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Tim Temple watches - Watch glossary
Category: General technical and industrial > Watches
Date & country: 08/11/2007, UK
Words: 241

Great Wheel
The first wheel of the train, integral with the fusee-cone (if present) or with the going barrel if no fusee is fitted.

An alloy of tin and copper, which in the late 1800s replaced brass as the preferred base metal for watch-cases.   A gunmetal case does not necessarily betoken a cheap or low-grade watch;  many complicated movements of the period 1890-1920, often of high quality and sophistication, were so fitted.

(often abbreviated to ‘hack`)   A watch with a small lever under the dial which thrusts a wire hook between the teeth of the escape-wheel or fourth wheel, thus stopping the movement.   This device became popular soon after 1800 (concurrently with the increasing use of the seconds dial), doubtless wi

A type of escapement which followed the spring-detent pattern in using a pallet mounted directly on the escape-wheel to give impulse to the balance but which retained a separate element (a variant of the lever) for the locking function.

A variant of the hunter in which the front cover has a small crystal let into it so that the hands can be seen without opening the cover.   On early examples (c. 1800-1830) there may be a duplicate chapter-ring painted near the centre of the dial so that it can be seen through this panel;  later thi

A style of calibre in which the balance, escape-wheel and fourth wheel are located by individual bridges, the bottom plate being cut away to reveal them.

(Hamilton Watch Co.)   U.S. manufacturer, founded at Lancaster (Pa.) as Adams & Perry in 1874;  the Hamilton name dates from 1892.   The firm specialised in railroad watches and other products of high quality, and was prominent in the application of Elinvar (an alloy virtually unaffected by temperat

Harrison, John
(1693-1776) English craftsman, inventor of the first practical marine chronometer.   Son of a village carpenter, Harrison taught himself mathematics and horology.   In his early 20s he built several innovative clocks constructed almost entirely of wood.   He became interested in the £20,000 prize ap

A watch that runs for seven or eight days at one winding (the Greek word means ‘group of seven` and hence ‘week`). Hebdomas watches, introduced in Switzerland in about 1890, used an oversized mainspring whose barrel spanned the entire width of the movement, cutting off access to the balance and regu

Helical Spring
A balance-spring whose coils lie one above the other in a cylindrical configuration, in contrast to the usual flat or spiral pattern.   John Arnold used helical springs in his chronometers.

Hooke, Robert
(1635-1703) English scientist, pioneer in the use of the microscope.   He regarded himself as the discoverer of the balance-spring (bitterly disputing precedence with Huygens) and undoubtedly formulated its theoretical basis in the Latin phrase Ut tensio sic vis (‘the power depends on the tension`);

Horizontal Escapement
An early name for the cylinder escapement, prompted by the fact that the escape-wheel lies in the same plane as the train wheels whereas in the verge it is at a right-angle to them, standing upright when they are horizontal.

Stag horn was a popular material, cheap but decorative, for covering base-metal watch cases in the late 18th century. It is slightly translucent and has an attractively mottled pattern ranging from reddish-brown to cream.

The science of time measurement, from Greek hora ‘point in time` and logos ‘word, speech, process of reasoning`. Strictly speaking a horologist is an abstract researcher, not a practical constructor of timekeepers, although the two aspects have often overlapped in one person's achievement (Berthoud,

Howard, Edward
(1813-1904) U.S. watchmaker, associated with Aaron Dennison in the early days of what afterwards became Waltham. In 1858 Howard founded his own firm, using Dennison's original Roxbury (Mass.) factory.   Howard retired in 1882, but watches of restrained design and excellent quality were made independ

Hunter-Hunting Case
British and American terms, respectively, for a watch whose dial is completely covered by a spring-loaded hinged panel which must be released (usually by pressing a button) to view the hands.

Huygens, Christiaan
(1629-1695)   Dutch diplomat, musician (prolific composer for the lute) and horological theorist;  first to achieve a practical application of the pendulum (in clocks built to his design by Salomon Coster, c. 1656);  probable discoverer of the balance-spring, although Robert Hooke bitterly disputed

The moment of contact between the escapement and the balance which allows the power of the mainspring to be momentarily fed through to the balance, so that it keeps moving instead of drifting to a halt.

Impulse Pin
In a lever escapement, a pin made of ruby, mounted on a steel disc called the roller which is fitted to and concentric with the balance-staff.  This pin engages in the fork of a lever and receives impulses from it, thus keeping the balance moving.   Also called roller jewel.

Isochronous, Isochronism
A oscillating object such as a balance-spring is said to be isochronous, or to show isochronism, when it takes exactly the same length of time to accomplish each swing or arc irrespective of the distance covered;  thus it beats at the same pace whether it is being driven strongly or weakly.     The

Japy, Frédéric
(1749-1813) Swiss watchmaker whose extensive application of machinery to the manufacture of watch movements, from 1776 onwards, laid the foundation for the vast expansion of the Swiss industry in the nineteenth century.

A piece of ruby or (less commonly) sapphire or aquamarine, used as a substitute for steel where great resistance to wear is needed — most usually as a bearing in which the pivot of a wheel rotates.   The pallets of a lever escapement are also jewelled.   The technique of making jewels was patented b

Jump Second-Hour
A hand or other indicator (e.g. a digital display) which moves from one step to the next in jerks rather than continuously.

A slow-turning variety of tourbillon devised by Bonniksen of Coventry (U.K.) in 1894.

Until the 1820s virtually all watches depended on a separate key, fitting over a square-ended shaft, for both winding the spring and setting the hands.   (The exceptions were perpetuelles, the idea of which was known in the 18th century.) English watches were usually wound from the back and set by p

Lancashire Gauge
An early system of classifying and standardizing the sizes of watch movements, developed in Victorian times by the makers of Liverpool and the watchmaking centres round about such as Ormskirk.   It was based on units of one-thirtieth of an inch (0.033');  size 1 represented 1.167', size 2 1.2', and

Lancashire Watch Co.
English manufacturer, founded at Prescot (near Liverpool) in 1888 to introduce American methods of mass-production. Lancashire movements are often false fusees, retaining such traditional features as gilt plates, engraved cocks and hand-lettered enamel dials;  they were frequently supplied for badge

Le Roy, Pierre
(1717-1785) French horologist, inventor of the duplex and pivoted detent escapements;  built a chronometer in 1766, incorporating a system of temperature-compensation based on the movement of mercury in thermometric tubes, which might have equalled Harrison's achievements and certainly depended on m

The word ‘teeth`, applied to the projections on a gear-wheel, is replaced by ‘leaves` when speaking of a pinion.

Lépine Calibre
From about 1760 onwards, J. A. Lépine broke away from the hitherto dominant full-plate layout by introducing a free-standing going barrel (with neither plate nor bridge to support its outer end) and by mounting the balance cock on a level with the outer face of this barrel rather than projecting bey

Lépine, Jean Antoine
(1720-1813) French clock- and watchmaker, associated with Voltaire and favoured successively by the Bourbons and Napoleon;  early champion of the cylinder escapement and inventor of the virgule;  influential in reducing the thickness of watch movements by devising the Lépine calibre and dispensing w

Lever Escapement
The standard escapement for domestic watches from about 1840 in Britain and the U.S.A. (1890 in Switzerland) until the rise of the quartz watch;  it is still used in mechanical movements today.   The ‘lever` is a pivoted bar to which is attached an arm carrying two pallets, which alternately engage

Lever Setting
A method of setting the hands by means of a lever (normally concealed under the bezel) which when pulled outward operates a clutch which releases the motion-work from the train, so that the hands can be pushed round manually without disturbing the running of the watch.  This arrangement is found on

In the lever escapement, the configuration of the mating faces of the pallets and escape-wheel teeth which ensures that impulse is given with just the right degree of interference between their respective paths.   In the English or side lever, the teeth come to a sharp point and the pallets are sole

A unit of measurement developed in France and still used in the Swiss industry for gauging the diameter of a movement. One ligne (1```) is one-twelfth of a pre-metric French inch, or 2.256mm.

English port and manufacturing town.   Liverpool grew rapidly in the second half of the eighteenth century under the twin influences of industrialisation and the growth of transatlantic traffic.   Its vigorous watchmaking industry dates from this time.   In the following century Liverpool makers dev

Liverpool Window
A very large (up to 5mm), clear and almost colourless jewel, secured by two or three screws.   Such jewels were common in Liverpool watches from about 1820 to 1860.

The stage in the cycle of an escapement when the train is immobilised by the controller.

Position on the earth's surface eastward or westward of an agreed starting-point (meridian â€` usually the meridian-line at Greenwich Observatory, London), expressed in degrees, minutes and seconds.   Identifying a ship's longitude when out of sight of known landmarks was a lasting problem, beset by s

Lunette Glass
A type of glass (crystal) common in the 19th century, with a two-stage curvature, steep near the bezel but much flatter over the greater part of the surface.   This style replaced the bullseye glass.

The coiled spring of tempered steel which provides the power source for all watches (except those with battery- or solar-powered movements) and most clocks.   References to spring-driven clocks in Italian documents of the 15th century suggest that Italy, rather than Germany, may have been the home o

Maintaining Power
An auxiliary power source to keep a clock or watch running whilst it is being wound.   John Harrison first applied it to watches;  his system was embodied within the cone of the fusee and was gradually adopted (not necessarily on the most luxurious or expensive watches) as the 19th century progresse

Massey, Edward
(1772-1852) English watchmaker whose variants of the lever escapement, devised in the second decade of the 19th century, gained considerable currency until about 1850.   There were five types, all adopting a drum-shaped roller with the impulse-pin alongside it rather than the usual flat disc with th

Mean Time
A scale of time-measurement in which the units â€` second, minute, hour etc. â€` are of the same length throughout the year.   It is easily forgotten nowadays that this is not true of the sun's time, by which the length of a 24-hour period shows a variation of up to 30 minutes 46 seconds if measured by

Merlin, Joseph
(1735-1803) Belgian inventor of (amongst other things) a timekeeper wound by the opening and shutting of a room door, as well a wheelchair (sometimes called ‘Merlin chair` after him in the English of 200 years ago).  

Montgomery Dial
A dial with each individual minute numbered in arabic figures;  an American fashion of the period 1890-1920.

French for ‘watch`.   Both the French (from the verb montrer, ‘to show`) and the English names seem to contain the idea of something observed or offered for observation.   This may be connected with the fact that early public clocks seem to have been designed more for the ear than the eye, since the

Moon Hand
See Breguet hand.

Motion Work
The gearing, usually consisting of two wheels and a pinion, fitted between the front plate and the dial of a watch to link the hands to the train and to each other.   The motion wheels are loosely fitted (one being located by the cannon pinion and the other by a peg on the plate), and if the dial is

The correct name for the ‘works` of a watch.   Vast numbers of movements survive without their cases, which have presumably been removed for melting down;  these often remain in working order and can provide an easy means for the budget-conscious collector to obtain examples of scarce escapement typ

Mudge, Thomas
(1715-1793) English clock- and watchmaker, pupil of George Graham;  inventor of the lever escapement (in a watch made for the consort of the future King George III, c. 1757);  early contributor to the development of the chronometer; allegedly the first to apply jewels to pallets.

The link between music and horology might well form the subject of an extended thesis.   Hans Leo Hassler or Hasler (1564-1612) of Nuremberg, allegedly the first maker of a chiming watch, was also a distinguished composer who anticipated Schütz in introducing the Venetian choral style to Germany;  h

Norton, Eardley
(fl. 1760-1794)  Fashionable London maker patronised by King George III and Catherine of Russia;   probably the victim of more piracies than any other watchmaker in history, Breguet not excepted.   These are generally Swiss and some of them attempt to follow English design conventions such as the si

(French:  ‘onion`)   A French watch of the late 1600s whose very deep calibre gave it a bulbous shape, the source of the name.   There is generally only one hand;  the arbor of this is hollow and the winding-square projects through it in the centre of the dial.

Oil Sink
A saucer-shaped indentation surrounding the hole where a pivot comes through the plate.   This serves to retain oil and prevent it from spreading uselessly over the surface of the plate.   Oil-sinks were invented in about 1720 by Henry Sully, an Englishman working in Paris.

Town in Lancashire, north-west England, a few miles from Liverpool, where there was a substantial colony of watchmakers in the early 19th century â€` an English equivalent of Le Locle or Chaux-de-Fonds in Switzerland.   The place was particularly noted for a variant of Pierre Debaufre's escapement.

A method of improving the isochronous characteristics of a hairspring by bending its outermost coil inwards and upwards so that it ends and is anchored well within the circumference of the spring.   Breguet invented it and it is often called after him;  see spiral Breguet.

Pair Case
The usual style of case on British watches from about 1680 to 1820 (also used in Europe, but less exclusively).   The movement is housed in a very plain case which incorporates the crystal and pendant and (in Britain) is pierced at the back by the winding-hole;  this is fitted into a completely sepa

A tongue or cam mounted on the balance-staff, or (in certain escapements like the lever escapement and some types of detent) on a component interacting with it, and designed to engage with the escape-wheel for the purpose of either receiving impulse or performing the locking function.   There are us

An arrangement for insulating the fragile balance-staff against lateral shocks by mounting each of its pivots in a springy steel arm; invented by Breguet.   Click here for an example.

A flat spring which allows a rotating and an oscillating component (e.g. escape-wheel and balance) to pass each other with virtually no resistance in one direction but which obstructs the wheel on the return swing of the balance.   This is applied in the spring detent escapement, where the effect is

The shaft which protrudes from one side of a watch-case, ending in a cross-piece on which the bow is hinged.

Pendulum Watch
This expression is often found in advertisements and other descriptions of the late 17th century â€` too often to be explained simply as a reference to the false pendulum.   I suspect that, because the pendulum and the balance-spring served the same purpose, appeared at much the same time and were per

A watch that is wound automatically and continuously by the motions of a weight that swings round under the influence of gravity as the wearer's movements put the watch into different positions.   The principle was known in the eighteenth century.

Perron Escapement
A variety of lever escapement in which the pallets are replaced on the lever by pins and the escape-wheel teeth are shaped like wedges with the broad end outwards;  invented by Perron of Geneva in 1798, applied by G. F. Roskopf in his inexpensive ‘People's Watches` from 1867 onwards, and still found

A brass post separating the two plates of a full-, half- or three-quarter-plate movement.   Until about 1790 pillars were of various ornamental forms, usually rectangular or polygonal in cross-section;  afterwards they were cylindrical.

Pin Setting
Essentially the same as lever setting, with the difference that a push-pin is used to disengage the hands from the train so that they can be set without stopping the watch.

Pinchbeck, Christopher
(1670-1732)   English clock- and watchmaker, inventor of the gold-like alloy (a form of brass) which bears his name.

A small wheel mounted on the same arbor as a larger one and generally used to transmit the drive between that wheel and another.   Pinions are usually of steel and have six or eight ‘leaves`, as their teeth are called.

A device invented by Huygens for increasing the arc (and therefore the momentum) of the balance-wheel in a verge escapement.   The balance-staff carries a pinion which engages with a vertical wheel of contrate form;  the pallets are on the arbor of this rather than on the balance-staff itself.

The narrow tip of an arbor, rotating in a hole pierced in one of the plates (usually, since the late 1800s, with a jewel by way of bearing).  The steel used for arbors is quite brittle and pivots often break, especially at the outer end of the balance-staff.

Pivoted Detent
A type of escapement invented by Pierre le Roy, in which pallets mounted on the rim of the balance-wheel itself interact with the four long spokes of a rotating component (the detent) to achieve locking.

A panel of brass or (in more recent times) nickel, pierced with a number of holes to receive the pivots of a watch's moving parts.   Until the late 1700s there were two plates, separated by pillars, and most of the movement was sandwiched between them;  then came the Lépine calibre which led directl

Poker Hand
The minute-hand of a typical 18th-century English watch, slim and tapered, with a touch of ornament near each end; used in conjunction with a beetle hour hand.

An incorrect but common term applied to dials which are actually enamel.

Position Error
Variation in a watch's rate when it is held or suspended in different positions.   This is most often encountered in unrestored movements which (for example) run badly or not at all when placed upright or dial downwards, usually because the the balance-staff pivots are worn or the table of the cock

A small bracket, screwed to one of the plates, to support one end of an arbor.   Bridge, cock and potence are overlapping terms;  essentially they all mean the same thing, but cock is generally used only of the bracket over the balance-wheel, while bridge is preferred where the component is attached

Private Label
An American watch made by one of the large factories for a retailer, whose name appears on the movement instead of that of the maker.   Private-label watches have a following of their own amongst collectors.

An early form of keyless winding, using a plunger to operate a lever mounted on the bottom plate, acting on a ratchet, to turn the fusee cone or going barrel.   Unlike stem-winding, this lent itself readily to use in conjunction with a fusee, and so it had a certain currency in 19th-century Britain,

Puritan Watch
A mid-seventeenth-century English watch of very plain design, precursor of the classic pocket-watch as we still know it with white enamel dial and minimally decorated silver or gold case.   So called in allusion to the austere religious fundamentalists popularly so called, who were socially and poli

Quare, Daniel
(1649-1724)   English clock- and watchmaker, inventor of the repeater.   Together with Tompion, Quare deserves a large share of the credit for establishing England as the world's leader in horological matters throughout the 18th century.

Quarter Repeater
A repeater which indicates the last completed quarter-hour by striking the hour itself on one gong followed by one, two or three blows, each representing fifteen minutes, on a second.

(French) Four.   Old Swiss watches are often stamped quatre rubis (four jewels);  this is the absolute minimum number in a respectable watch, indicating that only the balance-staff is jewelled.

An escapement patented by Peter Litherland of Liverpool in 1791, using a principle outlined by Jean Hautefeuille in the 1720s.   It resembles a side lever, but instead of a fork the inner end of the lever carries a toothed quadrant which engages with a pinion on the balance-staff.   It had a certain

Railroad Watch
A watch designed for use by railway officers — not necessarily actually applied as such, but designed and adjusted to meet the standards that this application would require.   Watches marked ‘Chemin de Fer` or ‘Railway Time Keeper` begin to appear in Europe in about 1850, but the true railroad watch

Ramsay. David
(?-1654)   Scottish clock- and watchmaker, trained in France and appointed clockmaker to King James I in 1613.   He was the first Master of the Clockmakers' Company on its incorporation in 1631.   He was a prolific inventor in several branches of trade and engineering, from mining to textile-dyeing.

(1)   The deviation of a timekeeper from strict accuracy, expressed as an average.   Thus an early chronometer might be said to have a [gaining or losing] rate of (say) five seconds a week, and this would be taken as read in judging its performance thereafter;  provided it never deviated materially

In some escapements, the slight reverse motion of the escape-wheel when it meets the pallet responsible for locking. Recoil is in theory undesirable, since it hampers the free movement of the controller;  but sometimes it is allowed for and indeed turned to advantage in making the locking process se

A device for altering the effective length of a balance-spring by sliding the curb-pins, which lightly restrain it close to its outer end, back and forth along its length.   The earliest balance-spring watches used the Barrow regulator, which incorporated a worm-drive.   This was followed in about 1

This word, stamped on the cuvette of a Swiss watch, often constitutes a bitter disappointment to collectors who believe they have found a watch fitted with the sophisticated item described in the next entry.  In fact, it is merely French for stem-winding.

An arrangement, invented by John Harrison and found only in chronometers and first-class watches, for preventing the declining power of the mainspring as it unwinds from creating a loss of pace at the balance.   (The fusee cannot do this precisely enough.)   The remontoire consists of a small slave

A clock or watch that chimes the last completed hour (and often the quarter-hours as well) when a plunger or slider is operated.   The necessary mechanism is usually housed between the dial and the front plate, so that it adds very little to the bulk of the watch;  this compactness is possible becau

Reversing Pinion
A device which enables the hands of a key-set or stem-set watch to be moved without disturbing its running.   (Moving the hands on a watch without this provision can produce some very odd consequences, especially if they are moved anti-clockwise;  a lever watch may actually run backwards in this sit

A polished steel disc mounted on the balance-staff of a lever watch.   The side that faces towards the lever (when the watch is at rest) has a sector cut out of it, and just inboard of this stands the impulse-pin (a peg made of ruby), which engages in the fork of the lever.

Roskopf, G. F.
(1813-1889)   German watchmaker who settled in Chaux-de-Fonds, Switzerland, and set up a factory to produce a watch of consistently sound quality at a lower price than had previously been possible.   He did this by applying American production-line methods and by simplifying the train, which had onl

(French) Ruby.   In the inscriptions on the cuvettes of French and Swiss watches, the jewels tend to be described as rubis rather than by the more general word joyeaux (‘jewels`).

The mineral most commonly used for jewels.   Sapphire, amethyst and aquamarine have also been applied.

Safety Pinion
Alternative (mainly U.S.) name for reversing pinion.

Safety Roller
A second roller, mounted closer to the balance-wheel than the roller which carries the impulse-pin, and with a curved notch on one side into which the dart fits.

Savage Escapement
A variant of the lever escapement with two pins on the roller (for locking) and a third on the lever itself, engaging in a deeper than usual notch in the roller, for impulse;  invented by George Savage, a Yorkshire watchmaker who eventually settled in Canada (?-1855).