Chapter XXV: Appendix: E (2)

ENGAGING FRICTION—Friction which results when the teeth of two wheels gearing together come into action before reaching the line of centers—that is, a line drawn from center to center of the gearing wheels.

ENGINE-TURNING—A pattern of curved lines cut into metal for decoration. Introduced about 1770 by Francis Guerint of Geneva. The earliest specimens were cut very deep but shallower cutting soon became the rule.

ENGRAVING—A form of ornamenting metals in which the design is cut into the metal. In "Champ-leve" engraving the ground is cut away leaving the design in relief.

EPACT—The excess in time of the solar year over the period of 12 lunar months, amounting to about 11 days. The new moons will thus fall about 11 days earlier in each succeeding year. In a calendar so arranged 30 days are taken off every fourth year, as an intercalary month, the moon having revolved once in that time, and the three days remaining would be the epact. The epact thus continues to vary until at the end of nineteen years the new moons return as at first.

EPICYCLOID—A curve generated by any point in the circumference of a circle as it rolls on the outside of the circumference of a fixed circle. This curve is the best for the face of the teeth of a driving wheel.

EQUATION CLOCKS—An obsolete form of clock which showed true solar or sun-dial time instead of mean solar, or average time.

EQUATION OF TIME—The difference between true time and mean, or averaged time. There are four days in the Gregorian year when the true time and mean time agree, and the equation of time is zero: These are December 24, April 15, June 15, and August 31. Between the first two dates and the last two dates, true time is earlier than mean time; for the other two periods of the year it is later.

ESCAPE COCK—The bracket which supports the upper ends of the escape wheel and pallet staff arbors.

ESCAPEMENT—The device in a watch or clock which regulates the motion of the train thus distributing the power of the main-spring. It communicates the motive power to the balance or pendulum. Escapements are of three classes: recoil, dead, or dead-beat; and detached.

ESCAPEMENT, ANCHOR—The recoil escapement, invented by Hooke, used in most house clocks. A name also applied to one kind of Lever Escapement with an unusually wide impulse pin. The recoil escapement is one in which each tooth of the escape wheel, after it comes to rest, is moved backward by the pallets. Altho one of the easiest escapements to set out correctly the pallets are often improperly formed making an escapement which gives indifferent service. As a timekeeper the anchor escapement is inferior to the dead-beat escapement.

ESCAPEMENT, CHRONOMETER—A detached escapement in which the escape wheel is locked on a stone carried in a detent, and in which the teeth of the escape wheel impart an impulse to a pallet on the balance staff with every alternate vibration. Used in Marine Chronometers.

ESCAPEMENT, CROWN-WHEEL—Of the recoil type, and the earliest known escapement; to be found in Henry de Wyck's clock. Not suitable for watches. Practically the same principle as Verge or Vertical Escapement used in watches for so many years.

ESCAPEMENT, CYLINDER OR HORIZONTAL—Invented by Thomas Tompion in 1695—later improved and brought into general use by Graham. It dispensed with the then common vertical crown-wheel—hence the term "horizontal" and permitted thinner watches. This escapement is frictional, the balance being carried on a hollow cylinder whose bore is large enough to admit the teeth of the escape wheel. The cylinder is cut away where the teeth enter and the impulse is given by the wedge shaped teeth striking against the edge of the cylinder as they enter and leave. Used at this time in the cheaper Swiss watches.

ESCAPEMENT, DEAD-BEAT—Any escapement in which the pallet face is so formed that the escape wheel remains dead or motionless during the supplementary arc of the balance or swing of the pendulum. As invented by George Graham, the wheel is much the same as the wheel in the anchor escapement, the difference lying in the shape of the pallets. Each pallet has a driving face and a sliding face. It is so arranged that the impulse is given the pendulum at the midpoint of its swing thus allowing the swing to adapt itself to the impulse and keep the time constant. The pallets are faced with jewels so that there is slight friction. Used in high grade clocks such as regulators and astronomical clocks.

ESCAPEMENT, DETACHED—Any escapement in which the balance or pendulum is for some time during each vibration free from the pressure of the train. Detached escapements are used in chronometers, most watches and in turret clocks. They are of value in any movement where the motive power varies greatly—hence in turret clocks. Examples: Chronometer, lever, and gravity escapements.

ESCAPEMENT, DOUBLE THREE-LEGGED GRAVITY—Invented in 1854 by E. B. Denison, Esq., for the great clock at the Houses of Parliament. It is the best escapement for very large clocks where the hands are exposed to the action of the wind and snow, because it admits of great driving power in the movement without its sensibly affecting the escapement as would be the case in the dead-beat type. The impulse to the pendulum is given by the weight of the lever arms falling through a given distance and is therefore constant. This escapement consists of two gravity impulse pallets pivoted in a line with the bending point of the pendulum. There is a locking wheel made of two thin plates of three teeth each. Between these plates are the three pins that lift the pallets. The locking is effected by blocks screwed to the front of one pallet and the back of the other. Impulse is given by the pallets in turn striking the pendulum rod. The pendulum rod serves to unlock the wheel. The arrangement is such that the lifting pins have a little free run each time. Since the pallets are always lifted the same distance they give a constant impulse to the pendulum.

ESCAPEMENT, DUPLEX—Invented by Hook; later improved by Tyrer. Very accurate but as originally made was affected by any sudden motion, and hence of little use in watches. The escape wheel has two sets of teeth. Those farthest from the center lock the wheel by pressing on a hollow ruby cylinder fitted round the balance staff and notched so as to permit the passing of the teeth as the balance moves in a direction opposite to the wheel's motion. The second set stand up from the face of the wheel and one gives impulse to the pallet every time a tooth leaves the notch. This is not a detached escapement, but there is little friction. As improved this escapement was used in the famous Waterbury watches.

ESCAPEMENT, FOLIOT—A form of escapement actuated by a foliot balance. See _Foliot_.

ESCAPEMENT, FOUR-LEGGED GRAVITY—Invented by E. B. Denison (Sir Edmund Beckett). The same in principle as the Double Three-Legged escapement, only it has but one escape wheel with four teeth or legs instead of two wheels with three legs each. The wheel has two sets of lifting pins—one acting on each pallet. Occasionally used in regulators and other clocks with a seconds pendulum, but of doubtful, if any, advantage over the Graham dead-beat escapement.

ESCAPEMENT, FRICTIONAL—Any escapement in which the balance is never free from the escapement. Examples: The Cylinder, Duplex and Verge types.

ESCAPEMENT, GRAVITY—An escapement which gives impulse to the pendulum by means of a weight falling through a constant distance. Of use in turret and other exposed clocks where the hands' movements are affected by wind, rain, and snow. See subtitles under these headings: _Double Three-legged Gravity_; _Single Three-legged Gravity_; _Four-legged Gravity_; _Six-legged Gravity_.

ESCAPEMENT LEVER—Invented by Thomas Mudge about 1765. It is the preferred escapement for watches because of the certainty of its performance. Possibly inferior to the chronometer escapement as a timekeeper. Its most noticeable defect is the necessity of applying oil to the pallets, the thickening of which affects the action. There are many other kinds of lever escapements. The Mudge escapement was essentially like the modern Double Roller. The connection between the balance and the escape wheel is made by a lever to which the pallets are fastened, and into the forked end of which plays the ruby pin which is carried on a roller on the same staff as the balance. Each pallet has an impulse face and a locking face. The impulse is given by the escape wheel tooth striking the impulse face of a pallet and is communicated to the balance by the lever, raised by the pallet's movement striking the ruby pin in the roller. This ruby pin also serves to unlock the pallets by causing the lever to lift them in turn. This escapement is of the detached type. The action of the lever is kept within the desired limits by banking pins.

ESCAPEMENT, LEVER—CLUB TOOTH—An escapement like the Table Roller in the action of the lever and roller, but differs in the pallet action. The impulse planes are partly on the teeth and partly on the pallet. This is the standard watch escapement of today.

ESCAPEMENT, CRANK LEVER—An escapement with a small roller having a tooth like a pinion leaf projecting from its circumference. This tooth acts in a square notch cut in the end of the lever. The lever is formed like a fork the two points of which act as safety pins against the edge of the roller to prevent the lever from getting out of action with the roller. It necessitated very careful construction and was not so good as the Double Roller or Table Roller.

ESCAPEMENT, LEVER—DOUBLE ROLLER—This escapement has two rollers on the balance staff, the large one carrying the balance staff and the small one used for a safety roller only. The best form of lever escapement but more delicate, expensive, and difficult to make than the Table Roller; hence not so much used as the latter.

ESCAPEMENT, PATENT DETACHED LEVER—Introduced in 1766 by Thomas Mudge, but neglected for years thereafter even by Mudge himself. It was in some of its parts the model of the best form of lever escapement—the Double Roller. The first pallets had no "draw" on the locking faces which rendered the escapement peculiarly sensitive to jolt and jar. This may have suggested to Mudge the addition of the small roller, whose worth has been since unquestionably demonstrated.

ESCAPEMENT, LEVER—PIN-PALLET—A lever escapement with round pins for pallets, and the inclines on the escape teeth. Used in alarm clocks.

ESCAPEMENT, RACK-LEVER—Invented by Abbe Hautefeuille in 1734. Afterward made and improved by Berthoud and by Peter Litherland, who obtained a patent for it in 1794. It consisted of anchor shaped pallets on whose axis was fixed a rack, or segment of a toothed wheel which geared into a pinion on the axis of the balance. The balance was thus never free from the train and good timekeeping was made impossible. It is not now in use.

ESCAPEMENT, LEVER-RESILIENT—Invented by F. J. Cole about 1870. A form of lever escapement designed to obviate the evils of overbanking. The points of the escape-wheel teeth are bent toward the locking faces of the pallets, the bend in the tooth acts as the banking and no pins are required. It was abandoned because expensive to make and the danger of overbanking is not considerable.

ESCAPEMENT, LEVER—TABLE ROLLER—Excellent and very simple and the most common form today. It differs from the crank lever only in the action of the roller. The impulse pin instead of projecting beyond the edge of the roller is set within its circumference and raised above its plane.

ESCAPEMENT, LEVER—TWO PIN—A form of Lever Escapement in which the unlocking and impulse actions were formerly divided between two small gold pins in the roller and one in the lever. Later the two roller pins were discarded, and one broad jewel pin substituted.

ESCAPEMENT—PIN WHEEL—Invented by Lepaute about 1750. Similar in action to the dead-beat. A good and simple escapement for large clocks. The impulse is given the pendulum through the pallets by pins which stand out from the face of the escape wheel. Lepaute made these pins semi-circular and had his pallets of equal length acting on opposite sides of the wheel. Sir E. Beckett cut away part of the front of the pins which allows the pallets to act as in the diagram. The resting faces are arcs of a circle. It has been superseded by the gravity escapement for large clocks and is inferior to the dead-beat for small.

ESCAPEMENT, RECOIL—Any escapement in which the pallets actually force the escape wheel to turn backwards a trifle with each beat of the balance. Cheap and easy to make but inferior as timekeepers to the detached or dead-beat types.

ESCAPEMENT, RIGHT-ANGLED—A lever escapement so set that lines drawn between the centers of the balance, pallets, and escape wheel would form a right angle. See _Escapement, straight-line_.

ESCAPEMENT, SINGLE-BEAT—An escapement such as the Duplex, or Chronometer, whose escape wheel moves only at alternate beats of the balance or pendulum.

ESCAPEMENT, SINGLE THREE-LEGGED GRAVITY—Consists of two pallets and one three-legged locking wheel. Instead of the three pins for lifting as in the Double Three-Legged Gravity escapement there is a triangular steel block which acts against large friction rollers, pivoted one on each pallet.

ESCAPEMENT, SIX-LEGGED GRAVITY—A modification of the three-legged gravity escapement. The locking wheel has six teeth. One of the pallet arms is neutral and gives no impulse, hence impulse is given only at each alternate vibration. A much lighter driving weight than for the Double Three-legged Gravity escapement will suffice for this, since the rotations of the escape wheel required are only half as many.

ESCAPEMENT, STRAIGHT-LINE—An escapement of the lever type in which the escape wheel, pallets and balance are all in a straight line; an arrangement favored by the Swiss.

ESCAPEMENT, VERGE—Also called "Crown-wheel," or Vertical escapement. The earliest form of escapement on record. The inventor is not known, but the escapement was used on de Vick's clock. (1364.) It was used almost exclusively up to 1750 in spite of its manifest inaccuracy. The verge is a frictional recoil escapement. It consists of a crown-wheel, with eleven, thirteen, or fifteen teeth, shaped like those of a rip saw, and with its axis set at right angles to the pallets axis, or verge, which carries the balance. The verge is a slender cylinder as small as compatible with the required strength, from which project the pallets, two flat steel "flags"—at an angle to each other varying from 90° to 115°. The wheel runs in a watch in a plane at right angles to the face. Any variation in the motive power causes a variation in the arc of the balance swing. Therefore, since the time of oscillation depends on the arc of the swing, the time-keeping qualities were directly affected. This gave rise to the invention of the stack-freed and fusee, both contrivances to equalize the power of the mainspring. In spite of the many defects the verge escapement was one of the great inventions because the first escapement, and was used for centuries before superior kinds were devised. It necessitated thick and bulky watches.

ESCAPEMENT, VIRGULE—An early form of escapement invented about 1660 by Abbe Hautefeuille. Its action can be readily understood from the diagram.

ESCAPE PINION—The pinion on the escape-wheel arbor.

ESCAPE WHEEL—The last wheel of a train: it gives impulse to the balance, indirectly. Also called scape wheel. Easily identified by teeth resembling those of a circular saw.

FACE—1. Of a watch or clock is the dial. 2. Of the tooth of a wheel, that portion beyond the pitch line.

FACIO, NICOLAS—A Geneva watchmaker who invented the art of piercing jewels for use in watches, and in May, 1705, obtained a patent therefor in London. In December of the same year when he petitioned for a more extended patent he was opposed by the Clockmakers' Company, who produced in evidence proof that Facio was not first in this use of jewels, in an old watch of Ignatius Huggeford's with an amethyst mounted on the cock of the balance wheel. Facio's petition was denied. It was later discovered that Huggeford's jewel had nothing to do with the mechanism of the watch.

FAVRE, PERRET E.—In 1876 the chief commissioner in the Swiss Department and a member at that time of the International Jury on Watches at the Centennial Exhibition at Philadelphia. On his return home he was very emphatic in his endorsement of the American method of manufacture as compared to the Swiss.

FITCH E. C.—Made president of the Waltham Watch Co., in 1886. His long experience in watch case and movement making and his commercial training made his judgment on matters relating to watchmaking of value. He was the inventor of the screw bezel case.

FLANK—The flank of a wheel or pinion is the part lying between the pitch circle and the center.

FLIRT—Any device for causing the sudden movement of a mechanism.

FLY—A speed regulating device or governor consisting of a fan or two vanes upon a rotating shaft. Used in the striking part of clocks. By some believed to have been used on the earliest clocks—before the verge escapement—to check a too rapid descent of the weight.

FLY PINION—The pinion in a clock that carries the fly: a part of the striking mechanism.

FOB—Properly a watch pocket in the waistband of trousers. Commonly applied to the end of a chain or ribbon which is attached to the watch and hangs free from the pocket. One of the early examples was attached to a watch made for Oliver Cromwell in 1625 by John Midwall in Fleet Street.

FOLIOT—A straight armed balance with weights used as one of the earliest clock regulators. De Vick's clock is one example of it.

FOLIOT BALANCE—See _Foliot_.

FOLLOWER—Of two wheels geared together, the one to which the driver imparts motion is called the follower.

FORK—The fork shaped end of the lever into which plays the roller jewel.

FOURTH WHEEL—The wheel in a watch that drives the escape pinion and to whose arbor the seconds hand is attached.

FRAME—The plates or plate and bars of a watch or clock which support the pivots of the train.

FREE SPRING—A balance spring not controlled by curb pins. Used in chronometers and other fine time pieces where the spring is an overcoil.

FROMANTEEL, AHASUERUS—A clockmaker of Dutch extraction—maker of steeple clocks in East Smithfield. The family of Fromanteels were celebrated as having been the first to introduce the pendulum clocks into England. Their claim has since been contested in favor of Harris and Hooke.

FULL PLATE—A model in which the top plate is circular in form—the balance being above this plate. Used now in 18 size watches for railroad and other hard usage. They are made only in limited quantities.

FUSEE—Invented by Jacob Zech of Prague about 1525. Consists of a specially grooved cone-shaped pulley interposed between the mainspring barrel and the great or driving wheel of a watch or clock. The connection between the barrel and fusee was first made by a cord or catgut, later by a chain. In winding the spring the cord is drawn from the barrel on to the fusee—the first coil on the larger end. Thus the mainspring when fully wound uncoils the cord first from the smaller end of the fusee; and as it runs down gets the benefit of increased leverage by reason of the greater diameter of the lower part of the fusee. An excellent adjustment of the pressure on the center pinion can be made in this way. The fusee has been abandoned in watches to allow of thinness, but is still used in chronometers and clocks.

FUSEE CAP—A thin steel plate with a projecting nose on the smaller end of the fusee: a part of the mechanism to stop the fusee when the last coil of the chain is wound thereon.

FUSEE CHAIN—A very delicate steel chain connecting the barrel with the fusee of a watch, chronometer or clock. It replaced the catgut originally used and was first introduced by Gruet of Geneva about 1664.

FUSEE SINK—The sink cut in the top plate of a watch to give space for the fusee.

GALILEO, GALILEI—Commonly called "Galileo." A famous Italian scientist born in 1564 who discovered, among many other things, the isochronism of the pendulum vibrating through long or short arcs. The story goes that he noticed that a swinging chandelier in a certain cathedral took the same length of time to each vibration whether in long or short arcs—timing them by his pulse. He seems never to have applied this principle to clocks, although he issued an essay on the subject in 1639.

GALILEO, VINCENTIS—Son of the great astronomer, born about 1600. He aided his father in experiments and gave special attention to the application of the pendulum to clocks. He is claimed by some to have been the first to so apply the pendulum, in 1649, but this is disputed in favor of Richard Harris of London.

GENEVA—A city in Switzerland in which watchmaking was first established in that country. It is the center of the "hand" industry, and the city is honeycombed with garret-workers—so-called—making parts.

GERBERT (POPE SYLVESTER II)—Born in Belliac, Auvergne, in 920. In 990 Gerbert made some sort of a clock which attained wide fame. Some authorities claim that it was a clock moved by weights and wheels and some even claim for it a verge escapement. On the other hand, other authorities state positively that that story is a myth and that Gerbert's horologe was a sun-dial. It seems pretty well accepted that there was no escapement used, however, until more than two centuries after Gerbert's time.

GERMAN SILVER—An alloy of copper, nickel, and zinc—copper predominating. Really a white brass.

GIMBAL—A contrivance resembling a universal joint permitting a suspended object to tip freely in all directions. Marine chronometers are supported in their cases or boxes by gimbals. It was first applied to chronometers by Huyghens.

GNOMON—A simple and probably the most ancient instrument for marking time consisting simply of a staff or pillow fixed perpendicularly in a sunny place—time being reckoned by the changing length of the shadow or by its angular movement. In more recent times the title "gnomon" was applied to the style of the sun-dial.

GNOMONICS—The art of constructing and setting sun-dials taught especially in the seventeenth century.

GODDARD, LUTHER—Born at Shrewsbury, Mass., February 28, 1762—Died 1842. He was the first American to manufacture watches. He began in 1809 but unable to compete as to price with cheap foreign watches, retired after making about five hundred.

GOING-BARREL—The Swiss early abandoned the fusee in watches and cut teeth around the outside of the main-spring barrel so as to drive the train direct. Such an arrangement is called a going-barrel. It made possible a thinner and much simpler watch. American makers quickly adopted this device, but the English long clung to the fusee. It is sometimes claimed that the French were the first to adopt the going-barrel.

GOING FUSEE—A fusee with maintaining power attachment, so that the watch does not stop while being wound. Invented by Harrison.

GOLDEN NUMBER—Meton, an Athenian astronomer, discovered about 432 B. C. that every nineteen years the new and full moons returned on the same days of the month. This period is the cycle of the moon, called the Golden Number because the Greeks, to honor it, had it written in letters of gold. Anno Domini, the year of our Lord, fell on the second year of a lunar cycle. Hence, to find the Golden Number for any year, add 1 to the date (A. D.) and divide by 19. The remainder is the Golden Number for the year.

GOLD-FILLED—A sheet of brass sandwiched between two thin plates of gold and all brazed together. Gold-filled watch cases were introduced in America. They give very good wear.

GRAHAM, GEORGE, F. R. S.—An English watchmaker and astronomer, born in Cumberland in 1675. Died 1751. He was an apprentice of Tompion and succeeded to Tompion's reputation as the best watchmaker of his time. He invented the mercurial compensation pendulum, the dead-beat escapement, and perfected the cylinder escapement of Tompion and left it in practically its present form. He made ornamentation distinctly subsidiary to use. He was master of the Clockmakers' Company in 1722-23. He was buried with Tompion in Westminster Abbey.

GREAT TOM—The great bell which struck the hours on the first clock at Westminster. It was afterwards transferred to St. Paul's.

GREAT WHEEL—In a fusee watch the toothed wheel which transmits the power from the fusee to the center pinion. In a going-barrel watch it is represented by the toothed portion of the barrel drum.

GREENWICH OBSERVATORY—(England) Royal observatory founded 1675 to promote astronomy and navigation. There is at this observatory a standard motor clock which is the center of a system of electrically controlled clocks scattered over the Kingdom, and which thus keeps official time as our Naval Observatory clock does for the United States.

GRIMTHORPE—See _Denison, E. B._

GRUEN, DIETRICH—A Swiss watchmaker who with his son Fred first succeeded in making a very thin watch. The Gruen watch factory at Cincinnati, Ohio, is unique in this country. The buildings and surroundings resemble those of Switzerland, and the method of manufacture embodies more handwork than is common in the American system.

GRUET—A Swiss who introduced chains for the fusee instead of catgut cord, in 1664. They are still used for marine chronometers, some clocks, and the few fusee watches now made.

GUARD PIN—A pin in a lever escapement which prevents the pallets leaving the escape wheel when the hands of a watch are turned back. Also known as the "safety pin."

GUILD OR GILD—An association of people occupied in kindred pursuits for mutual protection and aid. Watch and clockmakers belonged to the Blacksmiths' Guild in England until 1631, when the Clockmakers' Company was formed. In France the Clockmakers' Guild was powerful in 1544.

HAIR-SPRING—Said by some to be a distinctly American term for the balance spring of a watch. But Wood (English) uses it in his "Curiosities of Clocks and Watches," 1866. However, it is not in common use outside of America. It is thought to have originated from the fact that in early times attempts were made to utilize hog-bristle for the balance spring.

HALF PLATE—A watch in which the top plate covers but half of the pillar plate, the fourth wheel pinion being carried in a cock to allow the use of a larger balance. Now obsolete or nearly so. Replaced by the bridge-model.

HALL MARK—A stamp placed upon gold and silver articles by government officials after the metal therein has been assayed.

HANDS—The metal pointers which, moved by the train, indicate the time by pointing to the figures on the dial. At present there are always two, the hour and minute hands and frequently a seconds hand also. Clocks at first were made with only the hour hand; the minute hand was introduced when the use of the pendulum made timekeeping sufficiently accurate for the indication of such small divisions.

HANGING BARREL—A going-barrel with its arbor supported only at the upper end.

HARRIS, RICHARD—An English clockmaker for whom it is claimed that he made the first pendulum clock—set up at St. Paul's, Covent Garden, in 1641. Most authorities agree, however, that this honor belongs to Huyghens.

HARRISON, JOHN—An English mechanician born at Faulby in Yorkshire in 1693. He made many improvements in the mechanism of clocks, the greatest of which was the compound pendulum. He won in 1761 a reward offered by Parliament in 1714 for an instrument that would determine longitude within thirty marine miles. Harrison's chronometer gave it within eighteen miles. He invented the going fusee, the gridiron compensation pendulum and suggested the idea for the compensation balance, afterward worked out by other watchmakers. Died 1776.

HAUTEFEUILLE, JOHN—(Abbe.) Born 1647. Died 1724. He disputed successfully Huyghens' claim to a prior invention of the steel balance spring. He is also credited with the invention about 1722 of the rack-lever escapement.

HEART-PIECE—The heart-shaped cam on the center-seconds wheel of a chronograph, which causes the hand to fly back to zero.

HELE, PETER—(See _Henlein, Peter_.) Some historians credit invention of first watch to Peter Hele. There is no doubt, however, that Hele and Henlein were one and the same. Preponderance of authority favors "Henlein" as the correct spelling of the name.

HELICAL—Following the course of a helix or spiral.

HELIOTROPION—See "_Polos_."

HEMICYCLE—Form of sun-dial in which the shadow of a vertical pointer or "gnomon" is cast upon and moves around the inner surface of a half globe or sphere. Supposed to have been invented about 350 B. C. (See _Sun-Dial_). Vitruvius, the Roman Engineer, ascribes invention to the Babylonian priest and astronomer, Berosus.

HENLEIN, PETER—Sometimes called Peter Hele. A clockmaker of Nuremberg, who is believed to have made the _first_ portable (pocket) clock or _watch_ sometime early in the sixteenth century. Born 1480. Died about 1540. His clock was round, driven by a spring and had small wheels of steel. It was much larger than present day watches.

HOLLOW PINION—A pinion bored through the center. The center pinion in many watches is hollow.

"HON-WOO-ET-LOW" OR COPPER JARS DROPPING WATER—A form of clepsydra at Canton, China, said to be between 3000 and 4000 years old. It consists of four copper jars arranged on steps. Each jar drops water into the one below it until the last one, in which a bamboo float, indicates the time in a rude way.

HOOKE, ROBERT, M. D.—An English physician-philosopher born on the Isle of Wight in 1635. His accomplishments were numerous. He claimed to have discovered the isochronism of the balance spring and its application to watches, though this was also claimed by Huyghens. He invented a pendulum timekeeper for finding the longitude at sea; devised the first wheel-cutting engine about 1670; and he invented the anchor escapement for clocks. His studies and inventions covered a wide field. He died in 1702.

HOROLOGE, (OROLOGE), (HOROLOGIUM)—A general term applied indiscriminately in old writings to any mechanism for measuring time.

HOROLOGICAL INSTITUTE—BRITISH—An association of watchmakers founded in 1858 for the purpose of advancing the horological arts.

HOROLOGICAL PERIODICALS, AMERICAN—American Jeweler, (Monthly), Chicago, Ill.; Goldsmith and Silversmith, (Monthly), New Haven, Conn.; Jeweler's Circular, (Weekly), New York,; Keystone (Monthly), Philadelphia, Pa.; Manufacturing Jeweler, Providence, R. I.; Mid-Continent Jeweler, Kansas City, Mo.; National Jeweler, (Monthly), Chicago, Ill.; Northwestern Jeweler, St. Paul, Minn.; Pacific Goldsmith, (Monthly), San Francisco, Cal.; Trader and Canadian Jeweler, Toronto, Canada.

HOROLOGIUM—See _Horologe_.

HOROLOGY-The science of time-measurement or of the construction of time pieces.

HOUR—Now consisting of sixty minutes or one twenty-fourth of an equinoctial day. Formerly one twelfth of the time between sunrise and sunset, and one twelfth of the time between sunset and sunrise; hence of different lengths for day and night in the different seasons. This required much adjustment of clocks; and automatic devices for such adjustment were in great demand. A standard hour of uniform length for all times and seasons was not adopted in Paris—the last place to change—until 1816.

HOUR-GLASS—A device for measuring hours. It has two cone-shaped superimposed glass globes connected at their apexes through a small opening. The glass contains just that quantity of sand, or mercury, as will flow in one hour through the opening from the upper globe to the lower. When it has run through the glass is reversed. See: _Sand Glass_. Like the sun-dial and the clepsydra, the hour-glass is older than we know. Its use probably followed close upon that of the clepsydra, or may even have preceded it in dry countries like Egypt and Babylonia, where sand was all about and water was not a thing to waste. Of its original forms there is no authentic record. Dry sand does not, like water, run faster or slower through a given opening according to the pressure from above; its rate is the same whether the upper glass is full or nearly empty. Also the hour-glass never needs to be refilled, but only to be reversed, and the same sand used over and over again. On the other hand, its convenience diminished as its size increased. It was too clumsy for use if made large enough to run without attention for more than an hour or two; and in so large a glass there was more danger that the sand, however dry, might cake up and stop running. It must somehow have been transparent for convenient reading, because sand can register the time only by its flow: it cannot be made to raise a float or work a pointer. But the Egyptians very early learned to manufacture glass, and there were other substances. A legend ascribes the invention of the sand-glass to Luitprand, a Carthusian monk of the Eighth Century A. D. But this, if there is any truth in the story at all, must have been some improvement or reinvention after the forgetfulness of the Dark Ages. The device is plainly shown in Greek sculptures antedating the Christian era. Nowadays the sand-glass has pretty much disappeared, except as a kitchen timepiece for boiling eggs and the like.

HOUR HAND—The hand of a watch or clock which indicates the hour: for long after clocks were first made, the only hand provided.

HOUR WHEEL—The wheel which revolves on the minute wheel or cannon pinion and carries the hour hand.

HOWARD, EDWARD—Born at Hingham, Mass., October 6, 1813. Having served a regular apprenticeship in clockmaking he entered into partnership with D. P. Davis, at the age of 29, to make clocks. He was a clever mechanic and invented many pieces of mechanism, among them the swing rest. In 1849 he and Davis with A. L. Dennison and others organized the American Horologe Company for the manufacture of watches by machinery, and with the parts interchangeable—the American principle of today. Though they were not financially successful the American watch industry owes its present day success largely to this beginning by Edward Howard and Aaron L. Dennison. The first company developed into the present Waltham Company, and later Mr. Howard established the E. Howard Co., at Roxbury, but severed his connection with them in 1882 and retired from business. He died March 5, 1904.

HUGGEFORD, IGNATIUS—An English watchmaker, one of whose watches was used to defraud Facio of his patent on the use of jewels in watches. See _Facio, Nicolas_.

HUNTER, OR HUNTING-CASE—A watch case which has a solid metal cover over the dial.

HUNTER, GEORGE—Identified with watchmaking in America since about 1860—in the Waltham and Elgin Companies. He was general superintendent of the latter from 1872 to 1903, after which he was made consulting superintendent.

HUYGHENS, CHRISTIAN—A celebrated Dutch astronomer and mathematician born at The Hague, April 14, 1629. Although the honor is claimed for Richard Harris in 1641 and for Vincent Galileo in 1649 it seems historically established that Huyghens in 1657 was the first to apply to clocks the theory of the isochronism of the pendulum which the great Galileo had discovered. In 1669 he published his important work, "Horologium Oscillatorium." In 1673 he made the first clock with concentric hour and minute hands. He died in 1695.

HUYGHENS' CHECKS—The arc of a swinging pendulum is a segment of a circle. For perfect isochronism it should be a cycloidal segment. To accomplish this Huyghens fixed curved brass pieces called checks for the cord to strike against but he caused thereby a greater error than he remedied. This end was later accomplished by suspending the pendulum by means of a flat steel strip instead of a cord; a device credited to Robert Hooke.

HYPOCYCLOID—A curve generated by any point in the circumference of a circle which is rolled on the inner side of the circumference of a larger fixed circle.

IDLER, IDLE WHEEL, OR INTERMEDIATE WHEEL—A toothed wheel used to connect driver and follower wheels so that both shall rotate in the same direction.

IMPULSE—The push transmitted to the pallet by the escape wheel.

IMPULSE PIN—The jewel pin—usually a ruby—on the table roller of the lever escapement, which playing into the fork of the lever transmits the impulse to the balance.

INDEPENDENT CENTER-SECONDS—A watch peculiarly adapted to the use of the medical profession. It carries on a separate train a long seconds hand in addition to the hands of the ordinary watch which can be stopped without stopping the watch.

INDEPENDENT SECONDS—A watch whose seconds hand is driven by a separate train.

INGERSOLL, CHARLES HENRY—Secretary, Treasurer and General Manager of Robt. H. Ingersoll & Bro., watch manufacturers, of New York City. Born at Delta, Eaton County, Michigan, October 29, 1865, a son of Orville Boudinot and Mary Elizabeth (Beers) Ingersoll. At the early age of fifteen years he left home and went to New York City, where he entered the employ of his brother, Robert H., who was then engaged in the business of manufacturing rubber stamps. Since 1880 he has been continuously associated with his brother in various business enterprises and in the direction and management of the Ingersoll organization. Married Eleanor Ramsey Bond of Brooklyn, New York, July 5, 1898. Residence, South Orange, New Jersey.

INGERSOLL, ROBERT HAWLEY—Founder and President of Robt. H. Ingersoll & Bro., watch manufacturers, of New York City. Born December 26, 1859, of Orville Boudinot and Mary Elizabeth (Beers) Ingersoll, at Delta, Eaton County, Michigan, he received his early education in the public schools of his native town. In 1879, at the age of nineteen years, he came to New York City, and in the following year engaged in the business of manufacturing rubber stamps; later, he established a mail order business, selling various "dollar" specialties and novelties. While engaged in this business he conceived the idea and in 1892 commenced the manufacture of the "dollar watch," since which time over 50,000,000 watches have been produced and sold by the Ingersoll organization. Married June 20, 1904, to Roberta Marie Bannister of Green Bay, Wisconsin. Residence, Oyster Bay, Long Island.

INGERSOLL, WILLIAM HARRISON—Marketing Manager of Robert H. Ingersoll & Bro., watch manufacturers, New York City. Born March 22, 1879, near Lansing, Michigan. He received a grammar and high school education and three years' technical training for electrical engineer. In 1901 he entered business in the retail sporting goods store of Robt. H. Ingersoll & Bro. in New York City and was soon placed in charge of the Ingersoll watch advertising, over which he exercised close supervision ever since, except for two periods prior to 1908, when he sought and gained valuable outside experience in other capacities, such as salesman and as manager of the Ingersoll watch business in Canada; he then became advertising manager, later sales and advertising manager and then general marketing manager for developing all markets of all countries of the world for the Ingersoll products. Active in the promotion of advertising research, Mr. Ingersoll was one of the founders of Truth in Advertising work, assisted in establishing a Fellowship in Advertising Research at Columbia University, New York City, and has written and lectured extensively on salesmanship, advertising, marketing and related subjects. His residence is at Maplewood, New Jersey.

INGOLD, FRANZ—A Swiss watchmaker who had the idea of making watch parts on the interchangeable plan long before it was put into practice anywhere. He was ill-received by labor and capital alike when he presented his plans in France, England, and America. In England he was nearly mobbed. In 1842-43 he obtained patents on some machinery in this line, but the machines were clumsy and for the most part impracticable. There has been a tendency to credit Ingold as the source of Dennison's ideas on this subject, though Dennison says he never heard of Ingold until after he had started manufacturing.

INTERCALARY—Introduced or added arbitrarily to a calendar; for example, the 29th day of February is an intercalary day.

INTERCHANGEABILITY—America's greatest contribution to watchmaking has been the standardizing of parts and the manufacturing of each of them, exactly alike, in great quantities. So that repairing an American watch is largely a matter of obtaining a new part similar to the damaged one, and simply putting it in place.

INVAR—An alloy of nickel and steel claimed to be non-magnetizable. Used for certain parts of watches at the time when non-magnetizable watches were desirable. Invar is practically non-expansible when the nickel in it is about 37%.

ISOCHRONISM—That property of a pendulum or balance spring by virtue of which its vibrations, of whatever length, are all made in exactly equal periods of time.

JACKS; OR JACK O' THE CLOCK—Figures on the old turret clocks which automatically struck the hours. They preceded dials tho were usually left when the dials were added. There are Jacks on the clock at St. Mary Steps, Exeter; Norwich Cathedral, South Aisle; and St. Dunstan's in Fleet St., among others.

JACQUEMARTS—Figures of man and woman which struck the hours on the clock set up by Philip of Burgundy at Dijon, prior to 1370. G. Peignot says they are so named from Jacquemart, a clock maker of Lille, employed by the Duke of Burgundy in 1442. The lack of co-ordination in the dates tends to controvert the claim.

JEROME, CHAUNCEY—Originator of the one-day brass clock movement which enormously increased the American clock business and opened a market for American clocks in Europe. Born in Canaan, Connecticut, in 1793. Established the Jerome Clock Company at New Haven, Connecticut. This was the predecessor of The New Haven Clock Company.

JEWELLED—Fitted with precious stones to diminish wear as distinguished from precious stones for ornament. In the best watches ruby and sapphire are used. In lower grade watches quartz, amethyst and garnet.

JEWELS—Used in watches as bushings at the ends of pivots and in other places which sustain much wear. They:

1. Provide smooth bearings for the
pivots.

2. Obviate corrosion.

3. Reduce the wear from abrasion.

Sapphire is the best of the jewels in use and ruby second. Chrysolite is also used and garnet, tho the latter is too brittle for most service. This use of jewels was invented by Nicolas Facio—a Swiss watchmaker about 1705.

JULIAN PERIOD—A period of 7980 years obtained by multiplying 28, 19 and 15—the numbers representing the cycles of the sun and moon, and the Roman Indiction. It will end 3267 A. D., until which time there cannot be two years having the same numbers for three cycles.

JURA MOUNTAINS—A watchmaking center in Switzerland. The industry grew rapidly following the success of Daniel Jean Richard in 1679. This section is the center of the system of watch-manufacturing most nearly like the American system. See _Geneva_.

JURGENSEN, JULES—One of the most famous watchmakers of the 19th century; a son of Urban Jurgensen, born in 1808. He studied physics, mechanics and astronomy in Paris and London and finally settled in Locle, Switzerland, specializing in pocket chronometers, which have become famous as the Jurgensen watches. He died in 1877; and was succeeded by his son, Jules F. U. Jurgensen.

JURGENSEN, URBAN—A Danish mathematician and watchmaker born in 1776. He practiced his trade for a time in Switzerland, worked in Paris under Breguet and Berthoud, and then in London, before returning to Copenhagen to enter into partnership with his father, the court watchmaker. He was made superintendent of all the chronometers of the Danish navy and received several decorations. He died in 1830.

KEW OBSERVATORY—The central meteorological observatory of the United Kingdom. Established at Richmond in 1842 and afterward transferred to the Royal Society. Since 1900 it has been a department of the National Laboratory. Important to the watch business because of the famous Kew tests of timekeepers and awards for accuracy of performance.

KEYLESS WATCHES—Watches winding without a key. Such watches were made as early as 1686 but did not come into general use until 1843, when Adrien Phillipe (Geneva) introduced the "shifting clutch" type, and when the "rocking bar" mechanism was introduced in 1855. These are the types in use today. Self-winding watches have been made from time to time. Napoleon is said to have had one which wound automatically from the motion of being carried. The abandonment of the key nullified the usefulness of the fusee, although some keyless fusee movements were attempted.

KNUCKLES—The rounded parts of a watchcase that form the hinges or joints. Usually two on the cover.

LA CHAUX DE FONDS—A watchmaking center in Switzerland which, in 1840, with a population of 9678, had 3109 watchmakers. At present it is the leading exporter of gold watches in Switzerland. In this section the system of manufacturing is much like the American system.

LAMINATED—Made up of tin sheets of beaten, rolled or pressed metal. In the compensation balance—the sheets are of brass and steel, or brass and aluminum.

LANCASTER, PA.—A town where there have been watch factories for upwards of fifty years.

LANGE, ADOLPH—An eminent Dresden watchmaker born there in 1815, famous for his astronomical clocks, chronometers, and fine watches. Under the direction and with the assistance of his government he established the extensive watchmaking industry of Glashutte. He died in 1875.

LANTERN PINION—A pinion consisting of two circular metal end plates usually of brass joined by short steel wires which act as cogs in a gear.

LATITUDE—1. In astronomy, the angular elevation of a heavenly body above the ecliptic. 2. In geography a distance measured in degrees, minutes and seconds north or south from the equator. 3. In dial work, the elevation of the pole of the heavens; the angle at which the plane of the horizon is cut by the earth's axis.

LEAD—The continuous action of a wheel tooth which impels the leaf of a pinion or the pallet of a balance.

LEAP-YEAR—See _Calendar, Gregorian_.

LEAVES—The name applied to the teeth of a pinion wheel.

LEPAUTE, J. A.—1709-1789. A French clockmaker famous for his turret clocks; the inventor of the pin-wheel escapement and an authoritative writer on horological subjects. He wrote "Traité d'Horlogerie" which was afterward revised and added to by Lalaude.

LEPIRE, JEAN ANTOINE—Born 1720. Died 1814. A celebrated watchmaker of Paris in the 18th century. About 1770 he introduced bars to take the place of a top plate, omitted the fusee, used a cylinder escapement and supported his mainspring barrel arbor at one end only. He attempted to establish a watch factory for Voltaire at Ferney but with no success. He is sometimes credited with making the first thin watch.

LE ROY, JULIEN—1686-1759. A French scientist and watchmaker. He invented the horizontal movement for turret clocks, a form of repeating mechanism. He constructed the first compensation balance.

LE ROY, PIERRE—1717-1785. Son of Julien Le Roy. Esteemed the greatest of all French horologists. He invented a form of duplex escapement and an escapement which formed the basis for the present chronometer escapement.

LEVER—That part of a lever escapement to which are attached the pallet arms, and which thus transmits motion from the escape wheel to the balance.

LIFT, OR LIFTING ARC—That portion of the oscillation of a balance during which it received its impulse. The remainder of the turn is called the supplementary arc.

LIGHTFOOT, PETER—A Glastonbury monk, maker of the Glastonbury and Wimburne clocks, 1335.

LIPS—In a cylinder escapement, the rounded edges of the cylinder through which the escape wheel gives impulse to the balance.

LOCKING—1. The stopping of the escape wheel of a watch or clock. 2. The portion of the pallet on which the teeth of the escape wheel drop. 3. The depth to which the escape tooth laps upon the pallet at the moment it leaves the impulse face.

LOGAN, JOHN—Born in Lowell, Mass., 1844. Invented a new method of tempering springs and made superior main and balance springs. He was connected for several years with the Waltham Watch Company, during which time he invented many labor-saving machines. Died 1893.

LONGITUDE—The circular distance east or west subtending the angle which two meridional planes make at the axis of the earth, one of them being a standard reference meridian.

LONGINES—A watch factory at St. Imier in the Jura Mountains, near La Chaux de Fonds, established in 1874. Here all parts are made under one roof and the work is done by machinery.

LOWER PLATE—The plate in a watch nearest the dial. Also called the "dial plate." It carries the lower pivots of the movement.

LUITPRAND—A monk of Chartres who revived the art of glass-blowing at the end of the 8th century. To him is sometimes ascribed the invention of the sand-glass.

LUMINOUS DIAL—A watch dial whose hands and figures are so treated as to be visible in the dark. Formerly accomplished by a phosphorescent paint which required frequent exposure to sunlight to be effective and retained its luminosity only an hour or two. Now effected by means of a compound absolutely independent of the sunlight and of a lasting glow. See _Radiolite_.

LUNETTE—The usual form of rounded watch crystal.

MAINSPRING—The long steel ribbon used for driving a clock or watch. The spring is coiled into a circular metal box called the barrel and the outer end of the spring is fastened to the barrel; the inner end to the arbor of the great wheel. First applied, replacing weights, by Peter Henlein of Nuremberg, about 1500.

MAINTAINING POWER—The device for driving the train while a watch or clock is being wound.

MARSH, E. A.—An important figure in watch manufacturing in America for a number of years. Born at Sunderland, Conn., in 1837, in 1863 he entered the employ of the Waltham Watch Company and rose to the position of General Superintendent. In 1908 he retired from active service but retains his connection with the company as consulting superintendent. Besides his practical services to the watchmaking industry Mr. Marsh wrote "The Evolution of Automat Machinery," in 1896.

MASSEY, EDWARD—An English watchmaker of the early nineteenth century. He invented the "crank roller" escapement, a kind of keyless winding for watches, and many other watch parts.

MEAN SOLAR DAY—The average length of all the solar days in a year. This period is divided into 24 parts, or hours.

MEAN TIME—Clocks, watches, etc., are made to measure equal units of time instead of the apparent time indicated by the sun. Mean time and true solar time agree only four times in a year. See _Equation of Time_.

MERCER'S BALANCE-A balance of the ordinary kind fitted with an auxiliary—a laminated arm of brass and steel fixed at one end to the central bar of the balance and on its free end carrying two adjustable screws. This auxiliary may be arranged for either extreme of temperature with great accuracy.

MERIDIAN DIAL—A dial for determining when the sun is on the meridian. It is very simply constructed. For directions see "Watch and Clockmakers' Handbook," by F. J. Britten.

MERIDIAN WATCH—A watch which shows the time in a number of places in different parts of the world. It is set to Greenwich time and marks the difference between this and the time of all the great metropolitan cities in both hemispheres.

METRONOME—An instrument for indicating and marking exact time music. It consists of a counterbalanced, or reversed, pendulum, which may be regulated to swing at any desired number of vibrations per minute.

MIDDLE TEMPERATURE ERROR—The compensation balance does not exactly meet the temperature error. The rim expands too much with decrease of temperature and contracts too little with the increase. Hence a watch or chronometer can be correctly adjusted for two points only. The unavoidable error between is the middle temperature error.

MINUTE—The sixtieth part of a mean solar hour.

MINUTE HAND—The hand on a clock or watch which indicates the minutes. In the earlier days clocks had no minute hand. It was first concentered with the hour hand in 1673.

MINUTE WHEEL—The wheel which carries the minute hand and is driven by the cannon pinion.

MINUTE WHEEL PIN OR STUD—The stud fixed to the plate on which the minute wheel pinion turns.

MINUTE WHEEL PINION OR "NUT"—The pinion in watches on which the minute wheel is mounted and which drives the hour wheel.

MOMENT OF INERTIA—The resistance of a body in motion (or at rest) to a change in the velocity or direction of its motion. In a rotating body the sum of the products formed by multiplying the mass of each particle by the square of its distance from an axis.

MONTH—An arbitrary division of the year, varying in the number of days it contains, according to the calendar in use. See _Calendar_.

MORTISE—A slot or hole into which a tenon of corresponding shape is to be fitted.

MOSELEY, C. S.—A pioneer in the field of designing and building automatic watchmaking machinery. He invented some of the most delicate and complicated tools and mechanisms used in watch manufacture. He was early connected with the Waltham Co., master mechanic for the Nashua Co., during its brief history; and later general superintendent of the Elgin National Watch Company.

MOTION—The wheels that carry the hands: cannon pinion, horn wheel and minute wheel and pinion.

MOTION WORK—The wheels in a watch which make the motion of the hour hand one twelfth as rapid as that of the minute hand.

MOVEMENT—The watch or clock complete, without dial or case—the mechanism of the watch or clock.

MUDGE, THOMAS—An English watchmaker of the 18th century. Born at Exeter in 1716, died 1794. In 1793 he received from Parliament three thousand pounds as a recompense for his improvements in chronometers. His work was celebrated for its excellence.

NAME BAR—The bar which carries the upper end of the arbor of a watch barrel.

NAVAL OBSERVATORY—The United States Naval Observatory at Washington, D. C. There is there a superlatively accurate clock from which the time is flashed electrically to all parts of the United States.