The Hour Glass

AGE OF THE MOON
Time that has elapsed since the new moon. In some watches, the 29½ days of the lunar month are indicated on a lunar dial.

ANALOGUE DISPLAY
Indicates a passing of time by a marker (usually hands) on a scale on the dial.

ANTI-MAGNETIC
Used to describe a watch whose components are protected against magnetic fields.

APERTURE(OR WINDOW)
Small opening in the dial through which certain indications appear, such as the date, phases of the moon, etc. On some watches, the dial is replaced by a plate with two small windows showing the hours and minutes. Sometimes, there is a third aperture showing the seconds. These indications are given on what are called "jumping" discs for the hours (only moving once an hour) and "continuous" disc for the minutes and seconds (turning continuously). A demi-hunter watch case has a large opening in the center of the cover to see the dial.

ARABIC NUMERALS
1,2,3,4,5,6,7,8,9,0.

ASTRONOMICAL ALMANAC
Annual publication giving the positions of heavenly bodies.

AUTOMATIC WATCH
Watch whose mechanism is fitted with a device (rotor) that automatically winds the spring by using the force of gravity. The pocket-watch version dates from the third quarter of the 18th century.

BAGUETTE
Used in jewellery to describe a rectangular-cut diamond.

BALANCE
Device in a watch or clock which, by oscillating, regulates the movement of the train.

BALANCE-SPRING
Fine spiral-shaped spring which returns the balance to its position of equilibrium and guarantees isochronism; in other words, oscillations that are equal and independent of their amplitude.

BARREL
Cylindrical box containing the mainspring.

BARREL DRUM
Lateral wall of a barrel fitted with a hook to take the mainspring.

BASSINE
A watch case whose shape is somewhat like a basin.

BATTERY
Provides the energy needed to drive a quartz watch. A battery generally lasts one year or more, but there are now special batteries on the market that last ten or even twenty years. It is advisable to have the water-resistance of waterproof and divers' watches checked when the batteries are changed.

BELL
In the earliest repeater watches, a cup-shaped instrument struck by a small hammer. In alarm watches, it is a round disk with slightly curved edges.

BEZEL
Piece snapped onto the middle of a watch case to hold the glass or crystal in place. Sometimes, it has a rim between the glass ad the dial called a flanage.

BLUED STEEL
When a steel is heated, its surface is oxidized and becomes successively light yellow, straw-coloured, brown and finally blue [dark blue (290 degrees to 310 degrees); light blue (330 degrees)].

BRIDGE
A metal part in which one of the pivots of the moving parts of a watch usually turns.

BRUSH
To clean or polish with a brush.

BUCKLE (OR CLASP)
Device for joining the two ends of a strap or bracelet.

CABOCHON
Precious or non-precious stone, polished but uncut. An embossed ornament on a dial.

CALENDAR
Body of conventions adopted to reconcile the civil year with the tropical year and to determine its subdivisions: months, weeks and days. Religious festivals, the phases and age of the moon, and the seasons are frequently added.

CALIBRE
This term defines the shape and dimensions of a mechanical or quartz watch movement (see movement). As with watch cases, there are different types of watch and shape caliber: mechanical: rund, shaped, extra-thin, baguette, skeleton, manual or automatic, simple or complicated; quartz: simple or multifunctional.

CARAT
1) Standard to define the quality or fineness of gold. The fine-gold content of an alloy of 1 carat represents 1/24 of the weight of the alloy. For convenience, the fineness of gold may be expressed in thousandths rather than carats:
- 24 carats = 1,000 thousandths (1.000) [pure gold],
- 18 carat = 750 thousandths (0.750),
- 14 carats = 583 thousandths (0.583),
- 12 carats = 500 thousandths (0.500).
2) Unit of weight for precious stones equal to 0.205 gr. This unit has now been replaced by the metric carat, which is equal to 0.200 gr.

CASE
Cover on the bank of a watch. It can be hinged, screwed in, screwed down or snapped on.

CASE BACK
Container to hold the movement and protect it against dust, humidity and shocks. It is the focus of considerable aesthetic attention. Watch cases can be of many shapes: round, oval, rectangular, square, bassine, Empire, Directoire, lentille, knife-edge, etc A case is called "shaped" when it is not round. It can be flat or, to marry with the shape of the wrist, cambered.

CENTRE WHEEL AND PINION
The wheel, which is made of brass, is supported by a hardened steel pinion. The latter receives the energy from the barrel; at the same time it drives the cannon-pinion which is carried by the same staff. The center wheel meshes with the pinion of the third wheel.

CENTURY LEAP YEAR
Introduced when the Gregorian calendar was established in 1582. century leap years only occur every 400 years. Only years divisible by 400 are century leap years.

CERAMIC
A particularly hard, scratch-resistant, high-tech material sometimes used for the manufacture of watch cases.

CHAMPLEVE
A type of enamelling in which areas in a piece of metal are hollowed out and then filled with enamel.

CHRONOGRAPH (OR CHRONOSCOPE)
Watch with an additional direct drive seconds-hand that measures short periods of time. The seconds-hand on the first chronoscopes (1821) deposited a drop of ink to denote the end of the measured period of time; hence, the word chronograph (writer of time).

CHRONOMETER
A precision timekeeping instrument, with or without a chronograph system, that has obtained an official timing certificate.

CIVIL TIME
The time in force in the local time zone.

CLOISONNE
A type of enamelling in which patterns are made with thin strips of flat wire and the interstices filled with enamel paste.

CLOUS DE PARIS
Type of engraved decoration found on luxury watches.

COAXIAL
Having the same axis: coxial hour and minute hands move around the same axis.

COLUMN WHEEL
A wheel in top-quality chronoscopes that co-ordinates the phases of the chronograph function: starting, stopping and returning the direct-drive seconds-hand to zero. In more recent quality chronographs, this wheel is replaced by a system of levers.

COMPLICATED WATCHES
A mechanical watch giving indications other than the time in hours, minutes and seconds. The term "function" is used with quartz watches. The main complications are:
- ultra-thin movement,
- phases and age of the moon,
- simple (date) calendar,
- perpetual (date) calendar with or without automatic correction of century years that are not leap years,
- split-seconds chronograph,
- the tourbillon,
- minute-repeater.

COMPLICATION
Additional indication to those showing the time in hours, minutes and seconds. (see complicated watch).

CONTINUOUS TIME
Time which appears on a counter in the window of a dial; the time changes continuously.

CORRECTOR
A lever, usually accessible from the outside of a watch case, to bring a part back to a given position: eg. The date, day, phase of the moon, etc.

COUNTDOWN
Some watched indicate the time remaining in a predefined period. Example: a regatta watch.

COUNTER (or Totaliser)
Additional dial(s) on chronoscopes indicating the number of minutes (generally a maximum of 30) and hours (generally a maximum of 12) of measured periods of time.

DIAL
Surface bearing indications provided by the watch movement. It can be silvered, engine-turned (synonyms: guilloche, engraved), enameled, gilded, lacquered, or setr with precious stones. It can be plain, or have embossed, appliqué or painted numerals (Romanor Arabic) or hour markers, or a combination of both. Some dials bear a secret signature: the name of Cartier in minute letters, for example, replaced one Roman numeral, or Breguet engraved under the enamel and only visible in horizontal light. The numbers, hour makers or dots on luminous dials are coated with luminous salts.

DIGITAL DISPLAY
The indication of time by numbers on revolving discs displayed through windows, or in the form of liquid crystal numbers or light-emitting dioades.

DISC
Thin, flat circular plate that turns below the dial and shows the day, date, lunar phase, etc. through a window.
47. Display
Method of indicating hours, minutes and seconds mechanically, electrically or electronically. It can be analogue, digital or a combination of both.

DIVER'S WATCH
Watch designed for underwater diving. A genuine diver's watch has to undergo tests at a depth of at least 100 meters and meet strict criteria.

DOUBLE TIME-ZONE (OR DUAL TIME)
Watch which indicated the time in two time zones: the local time and the time in a second time-zone. Or, by extension, where the seconds dial is the same size as that of the hours and minutes.

ELECTRONIC WATCH
Watch with transistors.

ENAMEL
Vitreous substance, opaque or transparent, that is fired at a high temperature and used to decorate dials, cases, etc. Several successive firings take place in an oven heated up to 840 degrees centigrade. During the last firing, the date window is carved out by hand, if necessary, and the hour markers riveted on the dial. Some techniques date back to ancient China.

EOL (END-OF-LIFE) INDICATOR
Device to indicate that the battery in a quartz which is about to run out.

EPACT
The age of the moon on 1 January. It is used to set the dates of the new moons throughout the coming year.

EQUATION OF TIME
The difference between mean time and solar time caused by the eccentric orbit of the earth. On 16 April, 15 June, 2 September and 26 December, solar time and mean time coincide. Throughout the year, the equation of time varies by around 16 minutes. Exact formulas exist for calculating mean time from solar time, and these are adapted to watches fitted with this kind of complication.

EQUINOX
The time when the sun, by moving on the ecliptic, crosses the equator. The ecliptic is the trajectory that the sun follows on the celestial sphere in the course of a year. The spring equinox falls on 21 March, the autumn equinox on 21 September. On these two dates, day and night are of equal length.

ESCAPE WHEEL AND PINION
These two parts are made of hardened steel. The escape-pinion receives the energy from the fourth wheel while the escape-wheel itself transmits the energy to the pallets, which in turn drive the balance. For watches with a center seconds-hand, there are various solutions which might involve the use of two other wheels.

ESCAPEMENT
Mechanism fitted at the end of the gear-train, between the wheels and the regulatinf organ, and designed to:
- interrupt the movement of the wheels ar regular intervals,
- periodically distribute the energy to the balance.
The main kinds of watch escapements are:
- recoil escapement (verge or crown-wheel),
- dead-beat escapement (cylinder, virgule, double virgule),
- detached escapement (anchor, detent).
While the anchor escapement is by far the most common today, other kinds of escapements - detent and virgule, for example - are sometimes used for exceptional watches.

FINISHING
Series of adjustments and controls carried out in the final phase of manufacturing a watch.

FLINQUE
Engraving done by hand or by machine and composed of a large number of lines or curves intersecting regularly and covered with enamel. (See Guilloche, engine-turn).

FLY-BACK HAND
See split-seconds chronograph

FOLDING CLASP
Device invented by Louis Cartier for closing a bracelet. Patent no. 409 891: applied for on 12 February 1909, granted on 28 February 1910, and published on 5 March 1910.

FOURTH WHEEL AND PINION
The wheel, which is made of brass, is supported by a hardened steel pinion. The whole piece is driven by energy from the third wheel and pinion which it then transmits to the escape-wheel and pinion.

FREQUENCY
Defined by the number of oscillations per second. In quartz watches, the frequency is generally 32,768 oscillations per second. It is commonly expressed by the abbreviation Hz (Hertz).

G.M.T.
Abbreviation of Greenwich Meridien Time. GMT is a term sometimes used to describe a watch which indicates the time simultaneously in the world's different time-zones.

GLASS
Fragile, transparent, solid material produced bu fusing a siliceous sand with potash, soda, lime, alumina, lead, iron or boric acid, depending on the qualities required in the finishing product.

GOLDEN NUMBER
The number of any particular year during a 19-year cycle after which the new moons return to the same dates as the solar year.

GONG
Curved strip of hardened steel, or hollow or solid circular cylinder, struck by hammers in grand-strike watches and striking clocks, alarm clocks, or repeaters to produce a bell-like sound.

GOVERNOR
Fly or centrifugal device for slowing down the speed of strike-trains.

GREGORIAN CALENDAR
This is the calendar established by Pope Gregory XIII in 1582 to correct the Julian calendar. Pope Gregory dropped ten days from it, with 15 October following 4 October, so that the year would correspond more closely to the solar year and therefore to the seasons. This is the calendar still in use today.

GUILLOCHE
Engraved patterns of crossed or interlaced lines on metal. See flinque, engine-turn, engrave.

HALLMARK
Symbol stamped in metal to guarantee its origin and content of precious metal.

HAND
Indicator usually made of a light , thin piece of metal which moves around, or over, a graduated dial or scale. Watches generally have three hands to show the hours, minutes and seconds. Hands can have very different shapes: pear, Breguet, sword, skeleton, baton, arrow, etc. The seconds hand (sweep or direct drive) can be mounted at the center of the dial with the hour and minute hands, or on a small dial usually situated at 6 o'clock (small seconds). On a mechanical movement, the center seconds hand generally jump forwards five times a second; on a quartz movement, only once a second. Skeleton hands, so called because they are cut out in the middle, are called radium hands (synonym: luminescent, luminous) when the openings are filled with a luminous paste (radium salts in the past, tritium today).

HORNS
Variously shaped parts on a wristwatch that prolong the shape of the middle and are used for attaching the strap or bracelet.

HOUR MARKERS
Arabic numerals, Roman numerals or symbols placed around the dial to mark the hours. Tey can be painted, engraved, embossed, etc. on the dial plate. See dial.

HOUR-WHEEL
Made of brass, it completes one revolution in 12 hours and carries the hour hand.

INDEX
Device for regulating the daily rate of a watch by lengtheneing or shortening the active portion of the balance-spring. The index is a steel part with two arms: the shorter one carries the pins embracing the spring; the longer one, also called the tail or arrow, acts as a pointer, whose end moves over a graduated scale. This is marked F S (Fast-Slow), or A R (Avance-Retard) in French.

INVAR
Alloy of nickel and steel used for certain parts of watch movements, with a coefficient of expansion about 15 times lower than that of steel. Invented by Charles Edouard Guillaume (1861 - 1938).

JEWEL
A bearing, endstone or pallet of precious or semi-precious stone (ruby, sapphire or garnet) to reduce friction. Nowadays synthetic rubies are most commonly used (see Ruby).

JUMPING HOUR
Hour numerals that appear in an aperture of a dial. The charge of hour occurs as the result of a jumping action.

KARUSSEL
Device similar to the tourbillon, but what with the carriage drivern by the third wheel rather than the fourth. It is stronger than the tourbillon.

L.C.D.
Liquid Crystal Display. Liquid crystals, used to indicate the time in digital quartz watches and to represent the numbers and hands, are of organic substances. The glass plates which contain them are printed with numbers or metallic hands, whose segments are connected to an integrated circuit. When the current runs through these segments, they turn opaque and become visible.

LATITUDE
Angle measured from the equator and formed by the plane of the equator, the center of the earth and the place where the measurement is taken.

LEAP YEAR
Introduced by Julius Caesar into the Julian calendar in 45 BC, it already existed in some Egyptian and Babylonian calendars. A leap year has 366 days.

LOCAL TIME
Determined according to the local meridien.

LONGITUDE
Angle made by the meridian of a place, the center of the earth and the Greenwich meridian. The longitude of a place is determined by the difference between the local time at that place and the local time at the starting point. An exact knowledge of the longitude is essential for air and sea navigation.

LOOP
Attachment on a wristwatch case for fixing the wristlet.

LUG
Thim metal rod between the horns of a wristwatch for attaching the bracelet or strap.

LUMINESCCENCE
Having the power to emit rays of light. Tritium is a luminescent material deposited on numbers and hands so that the time can be read in the dark. It has replaced the salt-based substances of radium and phosphor.

MAINSPRING
A long strip of steel that regains its original shape after bending or compression. When wound, it provides the energy for mechanical watches.

MAINTENANCE
Work carried out to keep a watch in smooth running order. A few simple rules should be respected

- water-resistance should be checked every 2 or 3 years by a watch specialist,

- after an automatic watch has stopped, it should be rewound with the crown, never shaken,

- a watch should be taken off the wrist for winding to avoid any risk of breaking the winding stem,

- the crown should not be forced when the winding process is complete,

- the calendar should not be changed when the hands are between 10pm and 2am,

- the chronograph function should not be used in water,

- a waterproof watch and the bracelet should be rinsed in fresh water after swimming in the sea,

- a watch should never be opened, even out of curiousity,

- a mechanical watch should be regularly checked by a watch specialist,

- only a specialist should change a used battery in a quarts watch.

MANUFACTORY
In the Swiss watch industry, the term used for factories/workshops in which almost all the parts of a watch are made and assembled. They are distinct from finishing workshops (ateliers de terminage) where work is limited to assembling, timing, fitting of hands and finishing.

MEAN HOUR
One of the twenty-four parts into which a mean, or sidereal, day is divided. A mean hour is divided into sixty minutes.

MERIDIAN
Large imaginary circle passing through the earth's two poles. The meridian of a place is the circle passing through the two poles and that place. Greenwich meridian is zero. The hours counted from the Greenwich meridian represent universal time (UT or GMT).

MICRON
Metric unit of length, equivalent to one thousandth of a millimeter or one millionth of a meter and represented by the symbol µ. In the watch industry, tolerance are often expressed in microns.

MIDDLE
That part of the watch case in which the movement is fitted.

MINUTE WHEEL AND PINION
The wheel, which is made of brass, is supported by a hardened steel pinion. The whole piece reduces the movement between the cannon-pinion and the hour wheel. It carries the minute hand by means of the canon-pinion which completes one revolution in 60 minutes.

MINUTE-CIRCLE
Dots or strokes around the dial that mark the minutes.
98. Mirror Polish, Mirror Finish
Perfectly polished, without any spots or scratches.

MIXED DISPLAY
When a watch is analogue (with hands) for the hours and minutes, and digital (with numbers) for the other functions.

MOON PHASES
Different aspects of the moon during its cycle of approximately 29 and a half days. The four phases are:
- New moon,
- First quarter moon,
- Full moon,
- Last quarter moon.

MOVEMENT
A mechanism comprising all the main parts of a clock or watch. The clock or watch movement is distinct from the strike movement. In a mechanical movement, the energy produced by the spring is transmitted to the regulating organ (balance and balance-spring). The purpose of the escapement is to periodically distribute energy to this device. The spring can be wound manually or, thanks to a rotor turning freely with the movement of the wrist, automatically. Automatic watches can also be wound manually: for example, when the mechanism needs to be re-started after an extended period of non-use. In a quartz movement with an analogue display, the electrical energy is transmitted to the quartz in the form of vibrations. The integrates circuit reduces the frequency of the latter and transmits an impulse every second to the motor, which turns the hands.

MOVEMENT-BLANK
Incomplete watch movement. The modern movement-blank is a jeweled or non-jewelled watch movement, but without its regulating organs, mainspring, dial and hands.

NIELLO
Traditional type of decoration especially used on silver cases. A design is first engraved on a metal surface, then filled with niello - a compound of silver, copper, lead, antimony, ammoniac salt and sulphur - and fired at very high temperature. Finally, the surface is filed and polished.

OIL
Fatty, unctuous liquid of animal, vegetable or mineral origin. Watch oil must alter as little as possible and retain its lubricating properties. These are resistance to spreading, evaporation, oxidation, unctuousness, stability and viscosity. As oil oxidizes fairly rapidly, watches need to be periodically cleaned and lubricated by specialists.

OSCILLATION
Swing of the balance from one extreme position to another, then back to the starting point. One oscillation equals two vibrations. See Vibration.

OSCILLATOR
Device which, by maintaining periodic movements at a constant rhythm, measures time. In quartz models, this is the quartz resonator.

PAVED
Term used to describe a particular kind of decoration; for example, on dials in which precious stones are set next to each other without leaving any apparent space between them. Dials can be paved with brilliants, pearls, etc.

PERPETUAL CALENDAR
Device in a watch which automatically gives the exact date, taking into account the different numbers of days in the months and leap years. Some watches automatically include century years that are not leap years. A perpetual calendar can either indicate just the day of the month, or the date, day of the week, name of the month, and sometimes phases and age of the moon (time elapsed since the new moon).

PERPETUAL WATCH
Pocket watch with automatic winding. Name given by A.L Breguet.

PIN
Small cylindrical or slightly conical peg used for fixing, guiding and stopping.

PINION
Toothed wheel usually made of steel with a small number of leaves (teeth).

PIVOT
Extremities of the balance-staff or arbor that, in quality watches, turn in synthetic ruby bearings.

PLAIN DIAL
Dial with no numbers or hour markers.

PLATE
A piece supporting the various parts of the movement and the beidges. The bottom side of a plate is the dial side, the top side is the bridge side. In fine watches, bridges and plates can be engraved and polished, and, in the case of skeleton watches, pierced as well.

POLISHED
Surface made smooth and brilliant. Every part of a watch subject to a friction must ne polished. This mechanical process delays the inevitable build-up of rust.

POWER RESERVE
Device on certain automatic watches, or watches with a long running-time, indicating the time left before the mainspring needs rewinding.

PULSIMETER SCALE
Graduation on the dial of a chronograph for measuring heart beats.

PUSH-PIECE
Button on the watch case for activating chronograph functions (start, stop, return to zero). Chronographs can have one or two push-pieces.

QUADRENNIAL CALENDAR
Term used for a date mechanism which automatically calculates the length of the months, but which needs to be regulated every four hours for 29 February.

QUALITY MARK
Made on a watch movement as a guarantee that it has met all the criteria officially laid down in certain watch making regions: for example the Poincon de Geneve.

QUARTZ RESONATOR
Infinitely thin, u-shaped and made of synthetic quartz, it has an extremely accurate oscillation. It has two gold-plated ends oscillate when they come into contact with an electric current. The resonator is inserted into a metal capsule and vacuum-sealed. In a quartz watch, its functions like the sprung balance in a mechanical watch.

QUARTZ
Silicon Oxide. Also called rock-crystal.

RATING CERTIFICATE
Certificate of precision given to chronometers by qualified observatories - the best known in Switzerland are those in Meuchatel and Geneva - or by one of the C.O.S.C (Swiss Official Chronometer - Testing Institute) offices.

REPAIR
Mending, cleaning and lubricating a watch to put it into proper working order.

REPEATER
Watch with a mechanism that strikes on demand. There are several kinds of repeaters: quarter, half-quarter, five-minute and minute. In the earliest watches, the hammer struck a gong in the back of the case. In dumb repeaters, they strike noiselessly on another piece or directly on the case middle, and the vibrations are felt by the wearer. In the middle of the 18th century, many French watches were fitted with this kind of repeater.

RETROGRADE HANDS
On certain luxury watches and clocks, hands that move backwards to measure a new period of time.

ROMAN INDICTION
Known as the cycle of indiction, it is a 15-year period introduced by the Roman emperor Constantine as a fiscal term, a chronological date for the collection of taxes. The number of any particular year in the 15 year cycle.

ROMAN NUMERALS
I (1), V (5), X (10), L (50), C (100), D (500), M (1000). Watchmakers generally replace IV with III to make it balance visually with VIII. This also makes the same number of numerals between XII and VI on both sides of the dial.

ROTATING BEZEL
Graduated revolving ring on the upper part of the case. It can provide several kinds of indications and is mainly found on diver's watches.

ROTOR
Device for automatically winding a watch. In practice, a half-moon-shaped piece which turns freely in both directions and uses the force of gravity to wind the mainspring. Some rotors only turn in one direction or less than 360 degrees. Each time it moves, it advances the ratchet-wheel, which keeps the spring wound. In wristwatches, the rotor is generally made of brass, but as its weight is a determining factor in keeping the watch properly wound, other materials are also used: 18K, 21K, 24K gold or platinum, for example, in top quality watches.

RUBY
Very hard stone, usually synthetic, that prevents the wear of the gear-train parts. It is used to neutralize the end-play of the balance. It is also used in the pallets and on the plate. The greater the number of rubies, the better the quality of the watch.
132. Satin-Finished (or Brushed)
Used to describe a surface that has been brushed to tone down the shininess. The opposite of mirror-polished.

SCALE
Name for graduations on the dial of a watch used for making certain measurements. They can either be in the interior of the dial, on the rim, or engraved in the bezel. (see asthmometer scale, pulsimeter scale, tachometer scale, telemeter scale.)

SHOCK-RESISTENT (OR SHOCKPROOF)
Used to describe a watch fitted with a system to protect the balance-staff against shocks.

SIMPLE DATE
Ordinal number of each day in a month.

SIMPLIFIED CALENDAR
Term used for a date mechanism that needs to be corrected manually from one month to the next.

SKELETON MOVEMENT
Movement whose plate and bridges have been pierced and openworked to the extreme limit of the metal's resistance to reveal al the watch's components. Engraved and polished with matt or shiny finishes, these movements are veritable moving sculptures.

SMOOTH (DOWN, OFF)
Finishing operation on the movement consisting of beveling the edges of bars, and of polishing, satin-finishing and burnishing the flat surfaces of the plate and bars.

SOLAR CYCLE
Period of 28 years after which the same days of the week fall on the same dates of the month. Each year is numbered to indicate its position in the cycle.

SOLSTICE
Time when the sun is at its greatest distance from the celestial equator and begins to return towards it. In summer about 22 June; in winter about 22 December.

SPLIT-SECONDS CHRONOGRAPH
Chronograph with two superimposed center seconds hands - the ordinary chronograph hand and the fly-back hand - for measuring periods of time that are of different lengths but start simultaneously.

STEPPING MOTOR
In quartz analogue watches, the stepping motor transforms the electrical impulses that it receives from the circuit into movement, thereby activating the hands through the gear-train.

STRIKE-HAMMER
Watch, or clock part that strikes a bell or gong.

STRIKING-MECHANISM, STRIKING-WORK
Automatic or hand operated mechanism that strikes the hours, etc., or rings an alarm bell at a pre-set time. There are several different kinds of striking-work:
- hour-strike,
- ting-tang (quarter repeater),
- five-minute repeater,
- minute-repeater,
- grande sonnerie or grande strike,
- chimes (like a carillon or the pearls of cathedral bells),
- alarm,
- locking-plate,
- striking rack.

SUMMER TIME (OR DAYLIGHT SAVING TIME)
Introduced to give people one or two extra hours of daylight in summer.

SUNDAY LETTER
A letter in the ecclesiastical calendar used to designate Sundays throughout the year.

SUNRISE AND SUNSET
Days and nights vary in length with the seasons and latitude. Some complicated watches indicate these.

TACHOMETER
Instrument for measuring speed. In watchmaking, a timer or chronograph with a graduated dial on which speeds can be read off in kilometers per hour or some other unit.

TELEMETER SCALE
Graduations on the dial of a chronograph for measuring distances based on the speed of sound (333.3 metres/seconds).

TESTS
Watches are tested for their resistance to water, high and low temperatures, corrosion, magnetism, shock, etc.

THIRD WHEEL AND PINION
The wheel, which is made of brass, is supported by a hardened steel pinion. The whole piece is driven by energy from the center-wheel and pinion which it then transmits to the fourth wheel and pinion.

TIME ZONE
To standardize the time in every country, the world is divided into 24 time zones. They start at 0 with the prime, or Greenwich, meridian. Every point in the same time zone has the same legal time.

TIMEKEEPERS
Highly accurate instruments for measuring and keeping time.

TIMING (OR RATING)
Series of operations to put a watch into proper running order. These are based on observations and corrections of a watch in different positions at different temperatures. There are various grades of timing, according to the precision required:
- ordinary timing,
- reglage plat-pendu 30 secondes (French term for ordinary timing in which the difference between the D.U and the P.U positions does not exceed 30 seconds)
- timing in positions,
- timing at various temperatures,
- precision timing,
- high-precision timing.

TITANIUM
Blackish metal used in making certain kinds of steel. It is extremely resistant to corrosion and has special characteristics. Sometimes used in the manufacture of watch cases.

TONGUE OR TANG
Moveable metallic piece in a buckle which penetrates the hole in a leather strap.

TONNEAU
Barrel-shaped watch case. Louis Cartier began to use this design for some of his bracelet watches in 1906.

TOURBILLON
A watch movement invented by A-L Breguet to eliminate errors of rate due to the earth's gravity. It consists of a mobile cage that carries the regulating organ (balance and balance-spring) and the escapement. The escape pinion turns around the fixed fourth wheel and pinion. The rotation of the cage on its axis (once every 60 seconds) compensates and thus eliminates the effects caused by friction and those caused by parts that are incorrectly balanced or affected by the earth's gravitational pull when the watch is in a vertical position.

TRANSISTOR
Semi-conductor device acting as an amplifier, oscillator, modulator and detector of electric currents.

TRITIUM COATING
A radioluminescent material containing tritium deposited on parts of the display in timekeeping instruments so they can be read in the dark.

TROPICAL YEAR
Period of time that separates two summer or winter solstices.

TRUE HOUR
One of the twenty-four parts into which a true solar day is divided.

UNIVERSAL TIME
Name given to the first watches that indicated the time in the world's major cities. The names of the cities are engraved to the bezel or on the dial. The name is still in use.

VAGUES (OR COTES) DE GENEVE
Decoration of undulating lines reminiscent of waves and frequently used for the embellishment of quality movements.

VIBRATION
Movement of an oscillated body between two extreme positions. Two vibrations equal one oscillation. As a rule, a watch balance makes 5 vibrations a second, or 18000 an hour. However, there are also very sophisticated watch balances with even hugher counts, up to 36000 an hour, or more. The higher the number of vibrations, the smoother the watch will run.

WATCH COMPONENTS
Parts - springs, winding-stems, balance-staffs etc. - used for repairing or manufacturing watches.

WATCH
Portable timepiece that runs in any position. A watch comprises four essential parts: the movement, the case, the dial and the hands. There are very many types of watches. These are named according to:
- how they are worn: pocket watch, wristwatch, jewel-watch, brooch-watch, pendant-watch, etc.
- shape: round, oval, tonneau, rectangular, square, baguette, etc.
- purpose: sports, diving, sailing, flying, etc.
- Type of escapement: lever, cylinder, detent, tourbillon, verge, etc.
- Certain construction features: automaton, dustproof, handless, automatic, calendar, complicated, electric, waterproof, perpetual, etc.

WATCH GLASS (OR CRYSTAL)
Piece of natural or synthetic glass fitted into the bezel to protect the dial and hands. Nowadays, watches are fitted with harderned and therefore highly resistant mineral glass, or with synthetic saphhire crystal that is almost totally scratch-resistant. On many high value watches, the case backs are replaced by a sapphire crystal through which the mechanism is visible. Other synthetic materials used have included celluloid (soft and inflammable), rhodoid, and now mainly Plexiglas (synthetic resin, which is harder and non-inflammable).

WATERPROOF (OR WATER-RESISTANT) WATCH
Watch whose case is fitted with joints to protect the movement from water, but is not designed to remain submerged for any length in time. Without any specific indication to the contrary, this kind of watch is water-resistant to the pressure exerted at a depth of at least 20 metres. It has to meet strict criteria.

WATER-RESISTANT JOINT
In water-resistant watches, joints are indispensable for hermetically sealing various parts of the case, like the back, crown, pushpieces and crystak. Joints can be made of rubber, neoprene or plastic materials.

WHEEL
Circular part revolving round an axis to transmit power or motion. A toothed wheel or gear-wheel is riveted to its pinion.

WINDING
Action of tightening the main-spring of a watch. A watch can be wound manually or automatically.

WINDING CROWN
Variously shaped buttons, knurled or fluted, for winding the watch or setting the hands. On early wristwatches, the time was set by pressing a push-piece or button and turning the crown.

ZODIAC
The ecliptic plane was divided by Babylonian astronomers into 360 degrees, measured from the first point in Aries in an easternly direction. The zodiac was divided by the Babylonians into 12 parts of 30 degrees, each bearing the name of a constellation. The sun is said to be in a certain sign of the zodiac when the constellation is diametrically opposite the earth.
- O degree to 30 degrees Aries 21/03 - 20/04
- 30 degrees to 60 degrees Taurus 20/04 - 21/05
- 60 degrees to 90 degrees Gemini 21/05 - 21/06
- 90 degrees to 120 degrees Cancer 21/06 - 23/07
- 120 degrees to 150 degrees Leo 23/07 - 23/08
- 150 degrees to 180 degrees Virgo 23/08 - 23/09
- 180 degrees to 210 degrees Libra 23/09 - 23/10
- 210 degrees to 240 degrees Scorpio 23/10 - 22/11
- 240 degrees - 270 degrees Sagittarius 22/11 - 22/12
- 270 degrees - 300 degrees Capricorn 22/12 - 21/01
- 300 degrees - 330 degrees Aquarius 21/01 - 22/02
- 330 degrees to 360 degrees Pisces 22/02 - 21/03