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A Brief Glossary of Technical Terms (continued)

GERMANY
(incl. AUSTRIA)

According to 16th-century witnesses, Peter Henlein of Nuremberg was the first to make portable spring-driven
timepieces, beginning in about 1510.   Early German movements were often of iron rather than brass and included
striking mechanisms and other complicated work.   The Thirty Years' War undermined the development of the industry
and German watches came to follow French stylistic trends, although some individual features remained, notably the
practice of applying an elaborately pierced and engraved latticework over the bottom plate.   Among the outstanding
craftsmen of the 17th century were the Buschmann family of Augsburg, whose activity continued for nearly 200 years.
The 18th century was notable for some very large and elaborate watches with alarum mechanisms;  at the same period
Austria (especially Vienna) developed a tradition of its own showing strong English influence.   After 1800 the Swiss
industry attracted much talent and craftsmanship from Germany, as from everywhere else;  thus G. F. Roskopf based his
successful factory for a low-priced but well-made watch in the Franco-Swiss border town of Chaux-de-Fonds.   In 1861,
however, the brothers E. and X. Junghans set up their clock and watch factory at Schramberg in the Black Forest, an
area which had fostered a cottage industry since the early 1700s;  the firm of Junghans still exists, as does that of
Adolf Lange (founded at Glashütte, near Dresden, in 1845).  

GOING BARREL

A mainspring barrel which drives the train directly rather than through a fusee.   Going barrels are occasionally found as
early as 1700 but were first put into regular use by Lépine and his followers from about 1780.

GRADE-NAME

A borrowed or fabricated name engraved or stamped on a movement as if it were the manufacturer's signature, not with
any intent to deceive but purely to indicate the quality of the watch as the maker sees it.   The dawn of the practice can
be seen in Britain soon after 1800;  thus James McCabe and M. I. Tobias marked their lesser watches ‘Beatson’ and
‘William Robinson’ respectively.   However, the system is chiefly American.   Grade-names were chosen to honour
figures from history, to flatter investors and company directors or (as in Waltham's ‘Appleton Tracy’) to document the
manufacturer's own ancestry (see United States for some examples).   They distinguish such features as the number of
jewels or the amount of testing and adjustment bestowed on the movement at the factory;  sometimes the grade
determines whether the watch is eligible for the coveted railroad designation.   A grade is not the same thing as a model;
one model (such as Waltham's Model 1883) may exist in several different grades, while one grade-name may be
applied to many different models.   The manufacturer's own name is usually shown as well, either on the dial or in a
subordinate position on the movement.   The practice may have been partly a means of preserving the traditional
appearance of the back-plate, with a personal signature rather than that of a factory.

GRAHAM, George

(1674-1751) English clock- and watchmaker, inventor of the dead-beat escapement for clocks and early champion of
the cylinder escapement for watches;  he is said to have made no verge watches after 1727.   Also noted for his
generous support of the young John Harrison.

GRAHAM DIAL

Name sometimes used for the typical English watch dial of the period 1710-1765, with (reading from the edge inwards)
a large circle of arabic minute numerals at 5-minute intervals, a minute track, a roman chapter-ring and a single circular
line, all painted in black on a white enamel ground.   From the early 1760s the inner circle began to be omitted and the
5-minute figures grew steadily smaller until by 1790 they were often omitted altogether, while the chapter-ring
numerals grew ever taller and narrower.

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.

GUNMETAL

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.

HACK-WATCH

(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 with the medical profession in mind.   Later in the century the
hack-watch was superseded by the chronograph.

HAIRSPRING

A synonym for balance-spring, regarded by some English writers as ‘colloquial’ but certainly established in
mid-19th-century British usage.

HALF-CHRONOMETER

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.

HALF-HUNTER

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 this chapter-ring is engraved on the cover itself and often picked
out in blue enamel.

HALF-PLATE

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

(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 temperature changes) to balance-springs.   Watch manufacture
ceased in 1969, although the name survives today.

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 appointed by Parliament in 1714 for a method of
determining a ship's longitude, and in either 1728 or 1730 (authorities differ) he travelled to London, bearing a
statement of his theories and drawings for a friction-free escapement and a temperature-compensated pendulum;  this
made an impression on George Graham who set Harrison up with a generous loan.   By 1736 Harrison had completed a
table-top timekeeper which performed most encouragingly on an informal trial at sea;  two more large machines followed
in 1739 and 1757, but Harrison's own scruples prevented their being submitted for the trials laid down in the 1714 Act.
Finally, in 1761, a much smaller fourth chronometer, watch-like and truly portable, was sent on an official test voyage
to Jamaica and back, followed (after stubborn objections to the results by some members of the Board of Longitude) by
another to Barbados in 1764.   ‘No. 4’ amply met every requirement, but it was not until nine years later, and with the
personal intervention of King George III, that Harrison finally received the appointed reward.  He made another
chronometer in about 1769.   Harrison's ideas were idiosyncratic and were quickly superseded, but two of his inventions
- maintaining-power for watches and a bimetallic pendulum - passed into the main stream of horological practice, while
another, a caged roller-bearing, found many applications in other forms of engineering.

HEBDOMAS

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 regulator from the back;  these items were therefore
transferred to the front of the movement and made accessible through a hole in the dial.

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’);  he sems to have conceived the idea of applying
a spring to the balance many years before Huygens but not to have found a practical form for it.   He probably devised
the anchor escapement for clocks and was certainly the inventor of a gear-cutting device which simplified clock and
watch manufacture.

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.

HORN

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.

HOROLOGY

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, Breguet, Harrison, Tompion etc.)

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 independently until 1903 when the company was taken
over by the Keystone watch company, who continued the name without loss of prestige until 1930.

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 precedency.

IMPULSE

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 ordinary flat balance-spring as introduced in the 1670s was
only roughly isochronous (and has often grown even less so with time through metal-fatigue, especially in verge
watches).   Precision makers of the next century devised various special configurations to make this quality more
complete;  Breguet's overcoil was the most successful of these and the only one which survives today.

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.

JEWEL

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 by Pierre Debaufre and Nicolas Facio de Duillier in 1704
and was applied sparingly in the 18th century, chiefly by English makers who thereby overtook the French as the world's
leaders in watchmaking.   Jewels became much more common after 1820.   In reckoning up the number of jewels in a
movement it is usual to include the lever pallets and also the roller jewel;  this last item accounts for the fact that the
total is almost always an odd number, whereas in Swiss movements (with cylinder escapements) it is frequently even.

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.

KARUSSEL

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

KEY-WOUND/KEY-SET

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 placing the key over the squared end of the cannon pinion;
European makers, until after 1800, preferred a winding-hole in the dial, while after that time both winding and setting
was carried out through the cuvette at the back.   Key-winding persisted in Britain until after 1900.

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 so on up and down.   Measurements were taken across
the diameter of the front plate, not the case or even the dial.   The American gauge is a development of the Lancashire.

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-engineering, notably to J. G. Graves of Sheffield.
U.S. and Swiss imports overwhelmed the company in the 1900s.   Not to be confused with the Lancaster Watch
Company, a name used 1877-1892 by an American company which afterwards became Hamilton.

LEAF

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

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 with the fusee.

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 beyond it.   This plan is known as the Lépine calibre.   The
term is sometimes applied to any early (say pre-1840) alternative to the full-plate or three-quarter-plate layout.
Chinese market watches preserved something very like the original form throughout the nineteenth century.

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 much simpler and more practical means to
achieve its results, but whose promising results in tests at sea were never followed up.

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 with the teeth of the escape-wheel;  the other end of the
lever is forked and engages with the impulse-pin which is mounted on a steel disc (the roller) centred on the
balance-staff.   The lever was invented by Thomas Mudge in 1757 and applied by a few 18th-century makers including
Breguet;  its use gradually spread after about 1815.   It has two main forms:  the side lever with the pallet-arm integral
with and parallel to the lever (favoured by 19th-century British makers), and the straight-line lever in which the
pallet-arm is at a right angle to the lever, preferred in America from about 1870 and afterwards universal.

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 many early stem-wound watches;  pendant or stem
setting was distrusted because it was felt that the crown might spring out or be pulled out accidentally, allowing the
hands to get out of place.

LIFT

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 solely responsible for lift;  in the straight-line type the teeth are cut
off obliquely and share the special shaping with the pallets.

LIGNE

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.

LIVERPOOL

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 developed the rack-lever and popularised the detached lever and the use
of jewels and compensated balances.   Many Liverpool movement found their way to the United States —some exported
by the manufacturers, others carried in emigrants' pockets — and their influence is very noticeable in the earliest
products of the American industry.

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.

LOCKING

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

LONGITUDE

Position on the earth's surface eastward or westward of an agreed starting-point (meridian – 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 so many variables that it could scarcely be done by
observation alone.   The simplest method was to carry on board an accurate timekeeper which showed the time at the
chosen meridian, and compare it with the time at the ship's location as determined by observation of the sun;  the
difference between the two could be reliably translated into terms of distance, but the clock had to be of outstanding
precision and reliability, since an error of only four seconds could represent as much as a mile if the ship were near the
equator.   John Harrison's fourth chronometer (1759) was the first practical solution.

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.


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