01
Escapement types
- Verge escapement c. 1300 – 1800
- The earliest mechanical escapement, in use from the 13th through early 19th century. A crown wheel (a wheel with teeth perpendicular to its axis) interacts with two pallets on a vertical staff — the verge — alternately catching and releasing the teeth to produce the characteristic recoil. The verge escapement required a foliot or balance wheel for regulation and is identifiable in clocks by the distinctive crown wheel and in watches by its very thick, round movement and the lack of a hairspring before 1675.
- Anchor / Recoil escapement c. 1670 – present
- Introduced in England around 1670, the anchor escapement uses a pendulum and an anchor-shaped pallet that alternately engages the teeth of an escape wheel. On each swing, the pallet slightly pushes back (recoils) the escape wheel — hence "recoil." More accurate than the verge by an order of magnitude, enabling the development of longcase clocks with seconds-beating pendulums. The anchor-shaped pallet frame is immediately identifiable.
- Deadbeat escapement c. 1715 – present
- A refinement of the anchor escapement devised by George Graham around 1715, eliminating the recoil of the pallet faces. The escape wheel teeth rest momentarily on flat pallet surfaces (the "dead" zone) before being released, producing no recoil. Significantly more accurate than the recoil anchor; the standard escapement in high-quality regulators, astronomical clocks, and precision bracket clocks from the early 18th century onward.
- Cylinder escapement c. 1695 – 1900
- A compact escapement developed by Thomas Tompion and George Graham for thin pocket watches, in which a hollow cylinder on the balance staff acts as both impulse receiver and detent. Smooth-running and quiet but delicate and difficult to service; the thin cylinder walls are prone to wear. Common in 18th–19th-century Swiss and French pocket watches; the thin, flat watch profile it enabled was fashionable throughout the period.
- Lever escapement c. 1759 – present
- The dominant watch escapement from approximately 1820 onward, invented by Thomas Mudge around 1759. A pivoted lever with two pallets engages an escape wheel; a draw mechanism locks the lever securely between impulses, making it shock-resistant. More robust than the cylinder and more accurate than the verge; became the standard for quality pocket watches and remains the standard for mechanical watches today.
- Platform escapement Swiss-made self-contained unit
- A self-contained escapement unit — typically a lever or cylinder type — mounted on a removable brass platform and used in carriage clocks and some bracket clocks. The platform can be lifted out for servicing without disturbing the clock's main movement. Most platform escapements are Swiss-made; the maker's name or trademark is often stamped on the platform base plate. Condition of the platform is the primary quality indicator for antique carriage clocks.
02
Movement parts
- Balance wheel oscillator
- The weighted wheel that controls the timekeeping in a watch or portable clock — the equivalent of a pendulum. Its rate of oscillation is determined by the tension of the hairspring. Balance diameter, material (brass, bimetallic for temperature compensation, glucydur alloy), and the regulation method (index, Massey, micrometric) are key period and quality indicators. A bimetallic compensation balance indicates a movement of the late 19th or early 20th century.
- Hairspring / Balance spring spiral spring
- The fine spiral or helical spring attached to the balance wheel collet that provides the restoring force for its oscillation. Invented independently by Huygens and Hooke around 1675. The shape of the terminal curve — flat, Breguet overcoil, or Phillips — is a significant period and quality indicator. Damage to the hairspring is the most common cause of rate errors in antique watches.
- Mainspring power source
- The coiled steel spring stored in the going barrel that provides the driving force for the movement. As it unwinds, it drives the gear train. Fusée movements separate the mainspring barrel from the train by an intermediary cone, equalising the torque; in barrel movements (keyless Swiss watches from the 1850s) the spring drives the train directly. A worn or broken mainspring is the most common cause of stopping.
- Fusée equalising cone
- A conical spool connected to the mainspring barrel by a chain or gut cord that equalises the torque delivered by the mainspring as it runs down. The fusée compensates for the mainspring's decreasing force by changing the leverage ratio — as the spring weakens, it acts on a larger diameter. The presence of a fusée is the primary indicator of a quality English or Continental movement; mass-produced Swiss movements from the 1850s onward dispensed with it.
- Cock balance bridge
- The bridge that supports the upper pivot of the balance wheel staff, typically decorated with pierced and engraved scrollwork. The cock's shape — the form and engraving of the table, the shape of the foot, and the curvature of the neck — is the most useful single dating indicator for English pocket watches. Pre-1700 cocks have a table covering only the balance; post-1700 cocks extend to the full width of the plate. Continental cocks are less pierced and more architecturally styled.
- Jewels bearing stones
- Hard stones (originally natural rubies and sapphires, now synthetic corundum) set in the movement as bearing surfaces to reduce friction at pivot holes and impulse surfaces. The jewel count — 7, 15, 17, 21, 23 — indicates the movement's quality and complication level. Antique movements used genuine rubies, identifiable by their rich red colour and characteristic setting style in polished gold or brass chatons (settings).
03
Clock types
- Longcase clock grandfather / grandmother clock · c. 1660 – present
- A floor-standing weight-driven clock with the pendulum and weights housed in a tall wooden case. The seconds pendulum (39 inches, beating once per second) became standard from 1670 and required the tall case. English longcase traditions developed distinct regional styles — London (ebonised or walnut marquetry), Lancashire (oak with inlaid decoration), Scottish (mahogany, architectural hood). Major makers: Tompion, Graham, Knibb (London), Frodsham (Liverpool).
- Bracket clock spring-driven mantel clock · c. 1660 – 1900
- A spring-driven clock designed to rest on a bracket, shelf, or mantelpiece rather than the floor. Typically contains a fusée movement and strikes the hours on a bell. Named for the wall bracket originally provided with it. The 1660–1720 English bracket clock in ebonised case with gilt brass mounts — by makers such as Tompion, Quare, and Fromanteel — represents the peak of English horology.
- Carriage clock pendule de voyage · c. 1800 – 1900
- A portable spring-driven clock with a platform escapement, typically in a rectangular gilt-brass case with bevelled glass panels and a folding handle. Developed by Breguet for Napoleon's campaigns and subsequently mass-produced in France. Most carriage clocks encountered today are French, from the Saint-Nicolas-d'Aliermont region. Quality ranges from simple timepieces to elaborate répétition and minute-repeating examples with striking, chiming, and alarm functions.
- Vienna regulator Viennese precision wall clock · c. 1780 – 1870
- A precision weight-driven wall clock developed in Vienna, characterised by a seconds-beating deadbeat escapement, a slender weight-driven movement, and a glazed mahogany or fruitwood case with architectural pediment. High-quality Viennese regulators achieve remarkable precision; later German productions copied the form but rarely the quality. The one-weight (single train, timepiece only) and two-weight (going and striking) variants are the most common.
- Skeleton clock display clock · c. 1830 – 1880
- A clock in which the plates are cut away to expose the wheelwork — purely a display piece. Popular in England and France during the 19th century; the English Gothic cathedral skeleton clock, imitating a cathedral façade, is particularly characteristic. Skeleton clocks are exceptionally vulnerable to dust and damage; original glass shades are essential to value and the practical preservation of the movement.
04
Watch types
- Pocket watch personal timepiece · 16th century – 1930s
- A portable timepiece carried in a pocket, typically suspended from a chain. The standard personal timepiece from the 17th century through the early 20th century. Key identification features: case material (gold, silver, base metal), case form (open-face, hunter, half-hunter), movement calibre and quality (jewel count, finish), and winding/setting mechanism (key-wind, stem-wind).
- Hunter case full hunter · hinged cover
- A pocket watch case with a solid hinged lid covering the dial, opened by pressing the crown or a separate push-piece. Protects the crystal and dial from dust and damage. Common in 19th-century dress watches; gold hunters by makers such as Patek Philippe and Audemars Piguet command significant premiums.
- Half-hunter case demi-hunter
- A variant of the hunter case with a central round aperture or glass panel in the hinged cover, allowing the approximate time to be read without opening the case. Roman numerals painted or engraved on the inside of the lid correspond to the dial positions. Popularised by Napoleon, who wore a white-enamel half-hunter.
- Repeating watch striking watch on demand
- A watch that sounds the time on demand when a slide or push-button is activated. Types: quarter-repeater (hours and quarters), half-quarter repeater, five-minute repeater, and minute repeater (hours, quarters, and individual minutes). The minute repeater mechanism is among the most complex in horology. Swiss and English minute repeaters of the late 19th century are among the most collectible antique watches.
- Chronograph seconds recorder
- A watch with a secondary seconds-recording function that can be started, stopped, and reset independently of the main timekeeping. Developed from the 1820s; early chronographs used a stylus to mark a paper dial. Push-button control (monopoussoir) and split-seconds (rattrapante — two superimposed seconds hands for recording lap times) chronographs represent the highest level of complication.
05
Notable makers
- Thomas Tompion 1639–1713 · London
- Called the "Father of English Clockmaking," Tompion was appointed Clockmaker to Charles II in 1676 and worked closely with Robert Hooke. His bracket clocks, longcase clocks, and watches established the template for English horology. Approximately 5,500 watches and 650 clocks are attributed to Tompion; each is serially numbered in his workshop records, allowing verification. A signed Tompion is among the most sought-after pieces in antique horology.
- George Graham 1673–1751 · London
- Tompion's apprentice and eventual successor. Graham invented the deadbeat escapement (c.1715), the mercury compensation pendulum, and the cylinder escapement. His precision regulators were used as standards for Greenwich Observatory. Graham continued Tompion's numbering system and maintained his workshop's standards. A Graham-signed movement is a reliable indicator of the finest English craftsmanship.
- Abraham-Louis Breguet 1747–1823 · Paris / London
- The most innovative watchmaker in history. Breguet invented the tourbillon (patented 1801), the overcoil (Breguet) hairspring, the self-winding watch, the pare-chute shock absorber, and the Breguet numeral. His watches are among the most researched antique timepieces — the Breguet archive in Paris can verify signed examples. Forgeries are numerous; authentication requires archive consultation and technical examination.
- John Harrison 1693–1776 · Yorkshire / London
- A self-taught English joiner and clockmaker who solved the longitude problem with his four marine chronometers (H1 through H4). H4, completed in 1759, achieved a daily rate error of one-third of a second — far exceeding the Longitude Prize requirements. Harrison's work directly enabled accurate oceanic navigation and the British Empire's naval expansion. H1 through H4 are preserved at the National Maritime Museum, Greenwich.
- Thomas Mudge 1715–1794 · London
- A pupil of George Graham and one of the most significant innovators in watch history. Mudge invented the lever escapement around 1759, though its potential for mass production was not recognised in his lifetime. His marine chronometers challenged Harrison's claims. Two of Mudge's original lever-escapement watches survive; the lever escapement he invented became the universal watch standard in the 19th century.
06
General terms
- Horology the science of time measurement
- The science and art of measuring time, encompassing the design, construction, and study of clocks and watches. From the Greek hora (hour) and logos (word, study). A horologist designs, makes, or repairs timepieces; a horological historian studies their artistic, technical, and social history.
- Calibre movement specification
- The specific movement design of a watch, identifying its dimensions, configuration, and technical characteristics. Swiss movements from established manufacturers have documented calibre numbers recorded in reference works (Flume, Bestfit). Knowing a movement's calibre allows identification of its parts suppliers, date range, and relative quality within a manufacturer's range.
- Ébauche unfinished movement blank
- A partially finished movement — the plate, bridges, and basic train — supplied by a specialist manufacturer to other firms for completion and casing. Swiss ébauche manufacturers in the Vallée de Joux supplied movements to hundreds of finishing firms. An ébauche movement bears the calibre number of the producing factory. The ébauche system enabled the Swiss watch industry's extraordinary productivity.
- Complications additional functions
- Features of a watch or clock beyond basic timekeeping — striking, alarm, repeating, calendar, chronograph, equation of time, and others. A watch with three or more significant complications is a Grand Complication. Complications significantly increase both the maker's skill required and the collector's interest, and accordingly command substantial premiums at auction.
- Regulator precision timepiece
- A clock designed and built specifically for precision timekeeping, used as a standard against which other timepieces are set. Regulators typically have a deadbeat escapement, a temperature-compensated pendulum, and a movement designed to minimise friction and interference. The dial is typically divided into separate subdials for hours, minutes, and seconds — never combined on a single hand.
- Signature maker's name
- The engraved name of the maker or retailer on the movement plate, dial, or cock. A movement signature is more reliable for attribution than a dial signature — dials were often signed by the retailer who sold the watch rather than the maker who made it. Where both exist and agree, attribution is confident; discrepancies require investigation.