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24-hour display
A wristwatch has a 24-hour display if its hour hand completes one complete rotation around its own axis over the course of an entire day and its dial is calibrated from 1 to 24. This type of display is rarely seen because it takes time to get used to and is difficult to read. Some wristwatches also have two separate hour hands: one of them rotates around its own axis once every 12 hours; the other hour hand completes the same orbit in 24 hours.

Adjusting organ
The regulating organ of a mechanical watch is the balance wheel with its spiral.

The process of setting or adjusting a clock.

Adjustment (timing, setting)
Timing the movement of a clock consists of observing its daily rate at various positions and at various temperatures, then (if necessary) making fine adjustments to optimize its speed. The amount of labor invested in this task is directly proportional to the quality of the clock and its desired degree of accuracy, which, in turn, is directly proportional to its price. Accurate timing according to official procedure requires adjusting the movement in at least five positions and at three different temperatures (23.8 and 38 degrees Celsius).

One of the first additional features assigned to train clocks with mechanical gears, the first alarm mechanisms were realised as early as the 16th century. They emit an acoustic signal when a predetermined time arrives. Eterna first patented an alarm wristwatch in 1908. The most famous wristwatches with alarm clocks include the 'Cricket' by Vulcain (which premiered in 1947), the 'Memovox' by Jaeger-LeCoultre ( launched in 1951) and the 'Memomatic' by Omega (launched in 1969). The alarm time on the 'Memomatic' can be set to the exact minute.

Analog time display
The time is indicated by a pair of hands. The current time is indicated by the relative positions of the hour hand and minute hand. With very few exceptions, almost all high-quality wristwatches are equipped with analog time display. The digital electronic watches that dominated the market in the 70s have lost most of their importance.

Annual calendar
Wristwatch displaying the correct date for the one-year interval from 1 March of one year to 28 February of the following year.

Automatic strike
The astonishing work of a pocket watch or wristwatch is automatic if, unlike the astonishing work of a repeater watch, it functions completely without the need for manual intervention. Like a household clock, an automatic strike watch audibly announces the arrival of the hours (petite sonnerie) or both hours and quarters (grande sonnerie). In response to the push of a button, these elaborate mechanisms can also be activated to strike the hours, quarters and minutes.

Automatic winding
An additional mechanism that uses the wearer's arm movements as a source of energy to wind the mainspring of a mechanical watch. Abraham Louis Perrelet is credited with the invention of the self-winding portable watch. A self-taught watchmaker, Perrelet presented two different self-winding constructions in 1770: one was based on an oscillating mass; the other on an infinitely rotating rotor. Both were designed to make the winding key superfluous. Self-winding mechanisms on pocket watches could not function efficiently because these watches do not undergo sufficient movement, so the popularity of such mechanisms remained limited. Wristwatches, which are worn on one of the most active parts of the body, helped self-winding achieve a breakthrough. The beginning of this breakthrough is attributed to the Parisian watchmaker Léon Leroy in 1922. The first mass-produced wristwatches with automatic winding were designed by Englishman John Harwood, who patented a corresponding mechanism in 1924. Rolex debuted the first wristwatch with rotor (unidirectional) winding in 1931. Felsa, the ébauche manufacturer, introduced a bidirectionally wound rotor in 1942. Eterna's ball-winding rotor, which debuted in 1948, paved the way for the self-winding systems that followed in later years. After the 'quartz crisis' had subsided somewhat, the renaissance of self-winding wristwatches began in 1983. Rolex debuted the first rotor-wound (unidirectional) wristwatch in 1931. Felsa, the ébauche manufacturer, introduced a bidirectionally wound rotor in 1942. Eterna's ball-winding rotor, which debuted in 1948, blazed a trail for the self-winding systems that followed in later years. After the 'quartz crisis' had subsided somewhat, the renaissance of self-winding wristwatches began in 1983. Rolex debuted the first rotor-wound (unidirectional) wristwatch in 1931. Felsa, the ébauche manufacturer, introduced a bidirectionally wound rotor in 1942. Eterna's ball-winding rotor, which debuted in 1948, blazed a trail for the self-winding systems that followed in later years. After the 'quartz crisis' had subsided somewhat, the renaissance of self-winding wristwatches began in 1983.

A circular metal circle which, together with the balance spring, embodies the regulating organ of a mechanical watch. It has a decisive influence on the accuracy of the watch's rhythm. The balance can be defined as an 'oscillating wheel' in static equilibrium. Bimetal balances were still used until the 1940s to compensate for temperature variations on precision clocks. After the self-compensating 'nivarox' balance spring had matured to the point where it was ready for series production in 1933, bimetal balances gradually became less important. They were increasingly replaced by monometallic 'glucydur' balances made of beryllium bronze. In combination with a nivarox balance spring, the glucydur balance was an ideal regulating organ that lost none of its importance in the following decades.

Balance Spring
The balance spring can appropriately be described as the 'soul' of a mechanical watch. The inner end of this coil spring is attached to the balance staff; the outer end is connected by the balance spring pin to the balance cock. The elasticity of the spring ensures that the balance regularly oscillates back and forth. In combination with the moment of inertia of the balance rim, the active length of the balance spring determines the duration of each balance vibration. For this reason, most watches are equipped with an index that can be moved in infinitesimal increments to precisely alter the active length of the balance spring. Lengthening the active length causes the watch to run slower; shortening the active length causes the watch to run faster. The precision of mechanical watches also depends on the quality of the material and the shape of the balance spring. This spring is three to four times thinner than a human hair and weighs 2/1000 of a gram (0.002 g). Despite its extreme slenderness and feather-light weight, it is still able to withstand tensions equal to a weight of 600 grams. The thin coils of a spiral contract every year and expand more than 200 million times.

Balance spring compensation
The elasticity of hardened steel balance springs varies with temperature. This causes corresponding changes in the speed of a watch. To counteract this effect, precision watches are equipped with a bimetal balance spring. Balance springs were first marketed under the name 'nivarox' in 1933. Nivarox, an alloy composed of several metals, enables the balance spring to compensate for temperature variations. All of today's top-quality wristwatches use nivarox balance springs in combination with monometallic glucide balances.

Balance Spring Stud
A small piece of metal, pinned or (in modern movements) glued to the outer end of the balance spring. The balance spring stud is attached (usually pinned) to the spigot or balance plate lug.

A specially shaped metal part in which at least one pin of a movable part of a watch turns. A bridge is screwed at both ends onto a plate, where the opposite end of the pin(s) is inserted. Bridges (also called 'bars') are usually named after the rotating parts they support, e.g. the centre wheel bridge or barrel bridge.

The barrel consists of a toothed disc and a cylindrical box. This latter is usually closed by a lid. The barrel rotates freely on its arbor. The main spring is wound inside the barrel. The toothed disc of the barrel meshes with the first pinion of the train of a mechanical clock.

A hole drilled to accept a pin of a gear train. In fine wristwatches and pocket watches, as well as in clocks, friction is reduced by inserting bearing jewellery into the holes that accept the rapidly rotating pivots of wheels and pinions. Simpler watches make do with simple holes drilled in plates, bridges or taps. However, this simpler solution has the drawback that the pivot holes soon enlarge through abrasion, especially if there is insufficient lubrication. This drawback can be remedied by inserting bushings, usually made of brass or bronze.

A silvery white, malleable metal extracted from beryl. Alloys containing beryllium are characterised by their unique hardness, strength and elasticity. Beryllium bronze is used in watches, e.g. to make scales. See also glucydur.

A term that can have a variety of meanings in watchmaking. Strictly speaking, it means that the ring is snapped in the center of a watch case to hold the glass. Often, however, the same word is also used to describe a rotating (usually metal) ring affixed to the front of a watch case.

Bimetal balance
Before the invention of the balance spring, high-quality mechanical watches were generally equipped with bimetal balance scales. The rim, which is cut close to the arms, is made of two metals (steel and brass) that have different coefficients of expansion when exposed to temperature changes. Changes in the moment of inertia of the balance compensate for thermally induced changes in the length of a hardened steel balance spring.

Blue hands and vines
It has been a long tradition among watchmaking craftsmen to blue the surfaces of steel components. Blueing requires a great amount of sensitivity and experience. The parts to be burnished are placed in a small pan, which is then heated over fire. The surfaces of these parts acquire the desired color when their temperature rises to just under 300 degrees Celsius.

This alloy of copper and zinc is an important metal used in the manufacture of watches. Depending on the purpose for which it will eventually be used (such as for use as a plate), brass alloys may contain varying amounts of their constituent substances.

Breguet hands
A popular, very elegant and classic shape for watch hands. A circular hole is located at the terminal end (near the tip) of a Breguet hand.

Breguet Overcoil Balance Spring
The decisive contribution to the optimisation of the balance spring was made by Abraham-Louis Breguet. This talented watchmaker recognised the importance of the terminal curve for the concentric 'breathing' of the balance spring. He debuted a type of spring that would later be known as the 'Breguet overcoil' in 1795. The distinguishing feature of this type of spring is its raised outer coil. This apparently minor detail improves the concentric development and thus the precision of the balance. Starting around 1860, Edouard Philips studied balance springs and their various forms. His research, which he published in 1861, is still valid today. The tables and graphs developed by this French mathematics professor served as an indispensable basis for the formation of subsequent balance springs.

Bridge movement
The wheels of a clock movement are carried under individual bridges that are screwed to the bottom plate.

Technical term used to describe the additional regulating mechanism added to a complicated watch: for example, the mechanism of a chronograph, a repeater with percussion or a calendar. Depending on the construction, a cadrature may be integrated into the movement or mounted on a separate plate and additively connected to the main movement. The latter, the so-called 'modular' solution, is usually less expensive because its manufacturers can rely on a ready-made movement. Integrated constructions, e.g. for chronographs or repeaters, have to be developed individually. Almost all additional features are now available in modular form.

The size and shape of a movement and its parts. The name and/or number of a calibre allows the exact identification of the device, for example, when ordering spare parts. Until the 1970s, large ébauche manufacturers sometimes had more than 100 different calibres in their product range. This wide diversity no longer exists for gauges. Traditionally, a distinction is made between round gauges for open watches (Lépines), round gauges for spring watches (Savonnettes or hunters) and gauges of various shapes (e.g. baguette, tonneau, oval or rectangular gauges). Lépine calibres can be recognised by the fact that the staff bearing the seconds hand is located along an imaginary line extending from the winding stem. This differs from the situation in hunter watches, where the staff carrying the seconds hand axis, the centre of the watch and the winding stem form a 90° angle. If there is a small seconds dial, it is located at the '6'. Ready-made ébauches supplied by ébauche suppliers should be distinguished from so-called 'manufacturer' calibres. The latter are movements that manufacturers produce for their own use. Finally, one sometimes encounters the term 'reserved' calibres. This refers to ébauche that ébauche manufacturers develop and/or produce exclusively for individual customers. Other établisseures do not have access to these gauges. Ready-made ébauches supplied by ébauche suppliers should be distinguished from so-called 'manufacturer' calibres. The latter are movements that manufactures produce for their own use. Finally, one sometimes encounters the term 'reserved' calibres. This refers to ébauche manufacturers develop and/or produce exclusively for individual customers. Other établisseures do not have access to these calibres.

Calibre with baguette alarm
An elongated rectangular calibre very popular in the 1920s and early 1930s. The ratio between its proportions (length and width) must be at least 3: 1.

The French word 'calotte' means 'skullcap'. In watchmaker's jargon, it describes a steeply domed case or the domed front of a wristwatch case.

Unit of measurement used to express the fineness of gold. So-called 'fine gold' is almost 100% pure and is synonymous with '24-carat gold'. If, for example, the case of a wristwatch is made of 18-carat gold, the alloy contains 750 parts of gold for every 1,000 parts of alloy. The remaining quarter of the alloy consists of other metals (copper, brass, silver, etc.). Fourteen-carat gold has a fineness of 585 parts per 1,000. Eight-carat gold has a fineness of 333 parts per 1,000. The fineness of the alloy is shown on the watch case as a distinctive mark engraved in the metal.

The outer protective case of a watch. Cases are made in a wide range of different versions and a wide range of materials. A distinction is made between open cases (Lépine) and closed cases (Hunter) on pocket watches. Cases that are splash-proof or completely waterproof to various depths are often used on wristwatches. There are also a large number of different case shapes (round, square, oval, rectangular, tonneau) and materials (platinum, gold, silver, steel, titanium, aluminium, plastic, etc.).

Central seconds (sweep seconds)
A seconds hand whose axis is located in the center of the dial. On watches with central seconds, the shaft of the central wheel is hollowed out to provide space for the staff on which the seconds hand is attached perpendicularly. A distinction must be made between movements with direct central seconds and those with indirect central seconds. The former is within the energy flow of the gear train; the latter is outside the flow.

Central European Time. Germany and other central European countries established Central European Time on 1 April 1893. Central European Time is one hour ahead (+1) of World or Universal Time (also known as GMT or Greenwich Mean Time). GMT is defined as mean solar time at the Greenwich meridian (0° longitude).

There is no Italian equivalent for this technical term in French watchmaker's jargon. It indicates a series of unassembled components for a movement blank.

The word 'chronograph' (or the more etymologically accurate term 'chronoscope') describes a watch with an hour and minute hand, as well as a chronograph seconds hand (usually centrally axial or 'running'). The latter hand is connected to a special additional mechanism that starts, stops and returns the hand to its zero position, usually in response to the pressing of one or more pushers. The time display is not affected by the activity of this mechanism. Depending on the specific version, a chronograph may also be equipped with counters for counting the minutes and hours elapsed since the activation of the stop-time feature. By pressing the reset pusher, all chronograph hands (including those on the counters) return to their initial positions. Chronographs with two pushers have dominated the market since the 1930s. One of the two pushers starts and stops the chronograph hand; the other returns it to its zero position. Chronographs of this type make additive stopping possible, i.e. the chronograph hand can be repeatedly stopped and restarted from the position it was at the instant it was stopped. Depending on the frequency of the balance, a mechanical wrist chronograph can stop time with an accuracy of up to a tenth of a second.

A precision watch that has demonstrated the accuracy of its rate during a series of 15-day tests conducted at an official test site (e.g. at the COSC in Switzerland). To qualify as a chronometer, the average daily rate of the watch must not exceed -4 or +6 seconds in each of the following five positions: crown left, crown up, crown down, dial up and dial down. The average daily speed deviation may not exceed two seconds; the maximum speed deviation may not exceed five seconds. All candidate watches are tested at temperatures of 23.8 and 38 degrees Celsius. Only after passing the chronometer tests does a watch earn the right to bear the word 'chronometer' on the dial and be sold together with an official classification certificate.

Unlike chronographs, stopwatches do not display the ordinary time of day. In simply constructed chronometers, pressing a button stops the progress of the movement, thus also stopping the progress of the seconds hand.

A mechanical movement performs a very difficult task. Needless to say, a car, whose parts are in motion only a few hours a day, receives an oil change and maintenance at regular intervals. The parts of a watch, by comparison, are in motion 24 hours a day. Failure to maintain the watch regularly can result in damage to the delicate components of the watch's gear train. When a watch is delivered for maintenance, qualified watchmakers completely disassemble the movement, thoroughly check each part, and then reassemble the watch.

Cloisonne Enamel
Enamel that has been divided into polychrome compartments (so-called “ cloison”) by means of metal partitions that prevent the mixing of the liquefied material. Gold threads measuring 0.007 mm wide and about one mm high are folded into the desired shapes and attached to the dial to create a pattern. A specially trained craftsman known as “cloisonneur (e)” performs these tasks, the difficulty of which is inversely proportional to the size of the dial or pattern. After the threads are bent and fixed to create the finished pattern, each of the tiny cloison is filled with powdered enamel of the desired color. Up to five layers of this fine-grained material should be applied with a quill pen. After applying each layer, the workpiece must be baked in an oven. The bottom layer merges with the top layer to create a play of colors with many shades. The gold threads protrude above the plane of the last layer of enamel, so the cloisonneur (e) must sand them manually until they are flush with the surface of the enamel. This abrasion is followed by a final hand polishing.

Coaxial escapement
An escapement for mechanical watches invented by English master watchmaker George Daniels. Thanks to a thorough redesign of the impulse elements, the resulting friction, which cannot be completely eliminated, is greatly reduced, making it possible to do without lubricating oil. This, in turn, avoids the deleterious effects on the amplitude of the oscillating system that are caused by the viscosity of liquid lubricants. Maintenance intervals can be significantly lengthened. Unlike conventional escapements (pallet, escape wheel), the coaxial escapement consists of three components: an intermediate wheel, a coaxial wheel, and a pallet with three pallet jewels. As in a conventional anchor escapement, the roller table is attached to the balance wheel;unlike the roller table of an ordinary escapement (which has only one roller jewel), the roller table of a coaxial escapement also has an impulse pallet. The name "coaxial escapement" comes from the fact that a single rod serves as the common axis of the escape wheel and the large pinion of the escape wheel (with its wolf teeth, which mesh with the teeth of the intermediate wheel). With regard to the operation of the whole assembly, suffice it to say the following: when the balance turns clockwise, it receives a direct stimulus from the escape wheel to the pulse pallet of the roller wheel. Only when the scale turns counterclockwise do the actual pallets come into play. A small pulse is given by the escape wheel sprocket to the center pulse pallet on the pallets. After each impulse, the escape wheel is briefly stopped by the outer pallet jewel so that the scale can continue to swing freely in the same direction.

Coin Watch
A coin with an incorporated watch movement. The first coin watches were made in the 18th century. To create such watches, a coin is halved, then each half is emptied and an ultra-flat movement is sandwiched between the two halves of the coin.

Column-wheel chronograph
Without an intelligent steering mechanism, it would not be possible to start, stop and reset the seconds hand of a chronograph independently of the movement. Classic chronograph calibres rely on a rotating column wheel to govern these three features. Depending on the details of the movement construction, this relatively elaborate component can have five, six, seven, eight or even nine columns. Each time one of the chronograph features is activated, the column wheel advances clockwise along a precisely defined angle. If the end of a balance wheel stops on one of its columns, the latter holds the first in its raised position. If the balance wheel stops between two columns, a slight pressure from a spring keeps it in a depressed position.

Compensating balance
Temperature variations have a deleterious effect on the speed of a mechanical watch because they alter the elasticity of the steel balance springs. Rising temperatures cause a watch to lose speed; falling temperatures, on the other hand, increase its speed. More than 200 years ago, the English watchmaker John Arnold invented the bimetallic rim with slotted compensation, which partly compensated for the non-negligible errors that temperature variations caused in the steel balance. As the name explicitly states, this component consists of a bimetallic rim made of two joined metals (e.g. steel on the inside and brass on the outside). Brass has a higher coefficient of expansion than steel. When temperatures rise, brass expands more than steel so that the free ends of the slotted brass hoop shift position towards the rocker arm. This compensates for the elongation of the steel balance spring. When the temperature drops, the balance rim has the opposite effect. Compensating balances are more expensive to produce and more elaborate to assemble than normal balances, so they are only used in better quality watches. Cheaper movement balances lack this compensation capability, so the speed of cheaper movements is more drastically affected by changes in ambient temperature.

An additional mechanism in a mechanical watch. The most important complications include: automatic winding systems, equation-of-time displays, chronographs, as well as flybacks, perpetual calendar, repeater movements, automatic chimes (grande / petine sonnerie), tourbillons and alarms.

Contrôle Officiel Suisse des Chronomètres (Swiss Official Chronometer Testing Site). A Swiss agency with headquarters in La Chaux-de-Fonds and branches in Bienne, Geneva and Le Locle that conducts all official chronometer tests and issues the corresponding evaluation certificates. The acronym 'COSC' has been in use since 1973.

Counterfeiting of watches was already a serious problem long before the Far East became a destination for mass tourism. Abraham Louis Breguet (1747-1823) used a secret insignia in his attempt to protect himself from the unauthorised misuse of his name. Renowned watch companies exert rigorous efforts to combat counterfeiting, but the ongoing fight against imitators seems almost hopeless. Like the legendary Hydra, every counterfeit destroyed seems to generate two new ones. Modern fakes are more or less accurate copies of common watch models. They are mainly based on the easily recognisable appearance of the authentic watch and/or the insignia of its manufacturer. The quality of the imitation generally plays a subordinate role. The criminal energy is directed less at the buyer of the fake, who usually knows what he is getting for his typical small amount of money. The damage is suffered by almost all luxury brands. Certificates, invoices and cases no longer serve as a guarantee of authenticity because even these items are readily and frequently counterfeited.

A usually grooved pusher that can be turned to wind the mainspring, set the hands and/or adjust the date display. The crown was also sometimes used to govern the chronograph feature on older watches. On modern watertight watches, the crown may be screwed into the case frequently. A strong side blow to the crown can cause it to break, so case rims on modern sports wristwatches usually protrude slightly on either side of the crown to protect the crown from damage.

Crystal glass
Colorless glass. Glass was used as a material to protect watch dials until the 40s. The problem with glass crystals is that they tend to break. Even a slight blow against the crystal can shatter the fragile glass sheet.

Various types of crystals are used on wristwatches. Glass crystals are mainly found on the first wristwatches. These crystals are scratch-resistant, but very fragile and prone to shattering. From the 1940s onwards, glass crystals were increasingly replaced by artificial plastic crystals (Plexiglas). These are unbreakable, but prone to scratching. Mineral crystals have a hardness of 5 on the Mohs scale and are therefore significantly stronger than Plexiglas crystals. Today's high-quality wristwatches rely mainly on synthetic sapphire for their crystals. This material, which has a hardness of 9 on the Mohs scale, is extremely scratch-resistant, but can only be machined with special diamond tools.

Cylinder escapement
The cylinder escapement was invented by English watchmaker George Graham around 1726. This type of escapement is found in early wristwatches. If it is used in a brand newwristwatch, its presence suggests that this watch is simpler and less expensive. The cylinder escapement forgoes pallets as a connecting ring. Instead, the teeth of the escape wheel penetrate directly into a hollow cylinder, which simultaneously serves as a balance wheel. Because of the insufficiently accurate rate of movement based on this type of escapement, the cylinder escapement is no longer used in contemporary watches.

Date display
The date can be shown i.e. with one hand or digitally with numbers printed on a disk.. The date hand or disk rotates around its axis once every 31 days, advancing by an increment around midnight on each subsequent day. On a hand date display, the numbers 1 through 31 are printed on the dial, and the designated hand tip indicates the current date. Wristwatches with digital date display have a date disk affixed to the front of the movement. The number corresponding to the current date appears inside a small window cut into the dial. A magnifying glass integrated into the crystal improves its readability. A distinction should be made between "crawling" and "hopping"views. The first are gently and gradually advanced by the movement of the clock. The latter continuously absorbs energy from the movement during the course of the day and stores that energy in a spring, which releases its energy reserve right at midnight, making the display of the date of an increase jump forward. Daters may have a single ring, two disks, two concentrically arranged and numbered disks, or a circular and a cruciform disk. In the last variant, the circular disk bears the digits in the "one" column, and the cruciform disk carries the digits (and the blank for single-digit dates) in the "tens"column to indicate the date. These "big date" displays are larger and therefore more easily readable than smaller displays with only one window. which releases its energy reserve right at midnight, making the display of the date of an increase jump forward.

According to international agreement, the dateline almost coincides with the 180th meridian of longitude, which crosses the Pacific Ocean near New Zealand and the Fiji Islands. A westbound traveller crossing the dateline 'loses' a day and jumps forward to the day and date after tomorrow. An eastbound traveller crossing the data line 'gains' a day and repeats the same day and date a second time. This procedure compensates for the differences in dates and days of the week that occur during a circumnavigation.

Digital time display
Representation of time by numbers. Digital indicators for hours, minutes, seconds and / or date were already in use before the invention of quartz watches. Digital hour displays on quartz wristwatches initially used light-emitting diodes (LEDs), but these used too much electricity, so they were soon replaced by liquid crystal diodes (LCDs).

A display, e.g. of time, date, day of the week, month, equation of time, power reserve, time in a second time zone, etc.

Diving watches
A wristwatch worn while swimming or scuba diving must have a waterproof case up to 100 meters; according to German industry standard No. 8306, a diving watch must meet other criteria as well. In addition to its watertightness and good legibility, it must also have a mechanism (such as a bezel that rotates in one direction) that allows to preset the duration of a dive. Readability is also strictly defined. The day time, preset dive time, and watch functions must be clearly readable from a distance of 25 centimeters in complete darkness. Professional diving watches must be water resistant to at least 200 meters. In addition, their waterproofness should be tested at annual intervals. A dive watch that meets all these criteria can carry the DIN (German industrial standard) mark. For their own safety, divers should have the waterproofness of their watches tested twice a year.

Doublé (flat, plating)
The French verb "duplicator" means "to double." At first glance, watches with doubled cases appear to be more precious than they actually are. A usually non-precious substrate is plated with a more or less thin layer of precious metal, for example, by pressing the precious metal layer onto the substructure in a hydraulic press. If the precious metal is gold, the result is called "rolled gold plating." In addition to gold, other precious metals such as silver or platinum can also be employed as plating. The thickness of precious metal plating is measured in microns (thousandths of a millimeter). Twenty microns means that the precious metal layer is 20/1000 or 2/100ths of a millimeter thick. A disadvantage associated with plated wristwatches is that the precious metal coating wears off gradually. The rate at which this occurs depends on how often the watch is worn and the amount of sweat it is exposed to. The backs of plated watches are often made of sturdy stainless steel.

Double-faced clock
A watch with one face on the front and another on the back. Double-faced pocket watches are much more common than double-faced wristwatches. Modern double-faced wristwatches are available, for example, from Jaeger-LeCoultre "Reverso Duo-Face"and Patek Philippe "Sky Moon Tourbillon".

Dual movement
A watch with two completely separate movements (hand-wound, automatic or quartz) that can be used, for example, to show the time in two different time zones. The main problem associated with wristwatches that have dual movements, and particularly mechanical models, is that the two movements may deviate from synchronisation due to differences in their speeds.

Ébauche (Empty movement, incomplete movement)
French term for 'sketch'. In watchmaker's jargon, the rough movement of a watch is described as an 'ébauche'. A functional movement consists of a vacuum movement, an escapement, a balance wheel in the shape of a circle and its spiral balance spring, a mainspring, a dial and hands. An ébauche is a complete movement (plates, bridges, gear train, steel components) without an escapement, balance, hairspring, mainspring, dial and hands. Depending on the recipient's specifications, ébauches are currently available with or without pressed jewels. The French word chablon, for which there is no English equivalent, is sometimes used in the context of movement blanks. A chablon is a set of unassembled components for an entire calibre or for various parts of a calibre. Movement blanks are produced by specialised companies (e.g. Eta, Nouvelle Lémania, Frédéric Piguet).

Eight-day movement
A specially constructed mechanical watch that provides a minimum of 168 hours or one week of power reserve. The "Hebodmas" (the name means "seven days"), which debuted in 1913, had a large barrel that covered the entire surface of its movement. The long, shaped movements of the 1930s had normal-sized barrels, but their gear trains were augmented with two additional intermediate wheels. An eight-day movement is an unusual and special feature for domestic and other larger clocks. Interesting wristwatches with long-duration power reserves became available again around 1990. To help their owners remember to wind them, these mechanical marathons typically have power reserve displays.

Elegant watch
An elegant watch model typically has three hands to show hours, minutes, and seconds, as well as a particularly slim case and discreet design. Because of their puristic design, elegant watches can be combined particularly well with clothes and are appropriate for almost any style of dress.

Émail (enamel)
“Émail' is the French word for 'enamel', a vitrifiable substance that can be given various colours and fused onto the surface of metals, either to protect or to decorate the substrate. Enamel consists of silica sand and calcium fluoride to which lead oxide, borax and soda ash are added. The mixture is first melted at 1,200 degrees Celsius, then flash cooled. The resulting granules are ground into powder together with the colouring agents, which include: antimony, zirconium oxide or titanium dioxide for white enamel; cobalt oxide, chromium oxide or other colouring agents for coloured enamel. Layers of enamel are brushed or sprayed onto the clean metal substrate, or the entire metal piece is dipped into the enamel. Then the coated piece is fired in a special oven at a temperature of 800 to 900 degrees Celsius. The enamelling technique has been used on watch dials and cases for over 350 years. During the first decades of the 20th century, enamelled dials were practically standard equipment on fine wristwatches. Partly due to the expense involved in their manufacture, enamelled dials have become rather rare in recent decades.

Endstone (Jewel Cap)
An unpierced jewel, flat on one side and convex on the other. The flat side of the endstone is placed on the balance jewel to limit the vertical play of the balance staff. Balance rod bearings are generally fitted with end stones. In the highest quality gauges, end stones are also used for pallet rod and escape wheel bearings.

The potential to complete work. Potential energy is needed to power the gear train of a clock. In a mechanical watch, the source of this energy can be a mainspring (spring force) or a lifted weight (force of gravity). The electrical energy required by a quartz clock can be supplied by an accumulator, a battery or a capacitor.

Error of the centre of gravity
In theory, it should always be possible to create a perfectly balanced assembly consisting of the balance and its spring. Even in practice, near perfection is not unattainable. Perfection can be achieved by adjusting the weight screws on the edge of the balance, or by milling grooves or drilling holes in the rim. But the pleasure derived from this elaborate 'balancing act' is short-lived because sooner or later the centre of gravity almost always moves away from the centre of the balance. This results in errors in the centre of gravity affecting the speed of a mechanical clock held upright.

A mechanism that incrementally channels energy from the mainspring to the oscillating systems (balance and balance spring) of a watch and prevents the gear train from running forward uncontrolled. Among its other components, the escapement consists of the escape wheel with its pinion and pallets with its twin pallet jewels and fork. Most of today's high-quality wristwatches are based on a Swiss anchor escapement. This name comes from the specific shape of the pallets and the geometry of the escapement system, which was invented in Switzerland. The escapement of a mechanical wristwatch performs a very arduous job. If the frequency of the balance is 28,800 beats per hour, the escapement allows the gear train to advance 691,200 individual increments each day. After four years, this is equivalent to more than one billion pulses and exceeds the work of a human heart by six times.

The French term 'établisseur', for which there is no English equivalent, indicates a watchmaker who buys components (movements, dials, hands, cases, etc.) from specialist manufacturers, then further processes and assembles these components to produce complete watches.

The steel and brass components of very fine watches have faceted edges (chamfering). Chamfers on the edge of the part should ideally form an angle of 45 degrees.

Fine adjustment
A mechanism used to make slight alterations in the position of the 'index finger (or adjuster). A large number of different constructions can be used to make fine adjustments in mechanical watch movements. The swan-neck fine adjustment is among the most unique of such mechanisms. A system that relies on an eccentric screw is much more common. A widespread but mistaken belief insists that a fine adjustment mechanism necessarily goes hand in hand with greater precision. Watches can be adjusted with a high degree of precision simply by carefully positioning the ordinary tail of the index finger, although this operation requires extreme care and dexterity.

Fine-tuning mechanism
For example, the neck of a swan with a finely threaded screw. The entire montage is attached to the balance cock, where it allows a watchmaker to shift the index position in minute increments.

The ratio of the weight of the precious metal (e. g. platinum, gold or silver) in an alloy to the total weight of the alloy. Nowadays fineness is expressed in thousandths or carats. Pure gold is 1,000 or 24 carats. The value of a carat is 1/24 of the total weight: 1,000 divided by 24 is 41,666. Fourteen carats therefore correspond to 585 / 1,000. Eighteen carats correspond to 750 / 1,000.

The final work of assembling the parts of a watch and putting its case into feature.

Flyback chronograph
A special mechanism controls two chronograph seconds hands that are one above the other, thus enabling two or more events that start at the same time to be timed simultaneously (e.g. the individual finish times of sprinters who started a foot race at the same time). A complex additional switching mechanism couples the flyback hand with the chronograph seconds hand. A special pusher stops the flyback hand so that an intermediate time can be read while the chronograph seconds hand continues to move in the plane below the flyback hand. When this same pusher is pressed again, the flyback hand rejoins its companion. The original flyback chronographs debuted in 1883. Wristwatches with flyback chronographs were first sold in 1920. Due to the elaborate and thus very expensive technology inside them, such watches have always been very special objects.

Number of oscillations per unit of time, expressed in hertz ( Hz). Most stationary clocks rely primarily on a pendulum as the speed regulating organ. Portable clocks are generally equipped with a balance. Both organs oscillate at a particular frequency. The pendulum of a seconds pendulum clock takes exactly one second to complete the arc from one turning point to the next, so it has a frequency of 0.5 Hz or 1,800 beats per hour (A / h). Early balances increased the oscillation frequency to 7,200 or 9,000 beats per hour. The frequency of balances in pocket watches was first increased to 12,600 and later to the typical standard of 18,000 beats per hour (2.5 Hz). In wristwatches, too, the latter frequency balance has become the norm. To improve accuracy, some watch manufacturers have further increased the frequency of the balance to 21, 600 A/h (3 Hz), 28,800 A/h (4 Hz) or even 36,000 A/h (5 Hz). However, balances oscillating at higher frequencies also require more energy than balances at slower rates. In addition, as rotational speeds and centrifugal forces increase, considerable lubrication problems arise. Modern quartz watches oscillate at a frequency of 32,768 Hz.

Full calendar
A complete calendar with displays by day, date and month. Manual resetting of the date and month display is necessary at the end of months that have less than 31 days. Some wristwatches with complete calendars automatically advance the month display to midnight on the day when the date display has reached '31'.

Gear Train
In a normal hand-wound watch, the gear train consists of five pairs of wheels with their respective sprockets. The teeth along the periphery of the barrel mesh with the leaves of the sprocket of the middle wheel, which is attached to the same stick that carries the middle wheel. The teeth of the middle wheel mesh with the leaves of the sprocket of the third wheel. The third wheel meshes with the sprocket of the fourth wheel. The fourth wheel engages with the escapement wheel sprocket. The energy flows through the escapement wheel and other parts of the escapement system, eventually reaching the scale, which is thus kept in motion.

Geneva Seal of Quality
A law passed on December 6 on 1886 to regulate the voluntary monitoring of pocket watches formed the legal basis for the so-called "Geneva Seal of Quality" or "Poinçon de Genève." It established strict quality standards for watch production in Canton Geneva. This regulation was made considerably stricter in 1957. From that year on, watchmakers who wanted their watches to bear the coveted mark were required to meet 11 quality standards. The rate accuracy of a watch also occupied the focal point of interest. Wristwatches with movements 30 mm or less in diameter had to undergo an 18-day testing program. Only if the movement met all the criteria did it qualify to carry the "Poinçon de Genève." The most recent version of the regulation dates back to December 22, 1994. The prerequisites for receiving the Poinçon de Genève are the numbering and submission of all candidate movements to the "Geneva Office for Voluntary Monitoring of Watches." The main contents of the regulations concern the determination of twelve criteria regarding the quality level of all components and their workmanship. Among other details, steel parts must have polished edges and satin-finished front surfaces. Screw heads must be polished or circular-grained; slots in screw heads must be beveled. Other provisions specify the details on jewels, gears, and pivots, the affixing of the balance spring to the balance cock, the technical execution of the very important oscillating and escapement system, the care in the workmanship of winding and hand. adjustment of the organs, and the work that must be devoted to the construction of the other components of the movement. Unlike the text of the 1957 law, current regulations no longer set minimum standards for the accuracy of the frequency of the submitted movements. Then as now, however, candidates for the Geneva seal of approval must be assembled and adjusted within the territory of the canton of Geneva.

Geneva Waves (Code Genève)
A rib-shaped embellishment commonly seen given mainly to fine- calibre bridges and cocks. Geneva Waves are applied before the components are electroplated, but remain visible even after that treatment. Geneva waves are generally only found on high-quality movements.

Glucydur Balance
The Glucydur balance is a modern balance that replaced bimetallic balance scales in high-quality watches after the invention of the balance spring. Glucydur balances are made of a copper alloy containing a mixture of approximately 3% beryllium. Glucydur can be recognised by its golden colour. The simpler nickel balances, on the other hand, have a silvery hue. Glucydur balances have a hardness of 380 Vickers; nickel balances have a hardness of 220 Vickers; brass balances have a hardness of 180 Vickers. The higher hardness of glucydur balances makes them more suitable for riveting, balancing and fine tuning.

Greenwich Mean Time. Synonyms are World Time or Universal Time Coordinate (UTC). The prime meridian, i.e. zero degrees longitude, passes from north to south through the centre of the GMT time zone. Mean Time at the Greenwich Observatory in England is used as the standard for navigation and international radio communication purposes.

A precious metal with a specific gravity of 19.5. Gold with varying degrees of fineness is used for jewelry and watch cases. In very fine mechanical watches, gold can also be used as a material for the adjustment screws on the edge of the balance wheel, jewelry mounts, wheels, or even the entire movement.

Gold filled
A gold coating applied to a non-precious support material, e.g., Brass.

Grande Complication
Highly complex pocket watch or wristwatch equipped with one or more of the following features: chronograph, perpetual calendar, minute repeater, etc.

Grande Sonnerie
A large striking mechanism that, depending on the specific version, automatically emits an acoustic signal to announce the arrival of full, half and quarter hours. A second barrel is integrated into the movement to power this mechanism. As a rule, grand strike timepieces also have a sliding piece that can be moved to deactivate the audible mechanism. The grand strike is often combined with a repetitive movement.

The gravitational attraction of the Earth pulls all bodies towards the centre of the planet. The acceleration experienced by bodies in free fall is measured in 'g'. The influence of gravity on the speed of a mechanical watch should not be underestimated. Especially in pocket watches, which are typically worn in an upright position, gravity can cause significant disturbances in the speed behaviour if the centre of gravity of the balance is not exactly centred on the balance staff. Only if it is absolutely centred is there no point along the edge of the balance that is continuously attracted towards the centre of the Earth with a force greater than all other points along the edge, thus causing both acceleration and deceleration.

Gregorian Calendar
After many years of preparation, and soon after the total abolition of ten whole days, a calendar reform ordered by Pope Gregory XIII came into force in Rome on 15 October 1582. This reform eliminated the tiny residual error contained in the Julian calendar, which had been in force since 45 BC and according to which the year was too long for a fraction of a day: 0.0078 x 24 hours = 673.92 seconds too long, to be exact. The Gregorian calendar compensates for this small error by decreasing the leap year by three leap years every 400 years. Whenever a secular year arrives (i.e. a year whose last two digits are 'zero') that is not divisible by 400, that year is not a leap year. Thus, there will be no 29th February in the years 2100, 2200 and 2300 AD.

Guilloché (Engine Turn)
To engrave, with the aid of a rose engine, the case or dial of a watch with a decorative pattern of thin, sometimes criss-crossed or artfully interwoven lines.

Gyromax Balance
In the early 1950s, the watchmakers at the house of Patek Philippe discovered that the new gyromax balances, which no longer required screws for inertial weights on their rims, could be built with larger diameters without significantly increasing their weight. The larger diameter went hand in hand with an increase in the balance's moment of inertia, which led to improvements in the frequency performance of a watch. Patent protection was granted to the 'Gyromax' balance on 31 December 1951. On this type of balance, eight disc-shaped regulating elements are carried on axially arranged pivots. The elements can be rotated. This exceptional development can be seen as the forerunner of the modern ring scale, which has no screws.

A clock with a sprung lid with a circular opening in the centre through which the time can be read when the lid is in the closed position. This type of case was most common on pocket watches. Before the introduction of the first shatterproof watch crystals in the 1920s, hunter cases were also sometimes used on wristwatches. Half-hunter pocket watches usually had a glass pane in the circular opening; half-hunter wristwatches usually did not have this pane.

A mark stamped on the case of a watch in order to provide information, for example, on the type and fineness of the precious metal, the country (and sometimes the city or canton) of origin, the year of manufacture, and the identity of the case manufacturer. The trademark or logo of the company that manufactured or delivered the watch, a reference number, and a serial number are also often stamped on the case.

Hand-wound clock
Watch whose mainspring requires manual winding.

Heures Sautantes (Jumping Hours)
A mechanism in which a disc, printed with a series of digits from 1 to 12, replaces the hour hand. The current time is visible in digital format, i.e. it is displayed as one or more digits. One and the same number is visible for 60 minutes through a cut-out in the dial. After the minute hand reaches '12', this numbered disc suddenly jumps forward to display the next number, thus indicating that the next hour has begun.

Hook-tooth lever escapement
Another name for the Swiss anchor escapement. The name comes from the hook-like shape of the teeth on the escape wheel.

Hour counter
A detail in the construction of some chronographs, an hour counter counts the number of hours that have elapsed since the start of a stop time sequence. Most hour counters can count a maximum of twelve hours. When the return-to-zero button is pressed, the hour counter hand also returns to its initial position.

Watch whose case has both a back cover and a spring-hinged front cover to protect its crystal.

Hunter Calibre
A movement in which the fourth wheel and crown form a 90° angle with the centre of the watch. A small seconds dial is located at the '6'.

Illuminated dial
Dial from which the time can be read at night and without additional illumination. To do this, the numerals or hour markers and hands are filled with a luminous material. Only seven years after, when radium was discovered by Marie and Pierre Curie in 1898, the quinine factory Büchler & Co. in Braunschweig, Germany, began marketing luminous dials and watch hands. Pure radium is highly radioactive, so this element is no longer used on luminous dials. Tritium, a radioactive isotope of hydrogen with an atomic weight of 3, also became obsolete. Watches with tritium as the luminous material can be recognized by the words "Swiss Made - T" on the dial. Instead of these radioactive substances, modern luminous dials are based on alternative substances that are not radioactive but still luminous, for example Super-LumiNova.

Impact absorption
A system to protect the fine and therefore very delicate pins of the balance staff from breaking. To do this, the jewellery and terminal stones in the balance staff's bearing are resiliently secured to the scale plate and spigot. When the watch is hit by a strong blow, these jewels collapse laterally and/or axially. A shock-absorbing watch should be able to survive a fall from a height of one metre onto a wooden floor undamaged. After the drop, the speed of the watch should not show any major deviations. Watches with shock-absorption systems were first marketed in the 1930s. Shock absorption had become standard equipment by the 1950s. Originally, many watch brands used their own shock-absorption systems (partly to reduce costs), but these systems did not survive in the long term. The best known and most widespread shock-absorption systems are the so-called 'Kif and Incabloc' systems. The latter can be recognised by its stabilising spring, which is shaped like a lyre.

Incabloc, one of the most common and widely used shock- absorption systems for mechanical watches, was first mass-produced in 1933. It is generally recognised as the most successful shock-absorption system in the history of portable watches. Its success is partly due to the fact that this shock-absorption system can be easily integrated into all calibres. The Incabloc shock-absorption system is usually shaped like a lyre.

Developed by Portescap, this adjustment system for mechanical watches does not require the typical index. The outer end of the balance spring is squeezed between two elastic rollers. The position of one of these rollers can be shifted with the help of a star-shaped component, thus lengthening or shortening the balance spring and altering the speed of the watch. This operation would otherwise be performed by the indexing system, which is rendered unnecessary by the Incastar solution.

Independent Seconds (Dead Seconds)
The text of a patent granted to a movement with a jump-type seconds hand describes the independent seconds mechanism as "a mechanism for the gradual forward movement of the seconds hand on a gear-driven watch movement." In essence, this is nothing more than an ordinary mechanical caliber. On a watch whose balance wheel has a frequency of 18,000 beats per hour, the independent seconds mechanism counts five vibrations, then releases the seconds hand, which (as on a quartz watch) jumps forward in a full-second increment.

Indirect central seconds
In clock movements with indirect central seconds, the pulse of the second hand comes from outside the flow of energy passing through the gear train. For this reason, this type of seconds mechanism is frequently found on gauges that were originally built to support small seconds counters and later rebuilt to support an "sweep". Modern gauges are generally built to support a centrally axial " sweep". For this reason, they usually have direct central seconds, that is to say, the pulse for the second hand is within the flow of energy passing through the gear train.

Inner Cover
An additional protective cover (dome or cuvette) under the outer back cover of a watch. This type of additional cover is most commonly found on pocket watches. Early wristwatches with hinged cases sometimes also had inner covers.

Jewel Hole
A cylindrical-shaped synthetic gemstone (usually a ruby) with a hole in the centre. Jewels are pressed into plates, bridges and taps to reduce friction and minimise wear in pivot holes drilled into planar components. The rapidly rotating pivots of a gear train rotate inside the jewellery. In very fine watches, the walls of the holes in the jewellery are not cylindrical, but are rounded into an olive-like shape, hence the technical term 'olive' or 'olive-cut jewellery hole'. The rounding on the walls of the hole further reduces friction in the bearing because it minimises the contact area between the jewel and the pin. In addition, an olive-cut jewel hole gives the pin greater freedom of movement.

Jeweled pallets
Pallets fitted with ruby jewels.

To reduce friction in precise watches, precious stones are inserted at critical points, e.g. on the impulse faces of pallets and the impulse pin (roller pin). In the past, natural precious stones (e.g. rubies or sapphires) were used. Nowadays, most modern watches are based exclusively on synthetically manufactured jewellery. One can distinguish between bearing jewellery with holes, end stones (cap jewellery), pallet jewellery and roller pins (impulse pins). Just because a movement has a large number of jewels does not necessarily mean that it is a particularly high-quality movement. On the contrary: the dial of a cheap wristwatch may boast that the movement contains a large number of 'jewels', which could lead an uninformed person to assume that it is a high-quality watch.

Julian calendar
The familiar cycle of three ordinary years of 365 days followed by a leap year of 366 days was initiated by the Roman emperor Gaius Julius Caesar. The year was defined by the Julian calendar, however, is 0.0078 days longer than the actual astronomical year. Pope Gregory XIII corrected the error, which had accumulated to ten full days over many centuries, by instituting the Gregorian calendar in the year 1582.

A device similar to a tourbillon. The karussel was invented in 1892 by a Danish watchmaker named Bonniksen as an alternative to the tourbillon, which is more difficult to make and considerably more expensive. A tourbillon generally rotates around its own axis once a minute. The oscillation and escapement system inside the karussel describes a 360° circular arc once every hour. Some karussels have a shorter orbital cycle. Besides its slower rotation speed, another essential difference between a karussel and a tourbillon lies in the propulsion of the rotating organ. A tourbillon is rotated by the fourth wheel, which means that the rotations of the tourbillon cage are indispensable for the forward and backward oscillation of the balance and thus for the functioning of the entire movement. If the tourbillon stops, so does the entire watch movement. A karussel is usually driven by the third wheel. The watch therefore continues to run even if the karussel, which is usually made as a plate, should stop. Karussels were first incorporated into wristwatches in 2001.

Keyless watch
A clock whose mainspring is wound through the crown.

The surfaces or edges of watch components can be honed and polished with the help of a lapping machine (or polishing machine). This polishing enhances the visual appearance and value of a movement.

Abbreviation for "liquid crystal display." When pressured by an electric field, a liquid crystal film refracts incident light. This feature makes these crystals very useful for digital quartz watches. LCDs replaced LEDs in the mid-1970s. Rather than generating its own light, an LCD refracts light falling on it. The advantages of this are: - less electric current is used - the display is continuously visible and does not need to be specially activated first - good visibility is provided in different lighting conditions - the assembly requires no moving parts. In its simplest version, an LCD consists of two glass plates, each of which is coated on its inner surface with a layer of electrodes. Between the two plates are nematic (filiform) liquid crystals that have elongated molecules and a nearly parallel sorting structure. The liquid crystals undergo excitation when the electrodes are exposed to an electric field. If no field is present, the coating is clear and transparent. When current flows through it, the coating becomes turbulent, refracts light and appears cloudy.

Leap Year
According to the Julian calendar, every four years has an extra day added at midnight on 28 February. Because of this additional day (29 February), a leap year has 366 days, instead of the 365 days that make up a normal year.

Abbreviation for "light-emitting diode." These optoelectric elements were used in the 1970s to tell the time on quartz watches. Because the display absorbs so much energy when it is on, it was kept dark unless it was specially activated by pressing a button. This defect soon led to its obsolescence, and the LED was replaced by the LCD display.

Lépine calibre
In this form of construction for watch movements, named after the French watchmaker Jean-Antoine Lépine, the wheels and balance wheel share a common plane and slide on one side of the plate under the bridges and cocks. Moreover, in a Lépine calibre, the winding crown with adjustment, the centre of the dial and the axis of the seconds hand are all aligned along the same line.

Lever escapement
This is currently the most commonand used type of escapement in mechanical watches. It was invented around 1710 by English watchmaker George Graham (the so-called "Graham deadbeat escapement") for use in large clocks. Beginning in 1757, Graham's student Thomas Mudge gradually developed the anchor escapement so that it could also be used in pocket watches. Portable watches are based on various types of anchor escapements. Their names vary according to the shape of the pallets and include: the English lever escapement (which has pointed teeth on the escape wheel), the Glashütte lever escapement, the Swiss lever escapement, and the pallet escapement. The Swiss anchor escapement unquestionably dominates the field nowadays. The pin-pallet escapement is quite rare and is typically found only in very simple cases.

Traditional unit used to measure the size of clock movements. Ligne is derived from the ancient French foot or "pied due roi." A common diameter for circular movements is 11 lignes. Rectangular movements sometimes measure 8¾ x 12 lines. One line is equivalent to 2.2558 millimeters. One French foot is equivalent to 12 inches or 144 lines. A foot is abbreviated with a single apostrophe ('); an inch is abbreviated with twin apostrophes (''); a line is abbreviated with three apostrophes (''').

Lunation (lunar month)
During a lunation, which is equivalent to about 29.5 days, the moon progresses through a complete cycle of its phases: that is, from the new moon, first quarter, to the full moon and last quarter, to the next new moon.

Main spring
A mainspring is a long, elastic, coiled strip of steel. Main springs were first used to store energy for mechanical clocks during the 15th century. A mainspring is wound inside a barrel. The torque provided by a mainspring is greatest when it is fully wound. As the spring gradually loosens, its torque continuously decreases, which has a negative effect on the speed of the watch. A self-winding watch regularly tightens its mainspring. This leads to a relatively constant torque level and thus a regular speed. Modern wristwatches generally use mainsprings made of "nivaflex," a special alloy that can be used to make a durable elastic spring that is highly resistant to breakage. The S-shaped "nivaflex" spring releases its energy reserve on a regular basis.

Maltese Cross
Vacheron Constantin's trademark is in the shape of a Maltese cross. A similarly shaped component is used to limit the extent to which the barrel can be wound. Together with a finger mounted on the barrel shaft, the Maltese cross compensates for major torque differences in the ignition of mechanical and gear-driven watches. This elaborate technique is only rarely used nowadays and is only found in particularly fine watches.

According to the unwritten laws of watchmaking, a company that makes watches can only call itself a "manufacture" if it makes at least one ebauche (vacuum movement). Companies whose craftsmen assemble ready-made ébauches to produce finished watches are known in the industry as "établisseures." The small, elite circle of mechanical watch manufactures currently includes Audemars Piguet, Chopard, Roger Dubuis, Girard-Perregaux, Glashütte Original, IWC, Jaeger-LeCoultre, A. Lange & Söhne, Patek Philippe, Piaget, Rolex, and Zenith, among other names.

As a watchmaker jargon, the French word for "marriage" describes the compilation of many authentic components taken from several different watches that are assembled in order to create a entirely new watch. Well-made mariages are difficult to identify, but even successful ones significantly reduce the value of a watch.

Mechanical gear train clock
A clock or watch powered by a spring or descending weight. Speed regulation of these timepieces is reached with the balance of wheel and a spiral or an oscillating pendulum. The development of the mechanical gear train clock probably resulted from the mechanism used to drive planetaria, i.e., devices representing the motion of the planets. The earliest artifacts date back to the late 13th century. The oldest mechanical gear train clock in German-speaking Europe is probably the Strasbourg cathedral clock; this clock was completed in 1352. Functional gear train clocks first appeared in England in the late 13th century.

Megahertz (MHz)
A unit of frequency indicating one million cycles per second.

Micro rotor
A rotor, integrated into the movement plane, that automatically winds the mainspring of a self-winding watch. The motivation behind the invention of micro-rotor gauges was the desire to build very thin and therefore very elegant self-winding wristwatches. Building on old-fashioned hammer-style oscillating weights (moving only through an arc rather than completing a complete circle) or relying on central rotors, Universal Genève followed suit in 1958 with the slim "Polerouter." Piaget introduced the Caliber 12 Pl in 1959: just 2.3 mm thick, it was the thinnest automatic watch in the world. Patek Philippe's classic Caliber 240, 2.4 mm thin, has a micro-rotor made of 22-carat gold. Chopard's LUC 1.96 debuted in 1996: this in-house caliber has double barrels, is 3. 3 mm thick (including the jump date display) and has a power reserve of about 70 hours. are both located in a plane above the movement plane and are consequently thicker than micro-rotor calibres. Micro-rotor calibres have not captured a very large share of the market, but they have nevertheless become a fixed feature in watch technology. The pioneer of the micro-rotor was Büren Watch Co. which received a corresponding patent in 1954. Three years later, this company debuted its "Super Slender," which was only 4.2 mm thick, but they still became a fixed feature in watch technology. The pioneer of the micro-rotor was Büren Watch Co. which received a corresponding patent in 1954. Three years later, this company debuted its "Super Slender," which had a thickness of only 4.2 mm. but still became a fixed feature in watch technology. The pioneer of the micro-rotor was Büren Watch Co. which received a corresponding patent in 1954. Three years later, this company debuted its "Super Slender," which was only 4.2 mm thick.

One millionth of a meter or one thousandth of a millimeter. The thickness of gold plating on double watch cases is measured in microns, abbreviated by the Greek letter mu (µ). The double had a thickness of at least twenty microns. Nowadays five microns is a more common thickness.

With the introduction of mechanical geared clocks, the " civil" day was divided into 24 hours of equal length. The word "minute" comes from the Latin phrase "diminutiva pars," meaning "a diminished part of a whole." The Babylonians pioneered the sexagesimal system, which is based on the number "60."

Minute counter
Chronometers and chronographs often have a counter to calculate the number of minutes that have elapsed since the start of a stop time sequence. Counters that total up to a maximum of 30 or 45 minutes are the most common. These can be found, for example, on chronographs used by referees officiating at football matches. Other counters may count a maximum of only 15 or a maximum of 60 minutes. When the seconds hand of the chronograph or chronometer is returned to its zero position, the hand of the minute counter also returns to its original position.

Minute repeater
Minute repeater watches strike one or more chimes to audibly announce the hours, quarter hours, and number of minutes elapsed since the last quarter hour. Their very complicated movements usually have two hammers striking two gongs. Each full hour is announced by the sound of the hammer with a corresponding number of strikes against a low gong. Minutes resound from a higher gong. Quarter hours are announced by double strikes (high low). The first minute repeater timepieces were made around 1750. They were and still are the glory in the art of creating repeater trains.

A group of constructions. Among other applications, modules are used in many self-winding chronographs. They are typically mounted on the front (dial side) of the movement. A friction joint is usually used to connect the module with the energy flow moving through the gear train. Modular constructions can usually be recognized without opening the case by the date window, which tends to be deeper below the dial and usually has a magnifying glass integrated into the glass above it, and by the V-shaped arrangement of the pushers and crown . Modules are also found in calendar watches, mainly on models that have so-called "perpetual calendars." In such watches, the entire calendar mechanism is mounted on its own plate, which is attached to the side of the movement dial. There are also strike train modules.

Moon Age display
An indicator showing the number of days since the last full moon. In a synodic month, the interval from one new moon to another is exactly 29 days, 12 hours, 44 minutes and 3 seconds. The typical lunar phase displays are made up of a disk, cut around its periphery with 59 teeth and with two full moons printed or painted diametrically opposite each other on its surface. Powered by motion, this display requires two lunations to complete a full rotation around its axis. The current moon phase can be determined by looking through a specially cut shaped opening in the dial. A correspondingly divided scale surrounds the periphery of the moon phase indication. Views of the age of the moon deviate from astronomical reality by about eight hours per year.

Moon phases
As a result of cyclical changes in the positions of the sun, moon and Earth, the moon appears to pass through four phases (new moon, first quarter, full moon and last quarter) before returning to the new moon. The time elapsing from one new moon to the next is approximately 29.5 days.

Motion Work
A gear train located between the plate and the dial. It transmits and translates the rotation of the minute pinion into the hour hand. In addition, in combination with the hand adjustment system, the dial train allows the positions of the hour hand and minute hand to be exactly reset after the crown has been partially pulled out.

French watchmakers use this term to refer to the movement of a watch.

French term for a watch that is as transparent as possible and in which neither the movement nor the means of propulsion are visible.

A watch is nonmagnetic when it is protected from the deleterious effects of magnetic fields. To achieve this, components most susceptible to the disturbances of magnetism are made of materials that cannot be easily magnetized (for example, balance springs made of elinvar or nivarox are used in conjunction with balances made of brass, nickel, or beryllium bronze). In addition, various nonmagnetic metals are also used for components such as pallets, escape wheel, and roller (or roller table). Another option is to enclose the entire movement within an additional inner case made of a highly conductive alloy. This inner case prevents the formation of magnetic fields inside it.

The unit of measurement used for all civilian timekeeping is the progress of the sun in the sky. True noon is defined as the time when the shadow cast on the ground by a vertical pole is shortest.

Number of vibrations
The sum of the beats of the speed regulating organ ( e.g., Pendulum or balance wheel) of a clock is described as its "number of vibrations." A complete oscillation consists of two sequential vibrations. For example, classical wristwatches generally have an oscillation frequency of 18,000 vibrations (or "beats") per hour. In other words, the balance completes 9,000 oscillations (beats) or 18,000 half-oscillations (vibrations) per hour. The frequency of the balance of such a clock is 2.5 hertz (Hz).

One-handed watch
Early gear-driven watches were equipped with a single hand, ie. an hour hand. Abraham-Louis Breguet's famous "Souscription" pocket watch was a one-hand watch. The time can only be approximated by consulting the dial of a one-handed watch. Wristwatches of this type are rare, but not entirely nonexistent.

Oscillating mass
In a self-winding movement, the oscillating mass is a body free to rotate and connected to the barrel by a gear train. When the movement is in a non-horizontal position, gravity causes this heavy mass to fall toward the center of the Earth. The kinetic energy generated during this fall is transferred by a gear train to the barrel, where the main spring stores it as potential energy.

One of the most complex components in mechanical clocks, pallets are shaped like a ship's anchor, hence the French name "ancre." Usually made of brass or steel, pallets consist of several components, including the lever, the pallet staff, the pallet stones, and the arrow or protective pin. The purpose of the pallets is twofold: it conveys energy from the gear train to the scale, keeping the latter in oscillation and prevents the gear train from running ahead and quickly exhausting the energy available to it from the barrel.

Pallet escapement
In a pallet escapement, the role that would otherwise be played by the pallet stones is played by steel pivots that rise vertically from the pallet plane. These pins engage with the teeth of the escape wheel.

Pedometer winding
An automatic winding system using an oscillating mass which, like the oscillating mass in a pedometer, oscillates back and forth when the person wearing the watch walks. A gear train transmits the kinetic energy to the mainspring. The winding of the pedometer is considered to have been invented by Abraham-Louis Perrelet of Le Locle, Switzerland, in 1770. The first wristwatches with this type of winding system were marketed in the 1920s, for example by Léon Leroy (1922) and John Harwood (1924) . The winding of the pedometer was still used in some wristwatches until the 1950s.

A synonym for automatic winding or self-winding. The word is used, for example, in the name of the "Rolex Perpetual."

Perpetual calendar
A calendar mechanism that automatically takes into account the varying lengths of the months and will not require manual adjustment until midnight on 28 February 2100.

Plaqué d'Or
Thin layer of gold galvanically applied to the surfaces of watch cases that are made of non-precious metals. See also doublé.

Sometimes called a "movement plate," this term designates a metal plate that carries the bridges (bars), cocks and other components of a watch movement. The dial (movement) train is located on the dial side of the plate. The entire gear train and barrel, as well as the oscillating and escapement system, are attached to the back of the plate under the bridges (bars) and cocks. In addition to threaded holes that accept screws, the plate is also drilled with holes for the feet and bearings of the gear train.

A very discrete and extraordinarily valuable metal used in the manufacture of watch cases. The high price of platinum stems from its extreme rarity, as well as the difficulties involved in mining, refining and processing. To recover one gram of platinum, more than 300 kilograms of ore must be extracted. Only 100 kilograms of ore must be mined to recover one gram of gold. In addition, the successful processing of platinum places stringent requirements on a metallurgist. Platinum has the highest melting point of all precious metals: it melts at 1,773 degrees Celsius, compared to 1,063 degrees for gold and 960 degrees for silver. Platinum is also harder, stronger and heavier than other metals used in jewelry, which means that special tools and production techniques must be used to work platinum. Finally, platinum watch cases usually have a fineness of 950, meaning the alloy is 95 percent pure platinum. A platinum watch case weighs about 35 percent more than an identical 18-karat gold case.

Unlike pocket watches, which usually remain in an upright position inside the waistcoat or trouser pocket, wristwatches are worn in many different positions, e.g. 'crown up', 'crown down', 'crown right', 'dial up' and 'dial down'. Precise watches are then adjusted to each of these five positions.

Power reserve
Additional running time provided by stored energy in excess of a watch's normal winding interval (24 hours). The power reserve generally varies between 10 and 16 hours. The driving force provided by the mainspring decreases during this interval, which leads to a reduction in speed performance.

Power reserve display (Marche)
An indication of the remaining power reserve available for a mechanical movement. Power reserve displacements were first used on marine chronometers because the degradation of such a clock and the consequent loss of the exact time on the high seas could be a disaster for navigation and sailors who depended on accurate navigation. For this reason, each glance at the dial also kept a sailor informed about the momentary state of the spring. When self-winding mechanisms began to make their way into wristwatches, the display proved that the self-winding mechanism worked properly.

Precious metal
Wristwatch cases are usually made of precious metals such as gold, platinum or silver. Gold is available in alloys having a fineness of 333 / 1,000 (8 carats), 375 / 1,000 (9 carats), 585 / 1,000 (14 carats) or 750 / 1,000 (18 carats). Mixing other metals (e.g., Copper) to the alloy alters the hue of the gold alloy. If gold is used as the rotor material for a self-winding wristwatch, the most commonly used alloys are 21 karat, 23 karat or 24 karat gold. The fineness of platinum is 950 / 1,000. The disadvantages of silver watch cases are that they are very soft and tarnish easily. Covering them with a layer of gilding (vermeil) effectively prevents tarnishing, but it suffers from the same problem that plagues double cases: sooner or later.

Precious Metal Control (Swiss)
A partial revision of Swiss laws regulating precious metals came into effect on August 1st, 1995. The following fineness designations have been valid in Switzerland since then for gold, silver and platinum: gold 333 585 750 916 999, silver 800 925 999, platinum 850 900 950 999. Palladium is recognized as a precious metal with the following fineness designations: 500 950 999. The minimum thickness for gold, platinum and palladium plating has been reduced from 8 to 5 microns. Ten microns is the minimum for silver plating. The quality designation "coiffe o" is allowed only for watch cases or bracelets with gold plating at least 200 microns thick. The passage of this law also drastically reduced the number of official hallmarks that can be stamped on the surface of jewelry or watches after passing a mandatory inspection by the Swiss Precious Metals Control Authority. Before July 31, 1995, there were individual hallmarks for each precious metal and fineness. After that date, there was only one hallmark (the head of a St. Bernard dog) combined with numbers designating the fineness grade.

Ticking counts among the oldest and most accurate mechanical machines in the world. If the movement of a watch deviates for one day (86,400 seconds) from the official norm of 30 seconds (a rather large error by contemporary standards), the arithmetic error of that movement would be 0.035%. In other words, its degree of accuracy would be an incredible 99.965%. Modern mechanical wristwatches are considerably more accurate, especially if they have obtained an official chronometer certificate. The rate deviation here is less than 0.005%.

Precision watch
A watch with a lever escapement or chronometer and assembled from high-quality components, including an oscillating system that can compensate for temperature variations. Precision pocket watches and wristwatches require at least fifteen functional jewels.

Derived from the Greek language, this term describes an original model or one that serves as an archetype upon which later versions are modeled. A prototype is the first example of a watch and is typically made by hand before mass production.

A labor-saving scale specially calibrated along the periphery of a watch (usually a chronograph) for medical purposes. As the name states, a pulsometer is used to measure a patient's pulse. Depending on the calibration of the scale, the user counts 20 or 30 heartbeats after starting the chronograph. The chronograph is then stopped, and the tip of the chronograph second hand indicates the number on the pulsometer scale that corresponds to the patient's pulse rate in beats per minute.

An organ by which a function can be controlled. For example, a push-piece can be used to unlock the hinged cover of a hunting watch, to start, stop, and reset the second hand of a chronograph to zero,to activate the striking work on some repeater watches or to reset the time zone on a world time watch.

Radio clock
In 1978, a law on the determination of time "Time Law" was passed in Bonn that instructed the Physikalisch-Technische Bundesanstalt (PTB) [Federal Center for Physics and Technology] in Braunschweig to "represent and disseminate legal time." Four highly accurate cesium clocks in the Braunschweig facility detect time 100,000 times more accurately than the Earth. According to the law, the time detected by these clocks is transmitted by a DCF 77 longwave transmitter in Mainflingen, near Frankfurt am Main. Anyone within a radius of 1,500 kilometers who has an appropriate receiver - a so-called "radio clock"- can use this time signal for free. The exact time, including the correct date, day of the week and month, is transmitted directly to the wrists of people wearing radio wristwatches. In case of a temporary loss of transmission capability, or if the recipient is outside the range of the signal, a normal quartz movement in the watch or radio watch can continue to keep accurate time. As soon as the next radio signal is received, the radio clock displays are automatically synchronized with the normal time transmitted by the Braunschweig cesium clocks.

Rapid oscillator
Watch movements whose balances oscillate with a vibration number or frequency accelerated to 28,000 or even 36,000 beats per hour to minimize their susceptibility to disturbances.

Specific to each manufacturer, the reference is an alphanumeric sequence used to classify the specific manufacturer's clock models. The reference number often contains information about the type of watch, case material, movement, dial, hands, strap, and presence or absence of gemstones.

Regulator dial
Off-center display of hours and seconds. A seconds hand whose axis is not in the center of the dial allows the seconds to be read almost entirely without interference from other hands that rarely eclipse it. Dials of this type were developed for the so-called "regulators" (precision watches) that were used to keep time in observatories and watch factories, where timekeeping to the nearest second was often essential. The Swiss watch industry debuted the first wristwatches with regulator dials in the 1930s. Only a few models were launched, none of which achieved widespread popularity.

Repair mark
After a watch has been repaired or refurbished, and sometimes even before a watch is sold, some watchmakers stamp a repair mark (usually on the back of the watch case). This mark indicates when maintenance was carried out and protects a watchmaker from unwarranted claims. Connoisseurs can determine the age and some other facts about the watch's 'career' by reading the number, type and (if present) date on the repair mark.

Repassing (finishing)
Complete (final) inspection of a completed clock before it leaves the production site. Finishing also includes checking the rate of the watch. In the past, repasseurs (finishers) were the aristocrats among watchmakers.

Repeater Strike Train
An elaborate additional function that allows the movement of a clock to audibly announce the current time with greater or less accuracy. Depending on the details of the strike, quarter-hour, eighth-hour (7 1/2 minutes), five-minute, or one-minute repeater clocks can be distinguished. The strike train needs energy to announce the time audibly. It receives this energy when the strike train mechanism is activated. This mechanism is activated by moving the position of a slide or pressing a button in the edge of the case. If the slide or button is not fully moved to its limit position, simple repeater clocks do not fully chime the time. In finer constructions, an "all or nothing" safety device prevents this problem.

Retrograde display
A hand that indicates the time, date or day of the week by advancing incrementally along a calibrated arc and then, when it reaches the end of its arc, rapidly returning to its original position.

Rhodium plating
Galvanic ennobling applied, for example, to movement surfaces. Rhodium plating can protect from oxidation and impart a brilliant glow to surfaces. In addition, rhodium creates a harder surface;rhodium can be refined from platinum ore, so it is counted among the metals in the platinum group.

Rotating cage
A delicate cage, often made of steel. Titanium or aluminium are often used as the material for this assembly on modern wristwatches. On watches equipped with a tourbillon, this cage contains the oscillating and escapement system (consisting of the balance, balance spring, pallets and escape wheel). The cage rotates around its own axis, usually at the rate of one rotation per minute. A rotating cage should be robust, filigree and as light as possible. Making this assembly is among the most demanding and laborious tasks of a watchmaker.

An oscillating mass that is free to rotate for 360° turn and used on self-winding watches. Depending on its design, a rotor mechanism may wind the mainspring in one or both directions of rotor rotation. A distinction can be made between central rotors and micro-rotors. The former rotate throughout the entire movement; the latter are integrated into the movement plane.

The gear train of a watch was first equipped with pierced rubies to minimize friction and wear by Fatio de Duillier and French watchmakers Pierre and Thomas Debaufre around 1700. The latter two watchmakers began producing pierced and unpierced jewels for watch movements in 1704. The first synthetic rubies were used in movements in 1902:the so-called "rubis scientifique" is hard and homogeneous, can be synthesized into any color and is relatively easy to work with. It replaced the so-called "reconstituted ruby," which is made by melting and pressing together fragments of scrap ruby. Synthetic rubies differ from natural rubies only in their genesis. The chemical composition of each is identical to that of the other.

Running time
The entire time of a mechanical movement, that is, the interval between the full winding of the spring and the stop of the hands due to insufficient energy in the loose spring.

Sapphire crystal
Scratch-resistant material, having a hardness of 9 on the Mohs scale, used for watch glass. Only diamond is harder than sapphire.

Satin finish
A matt, silky, fine polish given to metal surfaces.

Scale Hectometer (production counter)
Calibrations of a production counter help determine the production capacity of identical parts in a mass-produced item. The chronograph is started at the beginning of the process leading to the production of a mass-produced part in a series, then stopped again at the end of the process. The hand on the dial shows how many pieces were produced per hour. This assumes, however, that no more than 60 seconds are required to produce each part.

The duration of a” diminutive secunda pars“, that is, a” diminished second part " of an hour, has been redefined several times throughout history. These redefinitions were due in part to the enormous advances made in the science of time measurement. A committee composed of French scientists suggested in 1820 that a second should be defined as an 86,400 th of an average solar day. The irregularity of the Earth rotation determined empirically, together with advances in modern quartz timekeeping technology, has made this definition obsolete. A new definition was proposed in 1956, when the unit of time known as the "second" was redefined as 31,556,925.9747 th of the time it took the Earth to complete an annual orbit of the sun. Noon on January 1st of 900, was chosen as the time to begin counting these annual orbits. This minutely defined unit, however, did not survive very long because it was too inaccurate. A five-second detour would accumulate over a single millennium. Quartz timekeepers ceased to play a role in the shattering world of highly precise time measurement because they were replaced by atomic clocks in the late 50s, so scientists set themselves the task of finding a new definition. Since 1957, the second has been defined as the time it takes for the electronic hull of a cesium atom to complete 9,192,631,770 vibrations.

Seconds display
First introduced by Jost Bürgi in 1579, seconds were originally only displayed on very accurate watches. Today, a seconds hand is practically useless on watches and alarm clocks of all kinds.

Semi-perpetual calendar
A clock that correctly indicates the varying lengths of the months during a leap year cycle. The 29 February is unknown to it because it is missing a wheel that turns around its axis once every four years.

Circular piece of moulded metal with a slot to hold a jewel. To secure the setting to its bar (bridge), it is pressed or screwed into the bar. The original purpose of the setting was mainly aesthetic. Made of gold or a gold-like metal, settings were used to enhance the lustre and effect of beautiful jewellery. It was only later that watchmakers discovered the pragmatic purpose of settings. The jewel within a factory setting can easily be replaced if the stone breaks. In the wake of the automated production of watch movements, settings became increasingly common. Stamps could precisely drill holes in the bridge to accept settings. Settings became pointless after jewellery manufacturers became able to supply their products with absolutely impeccable quality and exactly identical dimensions. This jewellery could be pressed directly into holes drilled in bridges, rods and plates. Today, screwed settings are used because of their attractive appearance. They are most often found in movements made by watch manufacturers in Glashütte.

Shaped movement
A watch movement that is not circular. A wide range of movements of various shapes (e.g., tonneau-shaped, baguette-shaped, rectangular) have been developed, especially for use in wristwatches. Shaped movements have become quite rare nowadays.

Short-term measuring device
A watch that measures and supports the immediate reading of the duration of short intervals. By definition, such devices include chronometers and chronographs.

Skeleton movement
A watch movement whose plate, bridges, taps, barrel, and sometimes even rotor are pierced so that the only material remaining is that which is absolutely essential to the function of the skeletonized component. The elaborate piercing allows one's gaze to penetrate deep into (and sometimes through) the movement. Skeleton work is done manually and requires a highly skilled watchmaker. The quality of craftsmanship is most easily recognized in skeleton work at the points where the faceted edges meet. Three different types of angles can be differentiated: 1. The inserted corner. Two facets meet to form a recessed corner. The joint should be a perfectly straight line connecting the intersection points of the two edge lines. This type of corner, which can only be created by hand, shows that the skeleton work is of the highest quality. 2. The protruding corner. The joining of two facets forms a protruding corner. This corner should have a sharp edge and should be neither beveled nor rounded. 3. The rounded corner. Unlike the previous two shapes, the facet here does not have a sharp edge. Rounded corners are less artistic and less valuable than the other two types of corners because machines can also be used to create them. Wristwatches with skeletonized movements debuted in the mid-1930s. Rounded corners are less artistic and less valuable than the other two types of corners because machines can also be used to create them. Wristwatches with skeletonized movements debuted in the mid-1930s. Rounded corners are less artistic and less valuable than the other two types of corners because machines can also be used to create them. Wristwatches with skeletonized movements debuted in the mid-1930s.

Steering device for a chronograph. A mobile cam, the shape of which varies depending on the particularities of the caliber, provides the “programmed” information for the start, stop and return to zero functions of the chronograph. Sliding or cam chronographs are technically less complex, but no less reliable than column-wheel chronographs.

Small seconds
A seconds hand whose axis is not in the center of the dial. Most small seconds dials are located above the "6" on so-called "hunter" or "savonnette" watches, in which a 90° angle is formed by the crown, the center of the watch, and the axis of the seconds hand. Some movements are built in the so-called "Lépine" style: in these, the crown, the center of the dial and the axis of the small seconds hand (at "9 o'clock") all lie along the same line. Open pocket watches (i.e., Lépines with their crown at "12") have the small seconds at "6".

SMv (Movement)
A phrase printed in lowercase on the dial of non- Swiss wristwatches enclosing a movement that was made in Switzerland. The phrase "SMv"it is found, for example, on plagiarized copies. Usually printed in lowercase letters, the phrase can mislead an unwary buyer into misinterpreting and mistakenly assuming that the second word of the phrase is "done".

Springs of various types are used in watch movements. In addition to the balance spring and mainspring, other common types of springs include bridge springs and friction springs.

Spring balanced flat
Christian Huygens invented the flat balanced balance spring in 1675. The points of attachment of the spring to the balance staff (collet) and the balance spigot (pivot) are both in the same plane as the spring itself. Unlike Breguet overcoil balance springs, flat balance springs have the disadvantage that they do not develop absolutely concentrically as they expand and contract. This can have a negative effect on rate results. Modern mechanical movements usually have flat balance springs that have been given special deformation to counteract the above defects.

Spring Bar
A thin cylinder used to fasten a ”closed”" bracelet to the horns. The conical pin on each end of the spring bar is pressed outward by a cylindrical spring inside the spring bar. To attach a bracelet to a watch case, a spring bar is first inserted through each end of the strap, then the spring ends of each spring bar are pressed inward, and the spring bar is inserted between the "horns" on the case. When the pressure is released, the sprung ends snap into place inside the holes that have been drilled in the horns to fit them.

Stainless Steel
This popular alloy is a combination of steel, nickel and chromium, with a mixture of molybdenum or tungsten. Stainless steel does not rust, is very resistant and non-magnetic, but is relatively difficult to work with. Wristwatches with stainless steel cases have become increasingly popular in recent years. This also applies to luxury wristwatches with stainless steel cases.

A device that stops the progress of the movement and / or second hand so that the movements can be set with an accuracy per second. To do this, the user pulls the crown outward at the instant when the second hand reaches "12". When he or she hears a time signal, the crown is pushed inward and the second hand (along with the other hands of the clock) resumes its movement.

Striking work, striking mechanism
An additional feature in a watch that allows the watch to audibly announce the time with greater or lesser precision. A distinction should be made between watches that always automatically strike the time and those that only repeat (ring) when activated by pressing a button or moving the position of a slide.

Swiss lever escapement
An escapement for small timepieces in which the teeth of the escape wheel widens as the distance from the center of the wheel increases. The enlarged teeth distribute the lift given to the escape wheel and the pallets with its two pallet jewels (rubies). In addition to the Swiss anchor escapement, there are also English and Glashütte anchor escapements.

Swiss Made
Phrase, printed on the dial and / or imprinted in the movement, to identify the origin of a "Swiss wristwatch". According to the” Swiss Made Ordinance " of 27 May 1992, this phrase can only be used when the movement is Swiss and the assembly, coating and final quality checks have all been carried out in Switzerland. If a watch is to earn the right to carry the phrase " Swiss made” on the dial or movement, then at least 50% of the value of its components, excluding assembly costs, must derive from components that were manufactured in Switzerland. Non-Swiss manufacturers cannot use the phrase " Swiss made", but the assembly that has been carried out of Switzerland.

Tachymeter scale
A scale, printed on the dial of a chronograph, to aid in the calculation of average speeds. Tachymeter scales are generally calculated for a kilometer or a mile. The chronograph turns on at the starting point of a measured section, such as at the instant one's car passes a milepost on the side of the road, then turns off again when one's vehicle reaches the end of the measured mile. The chronograph second hand now points to the numbers on the speedometer that correspond to the average speed (in km / h) at which the measured stretch was crossed.

Unlike a bridge (or bar), a tap is screwed to the plate at only one of its two ends. The other end of the clock "floats" freely. Examples of taps include the balance cock, escape wheel cock, etc.

Telemetric scale
A scale on a chronograph to allow the wearer to read distances directly. The basis for the calculation is the difference between the speeds at which sound waves and light waves propagate through the air. For example, the distance between the wearer and a thunderstorm can be determined as follows: the chronograph turns on the instant a flash of light is seen, then stops when the corresponding thunder is heard. Depending on whether the rangefinder scale is calibrated in kilometers or miles, the chronograph second hand will indicate the number on the rangefinder scale that corresponds to the distance of the storm (in kilometers or miles) from the observer.

The parachute
Abraham-Louis Breguet (1747-1823) used this word to describe a shock-absorbing system he invented. To protect the delicate pivots of the balance rod, Breguet affixed the corresponding jewels to elastic steel arms.

Three-quarter plate
Unlike bridge movements, almost the entire gear train (except for the pallets, escape wheel, and balance) is supported under an additional plate. Three-quarter plates are used in American and British clocks, and especially in clocks made in Glashütte.

Invented by Abraham-Louis Breguet in 1795 and patented by its inventor in 1801, the tourbillon is a device that compensates for the error of the center of gravity that plagues the oscillating system (balance and spiral) of a mechanical watch. The French word "tourbillon" means "whirlwind". The device is suitably named because it encloses the entire oscillating and escapement system inside a rotating cage of the lowest possible weight. This cage completes a rotation around its axis during a particular unit of time (usually one minute). Thanks to its incessant rotation, a tourbillon compensates for the negative influences that the Earth's gravitational pull exerts on the scale when the watch is held upright, thus leading to corresponding improvements in rhythm accuracy. The tourbillon has no effect on frequency accuracy when the watch is held in a horizontal position. Wrist watches with a tourbillon mechanism were first made as competitors in time trial races in the 40s. Tourbillon wristwatches have been produced in small series since 1986.

In addition to the insignia that make up their names, many watch companies and ébauche manufacturers have also used and continue to use a so-called "trademark." This trademark, an easily recognizable logo, can be placed in various positions on a watch movement. It is often found on the front of the plate in a position normally covered by the dial. Manufacturers of movement blanks sometimes also place their trademarks (along with the caliber number) under the balance next to the balance cock. The cases generally bear the trademark on the inner surface of the back. Some manufacturers make their logo eternal on the outside of the watch, such as on the crown, back, and/or dial.

Tuning fork watch
An electronically tuning fork, oscillating at a frequency of 360 Hz, serves as a regulating organ. The best-known tuning fork watch is Bulova's "Accutron," which debuted in 1960.

Two-tone case
Watch case made of a combination of two different coloured metals, e.g. stainless steel and yellow gold, white gold and yellow gold or red gold and yellow gold. The yellow parts of some two-tone cases are simply gold-plated.

Visualization of equations
Due to the elliptical shape of the Earth's orbit around the sun and the inclination of the Earth's axis, the difference between the shortest and longest solar days of the year is 30 hours and 45 seconds. Keeping time based on real solar time with its ever-changing day lengths would be impractical in everyday life, so astronomers have defined "mean solar time". The length of an average solar day (86,400 seconds), which is indicated by all ordinary clocks and watches is calculated by averaging the lengths of all real solar days in a year. The visualization of the equation, invented at the end of the second century and since then has become extremely rare, shows the difference between average solar time and real solar time. Maximum deviations occur in mid-February (+14 min. 24 sec.) and early November (-16 min. 21 sec.). The lengths of the true and average solar days are identical four times a year (April 16, June 14, September 1, and December 25). Daily differences are programmed into the circumference of a kidney-shaped cam that each year completes a rotation around its axis. An elaborate mechanism "reads" this cam and transfers the information to an additional minute hand or a second pair of hands on the quadrant equation display.

Watch Winder
A mechanical device that gently winds self-winding watches when they are not worn. When a watch is stored in a watch magazine, it is slowly rotated around the rotor axis of the winder. This movement activates the charging mechanism. Watch chargers are especially useful for self-winding watches with many complications, because manually setting the watch can take a long time, depending on the number of complications. Thanks to storage in a watch magazine, self-winding watches can be worn at any time without a time-consuming setting and charging process. This also allows the owner to control the accuracy of the watch.

Quartz wristwatches Electronic wristwatches in which an oscillating quartz crystal serves as the regulating organ. The frequency of 32,768 Hz has become today's de facto standard. Because the speed regulating organ oscillates very rapidly, quartz watches are more accurate than mechanical watches. Quartz wristwatches were first commercialized in 1968.

Water-resistant wristwatches
The commonly seen phrase "water resistant to 30 meters" (3 bar or 3 atmospheres) is based on German industrial standard (DIN) No. 8310. According to this standard, a watch can carry this phrase on the dial if its case is resistant to sweat, splashing water and rain, and is water-resistant for at least 30 minutes when submerged to a depth of one meter . The additional information "30 m," "3 bar," or "3 atm" is not subject to regulation, but still indicates that watches displaying this information have passed the corresponding pressure tests to which their manufacturers have subjected them. However, it is not advisable to wear such watches while swimming and certainly not while scuba diving.

Winding commutator
Until the late 19th century, small keys were used to wind the springs and/or set the hands of many pocket watches. A watch with a modern crown winding system relies on a small crown to perform both of these tasks. The activity performed by the crown depends on how far it is pulled out of the case. The crown-winding system in common use today was invented by Jean Adrien Philippe, who received a patent for his invention on 7 September 1861. Philippe's idea consisted of a transmission wheel, which was installed on the winding stem in such a way that this wheel can rotate. This wheel is coupled via a gear cut with wolf's teeth to the manually adjustable pinion, which can be moved back and forth. The convenient backward 'idle' rotation of the crown was an improvement that improved the crown winding system. Today, this winding system is found on many millions of manual and self-winding watches.

World time display
Starting at zero degrees longitude (i.e. the Greenwich meridian), the time differs by one full hour every 15 degrees longitude. The world time zone system was first introduced by Canada and the United States in 1883. Germany began complying with this system in 1893. Watches with world time displays can show up to 24 time zones on a single dial. An additional mechanism supports the simultaneous display of time in more than one time zone. (A so-called 'heure universelle' can display the time in as many as 24 different zones). Watches with world time displays have been available since the 1930s and are particularly useful for people flying on long-haul flights or for business people having telephone conversations with colleagues in distant locations.

Wristwatch for the Blind
A wristwatch with a particularly sturdy dial and a crystal and bezel hinged so that the blind person can open the crystal, expose the dial, and "read" the position of the watch hands with his or her fingertips. The hour markers on watches for the blind are usually written in raised braille numerals.