Time & Clocks Dictionary
Falling Ball Clock: A form of GRAVITY CLOCK invented in the seventeenth century. The clock has a ball-shaped brass case with a 24 hr. MOVING BAND which turns round its 'equator'. The hour is indicated by an image, such as a cherub, fixed to the case. A cord wound round a BARREL in the ball comes out of the top of the case. The clock is suspended from this and slowly descends-like a spider on a thread-being driven by its own weight. When it hangs low, it is raised by hand and the cord 'disappears' inside the clock, being wound back on to the barrel by a spring.
False Bob: Another name for a MOCK PENDULUM.
Farmer's Watch: Large pocket watch with VERGE ESCAPEMENT and an enamelled dial showing a farming scene, made from about 1820 to as late as 1880.
Farouk Collection: Exceptional collection of watches, including some with pornographic AUTOMATA, sold after Farouk was deposed as King of Egypt.
Fellows Watch Collection: Antique watches bequeathed to the British Museum in the late nineteenth century by Sir Charles Fellows. Lady Fellows made water-coloured drawings of the watches as they were bought, before restoration, which are exceptionally beautiful and accurate and now belong to the Royal Institution, London.
Finding the Longitude: A ship has to know its position East or West by 'finding the longitude'. It is relatively easy to find the position North or South by Sun or stars; that to the East or West is complicated by rotation of the Earth and until the eighteenth century ships often sailed thousands of miles out off course and were lost. The Spanish, Dutch, Venetians, and British (in 1714) offered big prizes for methods of finding the way at sea. The British one of £20,000 was the only one paid, to John HARRISON for his marine timekeeper. The principle of using a timekeeper was this. It was set to the time at the port which the ship left, say Bristol. Suppose the ship sailed West; the Captain would compare his LOCAL TIME, obtained from observations of the Sun, with the clock's time. If there was an hour and a half's difference, he was 221° west of Bristol because the Earth turns 15° in an hour. The method is still used, but the ship's MARINE CHRONOMETER IS kept t0 GREENWICH MEAN TIME by RADIO TIME SIGNALS and compared with local time. See Navigation.
Finial: A decoration on top of a clock case, to 'finish it off'. Common types in brass were balls with points on top, flambeaux (flames), acorns and pineapples, urns, spires. They were used singly (and also called 'terminals') or in groups.
Fire Clock: In Tibet and China, joss-sticks were once used for timekeeping. The stick was a strip of cane coated with a dried mixture of clay, sweet burning sawdust, and gold dust. Lit at one end, it smouldered for several days. Marks along the stick showed the hours. A fire-stick was used as an alarm by tying two little weights by a thread to the appropriate place. When the stick smouldered to that point, the thread burnt and the weights dropped with a clang into a copper bowl. See Candle Clock.
Five Minute Repeater: A REPEATER CLOCK or WATCH that sounds the last hour on a lower note, the last quarter on a TING TANG, and one blow on the higher note for each 5 minutes past the quarter. Operated by a slide on the side of a watch and a pull cord on a clock.
Flamsteed, John: First ASTRONOMER ROYAL, appointed in 1676, and originator of the NAUTICAL ALMANAC, now prepared in five countries. See Greenwich Observatory.
Flat Bed: Type of construction of modern TURRET CLOCKS with the ARBORS (axles) in a row across a steel, or cast iron, horizontal frame. Popularized by Lord GRIMTHORPE in 'BIG BEN' in 1859, but used as early as 1763 in the church of Notre Dame, Versailles, France.
Flexible Watch Band: A metal wrist-watch BRACELET that is flexible, but not an EXPANDING BRACELET. Usually of gold. There are two main forms of construction, by weaving gold wire (called 'milanese') and by closely fitting jointed links. The second type is often known as 'brick' or 'pave'. Short rectangular tubes fitted end to end over woven wire give a similar effect. Some of these bracelets are triumphs of the jewellers' art and if given 'satinized' finish the joints are almost impossible to see. The band is normally soldered permanently to the watch case.
Floating Balance: An accurate escapement for clocks invented in Germany in 1950 but used in British clocks. The BALANCE WHEEL IS suspended from its CYLINDRICAL HAIRSPRING t0 reduce friction, arid it 1S FREE SPRUNG in some versions. Its advantage over the short PENDULUM clock is that it is portable and remains accurate even if the clock is tilted.
Floral Clock: Large public clock set out in bedding plants on the ground. Some strike; a few are CUCKOO CLOCKS.
Fly: A governor or rotating fan used to slow down a striking or chiming mechanism. Incorporates an elementary clutch; or ratchet freewheel on large clocks. That on a LONG CASE CLOCK is about 1 1/2 in. across and that on BIG BEN'S clock, about 6 ft. The earliest known is on a German or Italian clock of about 1550. Some of the latest have an arrangement to decrease the area of the fan as the speed falls (i.e. as the MAINSPRING runs down) so that the intervals between strokes remain constant.
Fly Back: The arrangement which returns a hand to zero on a TIMER or CHRONOGRAPH by means of a heart-shaped cam.
Flying Pendulum Clock: Novel (and inaccurate) clock invented by P. Closon in 1883. The ESCAPEMENT is a length of thread with a ball on the end, which swings in a circle, but is interrupted each 180° by twisting and untwisting round one of two vertical rods on top of the clock. Manufacture was resumed in 1959 in Germany for a U.S.A. company.
Fob Watch: Now the name for a watch hanging on a short decorative strap, or chain, and usually combined with a brooch worn on the lapel, the watch dial being upside down so that it can be read. Originally a pocket watch on a short chain, after fuppe, low German for 'pocket'. A nurse's watch is often of this type. Also a CHATELAINE WATCH. For men, the 'fob chain' is an alternative to the watch chain or ALBERT, and is in fact for a pocket watch.
Foliot: Swinging bar with adjustable weights on the end. Employed as the earliest mechanical time controller, with a VERGE ESCAPEMENT. The bar is twisted first one way and then the other and its RATE can be increased by moving the weights on the ends towards the centre. The word was first used by Jean Froissart, the French chronicler, in 1369, and means 'to dance about madly'. See Salisbury and Cassiobury Clocks.
Forgeries: English watches were often forged on the Continent during the eighteenth century and falsely signed 'TOMPION', 'QUARE', 'GRAHAM' et al., some names being misspelt. The MOVEMENTS inside were cheap and not even imitations. BREGUET'S work was also forged which made him devise his SECRET SIGNATURE. Clocks have been forged, but much more realistically. Not infrequently a case has become separated from its original MOVEMENT and both have been built into complete clocks, so that there are two 'genuine' antiques instead of one. Dials with famous names engraved on them have been given to inferior movements and existing movements given a new 'antique' case. There are instances, too, of an original engraved name being scraped off and new one, e.g. Thos. TOMPION, engraved in its place. The situation is further confused by the fact that in the nineteenth century many genuine makers, Barraud, Perrigal, Dwerrihouse, and others bought their 'bread-and-butter clocks' from embryo factories and had their own names engraved on dials and movements; thousands of retailers, middlemen, and even customers also had their names engraved to appear as makers. As the price goes by the name, identical clocks sell for different prices, but these are not truly fakes. On the Continent, old German STACKFREED watches have been faked in at least three places, and as recently as from after the Second World War to 1957 in Belgium. Many electrotype copies of old Augsburg clocks have been produced. There is also, apparently, an ASTROLABE 'factory' in Mexico. Among French fakes a quantity of MOVING ARM WATCHES were made in the nineteenth century in imitation of an earlier period and huge quantities of electrotype copies of earlier French clocks were made during the Second Empire from 1852 to 1870. Until about 1914 various faked WATER CLOCKS frequently bought as genuine today were listed in the catalogue of a Birmingham manufacturer. Some bear the date 1640.
Form Watch: Watch made in the shape of something else, such as a crucifix, SKULL, book, globe, animal, etc.
Four-Hundred Day Clock: A German clock under a glass dome with a TORSION PENDULUM, which runs for a year with one winding. Invented by Anton Harder about 1880. Still made in quantity.
Frame: The structure in which the wheels and other parts of a clock or watch are built. In TOWER CLOCKS it was once VERTICAL or BIRDCAGE and is now FLAT BED; in modern domestic clocks and early watches two brass PLATES are employed, and in later watches an EBAUCHE.
Free Pendulum Clock: Most accurate type of pendulum clock ever made. One at the Edinburgh Observatory has kept time to within 1/10th sec. a year. Invented by R. J. Rudd (1898) and made practical by W. H. Shortt (1921). The Shortt free pendulum is kept in a vacuum chamber and has no work to do. Another (slave) pendulum, linked to it, does all the work. The linking of the two is very ingenious. The slave is set to run about 6 sec. a day slow. Every half minute it releases a GRAVITY LEVER t0 IMPULSE the free pendulum. Because of the geometry of this and the PALLET on which it acts the free pendulum accepts the impulse in its own time. After impulse, the gravity arm falls on a contact, which causes an electro-magnet to reset it. This contact also: (1) releases a gravity arm to impulse the slave, (2) operates the master clock dial, and (3) brings an arm into line with a piece of clock spring on the slave pendulum. When the slave pendulum is slow, the arm bends the clock spring to accelerate the slave pendulum into step with the master. The resetting of the slave's gravity arm by contacts and electro-magnet also provides the signal for operating a slave dial. Now superseded in observatories by QUARTZ CLOCKS.
French Horological Industry: One of the world's oldest and may have been the first. The earliest known maker was Julien Couldray, who made two watches set in dagger handles in 1518. Early centres were Blois (see Enamelled Watch), Paris, and Lyon. When the Huguenots were persecuted, many watchmakers went to Geneva which greatly strengthened the Swiss HOROLOGICAL INDUSTRY. After the French Revolution, Laurent Megevard, backed by the government, set up an industry in Besancon. Other pioneers were JAPY and SULLY. The present industry is organized like the Swiss. There are 250 EBAUCHES manufacturers, 350 FINISHERS, and ten complete watch manufacturers centred in the Doubs, the Haute-Savoie and the Seine. The clock industry is spread throughout France and produces about 21 million alarms and other clocks yearly. Export watches have t0 satisfy QUALITY STANDARDS.
Frequency Comparison Meter: Special meter used at electricity power stations to compare mains frequency with a MASTER CLOCK, so that SYNCHRONOUS CLOCKS are kept t0 MEAN TIME.
Friction Spring: Spring acting as a clutch for hand setting; also one for taking up backlash of a CENTRE SECONDS HAND.
Frictional Rest: Most ESCAPEMENTS release a tooth of the ESCAPE WHEEL for a fraction of a second and then hold it up. With some, like the CYLINDER ESCAPEMENT, the escape wheel tooth is held up by its resting against part of the moving BALANCE WHEEL. Such frictional rest interferes with the free swing of the balance wheel. The LEVER ESCAPEMENT locks an escape wheel tooth without touching the balance wheel, and is therefore free.
Fromanteel: Famous family of clockmakers in London, which originated from Holland. They were named Ahasuerus, John and Abraham. John learned how to make HUYGENS pendulum clocks in Holland and the Fromanteels were the first to introduce them into England in 1658. Evelyn refers to 'our famous Fromantil' in his Diary. They worked at Mosses Alley, Southwark, and at 'The Mermaid' in Lothbury.
Front Wind: Clock wound through the dial.
Frosting: The grey matt finish given to steel parts of watches by rubbing with oilstone dust in olive oil. Frosting is carried out before GILDING if a final matt surface is required.
Fusee: A MAINSPRING gives less and less power as it runs down, which affects timekeeping. The power can be equalized by a fusee-a grooved and trumpet-shaped pulley-which the mainspring BARREL drives by a chain or length of gut. (Fusee means 'thread'.) Fusee leverage increases as the mainspring runs down. Shown as early as about 1485 in Leonardo da Vinci's sketch books and still used today in the MARINE CHRONOMETER, and special clocks.