by the movement of the wearer. For instance, Seiko's kinetic-powered quartz watches use the motion of the wearer's arm: turning a rotating weight which causes a tiny generator to supply power to charge a rechargeable battery that runs the watch. The concept is similar to that of self-winding spring movements, except that electrical power is generated instead of mechanical spring tension.


title: Watch

text: Solar powered watches are powered by light. A photovoltaic cell on the face (dial) of the watch converts light to electricity, which is used to charge a rechargeable battery or capacitor. The movement of the watch draws its power from the rechargeable battery or capacitor. As long as the watch is regularly exposed to fairly strong light (such as sunlight), it never needs a battery replacement. Some models need only a few minutes of sunlight to provide weeks of energy (as in the Citizen Eco-Drive). Some of the early solar watches of the 1970s had innovative and unique designs to accommodate the array of solar cells needed to power them (Synchronar, Nepro, Sicura, and some models by Cristalonic, Alba, Seiko, and Citizen). As the decades progressed and the efficiency of the solar cells increased while the power requirements of the movement and display decreased, solar watches began to be designed to look like other conventional watches.


title: Watch

text: A rarely used power source is the temperature difference between the wearer's arm and the surrounding environment (as applied in the Citizen Eco-Drive Thermo).


title: Watch

text: Traditionally, watches have displayed the time in analog form, with a numbered dial upon which are mounted at least a rotating hour hand and a longer, rotating minute hand. Many watches also incorporate a third hand that shows the current second of the current minute. In quartz watches this second hand typically snaps to the next marker every second. In mechanical watches, the second hand may appear to glide continuously, though in fact it merely moves in smaller steps, typically one-fifth to one-tenth of a second, corresponding to the beat (half period) of the balance wheel. With a "duplex" escapement, the hand advances every two beats (full period) of the balance wheel, typically -second; this happens every four beats (two periods, 1 second), with a "double duplex" escapement. A truly gliding second hand is achieved with the "tri-synchro regulator" of Spring Drive watches. All three hands are normally mechanical, physically rotating on the dial, although a few watches have been produced with "hands" simulated by a liquid-crystal display.


title: Watch

text: Analog display of the time is nearly universal in watches sold as jewelry or collectibles, and in these watches, the range of different styles of hands, numbers, and other aspects of the analog dial is very broad. In watches sold for timekeeping, analog display remains very popular, as many people find it easier to read than digital display; but in timekeeping watches the emphasis is on clarity and accurate reading of the time under all conditions (clearly marked digits, easily visible hands, large watch faces, etc.). They are specifically designed for the left wrist with the stem (the knob used for changing the time) on the right side of the watch; this makes it easy to change the time without removing the watch from the wrist. This is the case if one is right-handed and the watch is worn on the left wrist (as is traditionally done). If one is left-handed and wears the watch on the right wrist, one has to remove the watch from the wrist to reset the time or to wind the watch.


title: Watch

text: Analog watches, as well as clocks, are often marketed showing a display time of approximately 1:50 or 10:10. This creates a visually pleasing smile-like face on the upper half of the watch, in addition to enclosing the manufacturer's name. Digital displays often show a time of 12:08, where the increase in the number of active segments or pixels gives a positive feeling.


title: Watch

text: Tissot, a Swiss luxury watchmaker, makes the Silen-T wristwatch with a touch-sensitive face that vibrates to help the user to tell time eyes-free. The bezel of the watch features raised bumps at each hour mark; after briefly touching the face of the watch, the wearer runs a finger around the bezel clockwise. When the finger reaches the bump indicating the hour, the watch vibrates continuously, and when the finger reaches the bump indicating the minute, the watch vibrates intermittently.


title: Watch

text: Eone Timepieces, a Washington D.C.-based company, launched its first tactile analog wristwatch, the "Bradley," on 11 July 2013 on the "Kickstarter" website. The device is primarily designed for sight-impaired users, who can use the watch's two ball bearings to determine the time, but it is also suitable for general use. The watch features raised marks at each hour and two moving, magnetically attached ball bearings. One ball bearing, on the edge of the watch, indicates the hour, while the other, on the face, indicates the minute.


title: Watch

text: A digital display shows the time as a number, e.g., 12:08 instead of a shorthand pointing towards the number 12 and a long hand 8/60 of the way around the dial. The digits are usually shown as a seven-segment display.


title: Watch

text: The first digital pocket watches appeared in the late 19th century. In the 1920s, the first digital mechanical wristwatches appeared.


title: Watch

text: The first digital "electronic" watch, a Pulsar LED prototype in 1970, was developed jointly by Hamilton Watch Company and Electro-Data, founded by George H. Thiess. John Bergey, the head of Hamilton's Pulsar division, said that he was inspired to make a digital timepiece by the then-futuristic digital clock that Hamilton themselves made for the 1968 science fiction film "". On 4 April 1972, the Pulsar was finally ready, made in an 18-carat gold case and sold for $2,100. It had a red light-emitting diode (LED) display.


title: Watch

text: Digital LED watches were very expensive and out of reach to the common consumer until 1975, when Texas Instruments started to mass-produce LED watches inside a plastic case. These watches, which first retailed for only $20, reduced to $10 in 1976, saw Pulsar lose $6 million and the Pulsar brand sold to Seiko.


title: Watch

text: An early LED watch that was rather problematic was The Black Watch made and sold by British company Sinclair Radionics in 1975. This was only sold for a few years, as production problems and returned (faulty) product forced the company to cease production.


title: Watch

text: Most watches with LED displays required that the user press a button to see the time displayed for a few seconds because LEDs used so much power that they could not be kept operating continuously. Usually, the LED display color would be red. Watches with LED displays were popular for a few years, but soon the LED displays were superseded by liquid crystal displays (LCDs), which used less battery power and were much more convenient in use, with the display always visible and eliminating the need to push a button before seeing the time. Only in darkness would a button needed to be pressed to illuminate the display with a tiny light bulb, later illuminating LEDs and electroluminescent backlights.


title: Watch

text: The first LCD watch with a six-digit LCD was the 1973 Seiko 06LC, although various forms of early LCD watches with a four-digit display were marketed as early as 1972 including the 1972 Gruen Teletime LCD Watch, and the Cox Electronic Systems Quarza. The Quarza, introduced in 1972 had the first Field Effect LCD readable in direct sunlight and produced by the International Liquid Crystal Corporation of Cleveland, Ohio. In Switzerland, Ebauches Electronic SA presented a prototype eight-digit LCD wristwatch showing time and date at the MUBA Fair, Basle, in March 1973, using a twisted nematic LCD manufactured by Brown, Boveri & Cie, Switzerland, which became the supplier of LCDs to Casio for the "CASIOTRON" watch in 1974.


title: Watch

text: A problem with LCDs is that they use polarized light. If, for example, the user is wearing polarized sunglasses, the watch may be difficult to read because the plane of polarization of the display is roughly perpendicular to that of the glasses. If the light that illuminates the display is polarized, for example if it comes from a blue sky, the display may be difficult or impossible to read.


title: Watch

text: From the 1980s onward, digital watch technology vastly improved. In 1982, Seiko produced the Seiko TV Watch that had a television screen built-in, and Casio produced a digital watch with a thermometer (the TS-1000) as well as another that could translate 1,500 Japanese words into English. In 1985, Casio produced the CFX-400 scientific calculator watch. In 1987, Casio produced a watch that could dial telephone numbers (the DBA-800) and Citizen introduced one that would react to voice. In 1995, Timex released a watch that allowed the wearer to download and store data from a computer to their wrist. Some watches, such as the Timex Datalink USB, feature dot matrix displays. Since their apex during the late 1980s to mid-1990s high technology fad, digital watches have mostly become simpler, less expensive timepieces with little variety between models.


title: Watch

text: Many watches have displays that are illuminated, so they can be used in darkness. Various methods have been used to achieve this.


title: Watch

text: Mechanical watches often have luminous paint on their hands and hour marks. In the mid-20th century, radioactive material was often incorporated in the paint, so it would continue to glow without any exposure to light. Radium was often used but produced small amounts of radiation outside the watch that might have been hazardous. Tritium was used as a replacement, since the radiation it produces has such low energy that it cannot penetrate a watch glass. However, tritium is expensive - it has to be made in a nuclear reactor - and it has a half-life of only about 12 years so the paint remains luminous for only a few years. Nowadays, tritium is used in specialized watches, e.g., for military purposes (see Tritium illumination). For other purposes, luminous paint is sometimes used on analog displays, but no radioactive material is contained in it. This means that the display glows soon after being exposed to light and quickly fades.


title: Watch

text: Watches that incorporate batteries often have the electric illumination of their displays. However, lights consume far more power than electronic watch movements. To conserve the battery, the light is activated only when the user presses a button. Usually, the light remains lit for a few seconds after the button is released, which allows the user to move the hand out of the way.


title: Watch

text: In some early digital watches, LED displays were used, which could be read as easily in darkness as in daylight. The user had to press a button to light up the LEDs, which meant that the watch could not be read without the button being pressed, even in full daylight.


title: Watch

text: In some types of watches, small incandescent lamps or LEDs illuminate the display, which is not intrinsically luminous. These tend to produce very non-uniform illumination.


title: Watch

text: Other watches use electroluminescent material to produce uniform illumination of the background of the display, against which the hands or digits can be seen.


title: Watch

text: Talking watches are available, intended for the blind or visually impaired. They speak the time out loud at the press of a button. This has the disadvantage of disturbing others nearby or at least alerting the non-deaf that the wearer is checking the time. Tactile watches are preferred to avoid this awkwardness, but talking watches are preferred for those who are not confident in their ability to read a tactile watch reliably.


title: Watch

text: Wristwatches with analog displays generally have a small knob, called the crown, that can be used to adjust the time and, in mechanical watches, wind the spring. Almost always, the crown is located on the right-hand side of the watch so it can be worn of the left wrist for a right-handed individual. This makes it inconvenient to use if the watch is being worn on the right wrist. Some manufacturers offer "left-hand drive," aka "destro," configured watches which move the crown to the left side making wearing the watch easier for left-handed individuals.


title: Watch

text: A rarer configuration is the bullhead watch. Bullhead watches are generally, but not exclusively, chronographs. The configuration moves the crown and chronograph pushers to the top of the watch. Bullheads are commonly wristwatch chronographs that are intended to be used as stopwatches off the wrist. Examples are the Citizen Bullhead Change Timer and the Omega Seamaster Bullhead.


title: Watch

text: Digital watches generally have push-buttons that can be used to make adjustments. These are usually equally easy to use on either wrist.


title: Watch

text: 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 alarms. Other elaborate and more expensive watches, both pocket and wrist models, also incorporate striking mechanisms or 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 timepieces. This feature is available on most digital watches.


title: Watch

text: 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. 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 direction of Mecca and have alarms that can be set for all daily prayer requirements. Among watch enthusiasts, complicated watches are especially collectible. Some watches include a second 12-hour or 24-hour display for UTC or GMT.


title: Watch

text: 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.


title: Watch

text: Many computerized wristwatches have been developed, but none have had long-term sales success, because they have awkward user interfaces due to the tiny screens and buttons, and short battery life. As miniaturized electronics became cheaper, watches have been developed containing calculators, tonometers, barometers, altimeters, a compass using both hands to show the N/S direction, video games, digital cameras, keydrives, GPS receivers and cellular phones. A few 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).


title: Watch

text: Electronic sports watches, combining timekeeping with GPS and/or activity tracking, address the general fitness market and have the potential for commercial success (Garmin Forerunner, Garmin Vivofit, Epson, announced model of Swatch Touch series).


title: Watch

text: Braille watches 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.


title: Watch

text: Wristwatches and antique pocket watches are often appreciated as jewelry or as collectible works of art rather than just as timepieces. 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.


title: Watch

text: Traditionally, dress watches appropriate for informal (business), semi-formal, and formal attire are gold, thin, simple, and plain, but increasingly rugged, complicated, or sports watches are considered by some to be acceptable for such attire. Some dress watches have a cabochon on the crown or faceted gemstones on the face, bezel, or bracelet. Some are made entirely of faceted sapphire (corundum).


title: Watch

text: Many fashions and department stores offer a variety of less-expensive, trendy, "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.


title: Watch

text: Trade in counterfeit watches, which mimic expensive brand-name watches, constitutes an estimated market per year.


title: Watch

text: The zero-gravity environment and other extreme conditions encountered by astronauts in space require the use of specially tested watches.


title: Watch

text: The first-ever watch to be sent into space was a Russian "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.


title: Watch

text: On 12 April 1961, Gagarin wore a Shturmanskie (a transliteration of which actually means "navigator's") wristwatch during his historic first flight into space. The Shturmanskie was manufactured at the First Moscow Factory. Since 1964, the watches of the First Moscow Factory have been marked by the trademark "," transliterated as "POLJOT," which means "flight" in Russian and is a tribute to the many space trips its watches have accomplished. In the late 1970s, Poljot launched a new chrono movement, the 3133. With a 23 jewel movement and manual winding (43 hours), it was a modified Russian version of the Swiss Valjoux 7734 of the early 1970s. Poljot 3133 were taken into space by astronauts from Russia, France, Germany and Ukraine. On the arm of Valeriy Polyakov, a Poljot 3133 chronograph movement-based watch set a space record for the longest space flight in history.


title: Watch

text: 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. 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 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.


title: Watch

text: Since 1994 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 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.


title: Watch

text: Watch construction may be water-resistant. These watches are sometimes called diving watches when they are suitable for scuba diving or saturation diving. The International Organization for Standardization (ISO) issued a standard for water-resistant watches which also prohibits the term "waterproof" to be used with watches, which many countries have adopted. In the United States, advertising a watch as waterproof has been illegal since 1968, per Federal Trade Commission regulations regarding the "misrepresentation of protective features."


title: Watch

text: Water-resistance is achieved by the gaskets 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.


title: Watch

text: 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.


title: Watch

text: 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 ISO 6425 requirements have to be met.


title: Watch

text: Watches are classified by their degree of water resistance, which roughly translates to the following (1 metre = 3.281 feet):


title: Watch

text: Some watches use 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 atmospheres (atm), which are roughly equivalent to bar.


title: Watch

text: 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.


title: Younger (TV series)

text: Younger is an American comedy-drama television series created and produced by Darren Star. It is based on the 2005 novel of the same title by Pamela Redmond Satran. The single-camera series premiered on TV Land on March 31, 2015, and has since received generally positive reviews from critics. Ahead of the fifth season's premiere, it was renewed for a sixth season, which premiered on June 12, 2019. In July 2019, TV Land renewed the series for a seventh and final season, making it the longest running original series in the network's history.


title: Younger (TV series)

text: Sutton Foster stars as Liza Miller, a 40-year-old divorcee who has to manage her career in a publishing company having faked her identity as a younger woman to get her job, while her romantic and professional lives are measured against up-and-comings. Hilary Duff, Debi Mazar, Miriam Shor, and Nico Tortorella co-star in major supporting roles in the first season, with Molly Bernard and Peter Hermann in recurring roles. For the second season, Bernard and Hermann were promoted to series regulars. Charles Michael Davis had a recurring role in the fourth season and was promoted to the main cast for the fifth season. However, for the seventh and final season, Shor and Davis were downgraded to recurring guest stars, as they each appeared in only one episode of the season.


title: Younger (TV series)

text: The series moved from TV Land to Paramount+ and Hulu for its seventh and final season, which premiered on April 15, 2021, and concluded on June 10, 2021. The seventh season was later aired on TV Land.


title: Younger (TV series)

text: Set in New York City, the story follows the personal and professional life of Liza Miller, who is now single and all alone in her 40s following a contentious divorce from her gambling-addicted husband, and learning that her only daughter decided to live in India full time. After a run in with a 26 year old tattoo artist, Josh, who believes he and Liza are the same age, she devises a plan to pass herself off as a 20-something in order to re-enter the world of publishing, which has gotten rather ageist over the years, and becomes assistant to the head of Empirical Press Marketing Chief Diana Trout while befriending Kelsey Peters, her coworker. She finds it hard to live the best of both worlds as she has to balance her old middle age life with her renewed 20s.


title: Younger (TV series)

text: The series is based on the Pamela Redmond Satran's novel of the same name. In October 2013, TV Land ordered the pilot from creator and executive producer Darren Star. Patricia Field, who worked with Star on "Sex and the City", is a costume consultant on the production. The pilot was picked up to series in April 2014, with a 12-episode order. On April 21, 2015, "Younger" was renewed for a second season of 12 episodes, which premiered on January 13, 2016. Ahead of the fifth season's premiere, it was renewed for a sixth season, which premiered on June 12, 2019. On July 24, 2019, TV Land renewed the series for a seventh season, making it the longest running original series in the network's history. The series moved from TV Land to Paramount+ and Hulu with the seventh and final season which premiered on April 15, 2021 with the first 4 episodes available immediately and the rest debuting on a weekly basis.


title: Younger (TV series)

text: Sutton Foster was cast in the lead role of Liza Miller in December 2013. Hilary Duff and Miriam Shor joined the main cast in the following month. Debi Mazar was cast in February 2014. After a recurring role in the first season, Molly Bernard was added to the main cast from the second season onward. In February 2018, it was announced that Charles Michael Davis had been promoted to series regular, after appearing in a recurring capacity in the fourth season. On March 14, 2018, it was announced that Christian Borle would appear in the fifth season in a guest starring role playing the journalist Don Ridley in two episodes. On May 4, 2018, it was confirmed that Laura Benanti would appear in the fifth season, playing a self-made billionaire named Quinn. On March 17, 2021, it was announced that Miriam Shor and Charles Michael Davis have been demoted to recurring guest stars for the seventh and final season. In April 2021, Janeane Garofalo was cast in a recurring role for the final season.


title: Younger (TV series)

text: The series aired on NickMom from September 16 to September 27 2015, On September 5, 2018, it was announced that the series would be moved to Paramount Network from the sixth season onward; however, it was announced on April 3, 2019 that the series would stay on TV Land. Broadcasters carrying "Younger" include M3, E!, and CTV 2 in Canada; and Sony and Comedy Central in the United Kingdom.


title: Younger (TV series)

text: In June 2018, during the opening night screening at the annual ATX Television Festival in Austin, Texas, a first look at the second episode of the fifth season was showcased, whilst a panel discussion with Darren Star and cast members took place. That same month, the book "Marriage Vacation," mentioned in the series, was launched in real life by Simon & Schuster. In June 2019, the sixth-season premiere was also screened at the ATX Television Festival, followed by an interview with cast member Debi Mazar and writers Sarah Choi and Joe Murphy.


title: Younger (TV series)

text: "Younger" has received critical acclaim. Rotten Tomatoes gives the first season an approval rating of 97% based on 37 reviews, and an average rating of 7.6/10. The site's critical consensus reads, "Darren Star's witty writing and Sutton Foster's charisma help elevate "Younger" above some of TV Land's previous sitcoms." Metacritic gives the first season a weighted average score of 75 out of 100, based on 20 critics, indicating "generally favorable reviews".


title: Younger (TV series)

text: On Rotten Tomatoes, the second season has an approval rating of 100% based on 8 reviews, and an average rating of 7.1/10. Metacritic gave the season a score of 74 out of 100, based on reviews from 4 critics, indicating "generally favorable reviews".


title: Younger (TV series)

text: Brian Lowry of "Variety" gave the series a mostly positive review, describing it as "not perfect but highly watchable" and pointing out that "inevitably, there are stereotypical aspects on both sides of the age gap—from the flakiness of Kelsey's contemporaries to Diana too often coming across as a bitter scold—but the series seldom pitches so far across those lines as to be unable to find its way back."


title: Younger (TV series)

text: On the "New York" magazine website Vulture.com, Margaret Lyons gave a mostly positive review, describing "a sweetness to the series, an almost admiration for the various crummy behaviors [of the characters]." She went on to say that she wished the show "had a longer first season not just because I liked it, but more because it's featherweight, and as its current run stands, might have been better off as a feature-length rom-com." Megan Garber reviewed the show for "The Atlantic" saying, ""Younger", a fairy tale fit for basic cable, is a treacly confection of a show: witty but not wise, delightful but not deep. And yet—like its creator Darren Star’s previous exploration of age and sexuality and identity in a tumultuous time, "Sex and the City"—it offers, almost in spite of itself, deep insights into the culture of the moment."


title: Younger (TV series)

text: Tom Conroy of "Media Life Magazine" criticized the show mainly for portraying Sutton Foster's character Liza with "early-middle-age cluelessness", featuring "particularly silly" publishing-industry details and presenting "a relationship between an educated 40-year-old mother and a 26-year-old college dropout" that, in his belief, "has nowhere to go."


title: Younger (TV series)

text: But Jonathan Alexander writes in the Los Angeles Review of Books that ""Younger" works in part because it plays to both millennials, who are often portrayed as hip and hardworking, creative and generous, as well as to late Gen-Xers who are facing a corporate and consumer world that's seemingly forgotten them in its drive to cater to the needs, tastes, and interests of a younger (and numerically larger) generation."


title: Younger (TV series)

text: Darcie Wilder of "Vice" wrote in her review: ""Younger" is unexpectedly addictive, nothing short of extremely soothing and pleasurable to watch. It's a bedtime story that's supposed to lull but is too engaging to ever actually let you doze off. Usually when I binge, there's a hard out when I finally get caught up to real time, entering the headspace of its regular audience and eventually losing interest—but that hasn't happened with "Younger", not yet."


title: Younger (TV series)

text: The seventh and final season of "Younger" had good reviews from critics and mixed reviews from fans. Nicole Galluci of "Mashable" wrote in a review "Ultimately, the episodes are engaging as ever, and though it's rare with final seasons, I find myself struggling to squash the belief that this show still has so much left to give." Fan reacted to the final season with "mixed feelings," according to multiple reports.


title: Younger (TV series)

text: It was reported in May 2020 that ViacomCBS and Darren Star have partnered to develop a spin-off series which would revolve around Kelsey Peters, with Hilary Duff starring. However, on June 10, 2021, following the series’ conclusion, it has been revealed that the spin-off is no longer in the works, due to Duff being cast on the "How I Met Your Mother" spin-off, "How I Met Your Father". According to creator Darren Star, he stated that the "Kelsey" spin-off has been resolved after the series finale, regardless of any notion of one. Star also stated that "it was always going to end with Kelsey doing her own thing, alone, heading to Los Angeles".


title: Younger (TV series)

text: South Korean television network JTBC plans to broadcast the Korean adaptation of "Younger". It will be directed by Kim Seong-yoon as his first project under JTBC after leaving his longtime home network, KBS.


title: Younger (TV series)

text: The series is being adapted in China by Endemol Shine China and Huace Group. It is being remade as a 40-part series in Mandarin with episodes of 45 minutes.


title: Variant Creutzfeldt–Jakob disease

text: Variant Creutzfeldt–Jakob disease (vCJD), commonly referred to as "mad cow disease" or "human mad cow disease" to distinguish it from its BSE counterpart, is a fatal type of brain disease within the transmissible spongiform encephalopathy family. Initial symptoms include psychiatric problems, behavioral changes, and painful sensations. In the later stages of the illness, patients may exhibit poor coordination, dementia and involuntary movements. The length of time between exposure and the development of symptoms is unclear, but is believed to be years to decades. Average life expectancy following the onset of symptoms is 13 months.


title: Variant Creutzfeldt–Jakob disease

text: It is caused by prions, which are misfolded proteins. Spread is believed to be primarily due to eating bovine spongiform encephalopathy (BSE)-infected beef. Infection is also believed to require a specific genetic susceptibility. Spread may potentially also occur via blood products or contaminated surgical equipment. Diagnosis is by brain biopsy but can be suspected based on certain other criteria. It is different from typical Creutzfeldt–Jakob disease, though both are due to prions.


title: Variant Creutzfeldt–Jakob disease

text: Treatment for vCJD involves supportive care. As of 2020, 178 cases of vCJD have been recorded in the United Kingdom, due to a 1990s outbreak, and 50 cases in the rest of the world. The disease has become less common since 2000. The typical age of onset is less than 30 years old. It was first identified in 1996 by the National CJD Surveillance Unit in Edinburgh, Scotland.


title: Variant Creutzfeldt–Jakob disease

text: Initial symptoms include psychiatric problems, behavioral changes, and painful sensations. In the later stages of the illness, patients may exhibit poor coordination, dementia and involuntary movements. The length of time between exposure and the development of symptoms is unclear, but is believed to be years. Average life expectancy following the onset of symptoms is 13 months.


title: Variant Creutzfeldt–Jakob disease

text: In the UK, the primary cause of vCJD has been eating beef tainted with bovine spongiform encephalopathy. A 2012 study by the Health Protection Agency showed that around 1 in 2,000 people in the UK show signs of abnormal prion accumulation.


title: Variant Creutzfeldt–Jakob disease

text: Jonathan Quick, instructor of medicine at the Department of Global Health and Social Medicine at Harvard Medical School, stated that bovine spongiform encephalopathy or BSE is the first man-made epidemic, or "Frankenstein" disease, because a human decision to feed meat and bone meal to previously herbivorous cattle (as a source of protein) caused what was previously an animal pathogen to enter into the human food chain, and from there to begin causing humans to contract vCJD.


title: Variant Creutzfeldt–Jakob disease

text: As of 2018, evidence suggests that while there may be prions in the blood of individuals with vCJD, but this is not the case in individuals with sporadic CJD.


title: Variant Creutzfeldt–Jakob disease

text: In 2004, a report showed that vCJD can be transmitted by blood transfusions. The finding alarmed healthcare officials because a large epidemic of the disease could result in the near future. A blood test for vCJD infection is possible but is not yet available for screening blood donations. Significant restrictions exist to protect the blood supply. The UK government banned anyone who had received a blood transfusion since January 1980 from donating blood. Since 1999 there has been a ban in the UK for using UK blood to manufacture fractional products such as albumin.


title: Variant Creutzfeldt–Jakob disease

text: Whilst these restrictions may go some way to preventing a self-sustaining epidemic of secondary infections, the number of infected blood donations is unknown and could be considerable. In June 2013 the government was warned that deaths, then at 176, could rise five-fold through blood transfusions.


title: Variant Creutzfeldt–Jakob disease

text: On 28 May 2002, the United States Food and Drug Administration instituted a policy that excludes from blood donation anyone having spent at least six months in certain European countries (or three months in the United Kingdom) from 1980 to 1996. Given the large number of U.S. military personnel and their dependents residing in Europe, it was expected that over 7% of donors would be deferred due to the policy. Later changes to this policy have relaxed the restriction to a cumulative total of five years or more of civilian travel in European countries (six months or more if military). The three-month restriction on travel to the UK, however, has not been changed.


title: Variant Creutzfeldt–Jakob disease

text: In New Zealand, the New Zealand Blood Service (NZBS) in 2000 introduced measures to preclude permanently donors having resided in the United Kingdom (including the Isle of Man and the Channel Islands) for a total of six months or more between January 1980 and December 1996. The measure resulted in ten percent of New Zealand's active blood donors at the time becoming ineligible to donate blood. In 2003, the NZBS further extended restrictions to permanently preclude donors having received a blood transfusion in the United Kingdom since January 1980, and in April 2006, restrictions were further extended to include the Republic of Ireland and France.


title: Variant Creutzfeldt–Jakob disease

text: Similar regulations are in place where anyone having spent more than six months for Germany or one year for France living in the UK between January 1980 and December 1996 is permanently banned from donating blood.


title: Variant Creutzfeldt–Jakob disease

text: In Canada, individuals are not eligible to donate blood or plasma if they have spent a cumulative total of three months or more in the UK, or France from 1 January 1980 to December 31, 1996. They are also ineligible if they have spent a cumulative total of five years or more in the Republic of Ireland since January 1, 1980 through 31 December 2001 or spent a cumulative total of six months or more in Saudi Arabia from January 1, 1980, through December 31, 1996 or if they have had a blood transfusion in the UK, France or Western Europe since 1980.


title: Variant Creutzfeldt–Jakob disease

text: In Poland, anyone having spent cumulatively six months or longer between 1 January 1980 and 31 December 1996 in the UK, Ireland, or France is permanently barred from donating.


title: Variant Creutzfeldt–Jakob disease

text: In France, anyone having lived or stayed in the United Kingdom a total of over one year between 1 January 1980 and 31 December 1996 is permanently barred from donating.


title: Variant Creutzfeldt–Jakob disease

text: In the Czech Republic, anyone having spent more than six months in the UK or France between the years 1980 and 1996 or received transfusion in the UK after the year 1980 is not allowed to donate blood.


title: Variant Creutzfeldt–Jakob disease

text: In Finland, anyone having lived or stayed in the British Isles a total of over six months between 1 January 1980 and 31 December 1996 is permanently barred from donating.


title: Variant Creutzfeldt–Jakob disease

text: In the U.S., the FDA has banned import of any donor sperm, motivated by a risk of variant Creutzfeldt-Jakob disease, inhibiting the once popular import of Scandinavian sperm. Despite this, the scientific consensus is that the risk is negligible, as there is no evidence Creutzfeldt–Jakob is sexually transmitted.


title: Variant Creutzfeldt–Jakob disease

text: In France, the last two victims of variant Creutzfeldt-Jakob disease, who died in 2019 and 2021, were research technicians at the National Research Institute for Agriculture, Food and the Environment (INRAE). Emilie Jaumain, who died in 2019, at the age of 33, had been the victim of a work accident in 2010, during which she had pricked herself with a tool contaminated with infected brain. The efficacy of this route of contamination has been unambiguously demonstrated in primates. Pierrette C., who died in 2021, had been victim of the same type of work accident. After her diagnosis, a moratorium was initiated in all French laboratories on research activities on infectious prions. In March 2022, INRAE recognized the occupational cause of these two deaths. This raises serious questions about the safety of personnel in these laboratories. Indeed, inspections have noted serious failures in the protection of agents in the face of this deadly risk, and the long incubation period of this disease leads to fears of new cases in the future, hence great concern.


title: Variant Creutzfeldt–Jakob disease

text: Eating other types of brains such as those from squirrels is not recommended as one person contracted vCJD from eating the brain of a squirrel.


title: Variant Creutzfeldt–Jakob disease

text: Despite the consumption of contaminated beef in the UK being high, vCJD has infected a small number of people. One explanation for this can be found in the genetics of people with the disease. The human PRNP protein which is subverted in prion disease can occur with either methionine or valine at amino acid 129, without any apparent physiological difference. Of the overall Caucasian population, about 40% have two methionine-containing alleles, 10% have two valine-containing alleles, and the other 50% are heterozygous at this position. Only a single person with vCJD tested was found to be heterozygous; most of those affected had two copies of the methionine-containing form. It is not yet known whether those unaffected are actually immune or only have a longer incubation period until symptoms appear.


title: Variant Creutzfeldt–Jakob disease

text: Examination of brain tissue is required to confirm a diagnosis of variant CJD. The following confirmatory features should be present:


title: Variant Creutzfeldt–Jakob disease

text: vCJD is a separate condition from classic Creutzfeldt–Jakob disease (though both are caused by PrP prions). Both classic and variant CJD are subtypes of Creutzfeldt–Jakob disease. There are three main categories of CJD disease: sporadic CJD, hereditary CJD, and acquired CJD, with variant CJD being in the acquired group along with iatrogenic CJD. The classic form includes sporadic and hereditary forms. Sporadic CJD is the most common type.


title: Variant Creutzfeldt–Jakob disease

text: ICD-10 has no separate code for vCJD and such cases are reported under the Creutzfeldt–Jakob disease code (A81.0).