The Nashua Watch Company of Nashua, New Hampshire, was organized; it

failed in 1862 and was bought in by the American Watch Company—now The

Waltham Watch Company.

_1863_

The Newark Watch Company of Newark, New Jersey, was organized; it sold

out to The Cornell Watch Company of Chicago in 1870.

The United States Watch Company of Marion, New Jersey, was organized;

it failed in 1872 and was operated by creditors for a short time under

the name of The Marion Watch Company, but again failed; machinery of

the company was sold to E. F. Bowman of Lancaster, Pennsylvania, who

manufactured a few watches and then sold the business to The J. P.

Stevens Watch Company of Atlanta, Georgia.

_1864_

The National Watch Company was organized and erected a factory at

Elgin, Illinois; in 1874 the name was changed to its present name of

The Elgin National Watch Company.

The Tremont Watch Company of Boston was organized, with Aaron L.

Dennison, one of the founders of the original Waltham Watch Company as

superintendent; it ceased business in 1868 because of lack of capital;

machinery of the company was sold to an English syndicate which

organized in England The Anglo-American Watch Company, the name of

which was later changed to The English Watch Company.

The New York Watch Company of Springfield, Massachusetts, was

organized by Don J. Mozart and others; it practically failed in 1866

and was reorganized under the same name; again failed in 1870 and the

business was taken over by a new company known as The New York Watch

Manufacturing Company. This Company survived only a few months and the

property and business were taken over by a new group in January 1877

under the name of The Hampden Watch Company, which company, in turn,

was later purchased by John C. Deuber and associates in control of The

Deuber Watch Case Manufacturing Company of Canton, Ohio, which was

originally organized at Cincinnati about 1888.

_1867_

The Mozart Watch Company of Ann Arbor, Michigan, was organized by

Don J. Mozart after leaving The New York Watch Company; in 1871 the

property and business were sold to The Rock Island Watch Company of

Rock Island, Illinois.

_1869_

The Illinois Springfield Watch Company was organized; in 1875 it was

reorganized under the same name; in 1879 it was again reorganized and

the name was changed to The Springfield Illinois Watch Company, which

was later changed to The Illinois Watch Company, under which name it

now operates.

_1870_

The Cornell Watch Company of Chicago was organized and took over the

business of The Newark Watch Company of Newark, New Jersey; in 1874

it sold its business and property to The Cornell Watch Company of San

Francisco, California.

_1871_

The Rock Island Watch Company of Rock Island, Illinois, was organized

and purchased the business of The Mozart Watch Company of Ann Arbor,

Michigan; it failed the same year without producing any watches and

passed out of existence.

_1872_

The Washington Watch Company of Washington, D. C., was organized, but

failed after two years.

_1873_

The Rockford Watch Company of Rockford, Illinois, was organized; in

1896 the company failed and the business was operated by assignee until

1901 when it was sold and reorganized under the name of The Rockford

Watch Company, Ltd.; it discontinued business in 1915, since which

time the remaining stock has been marketed by The Illinois Watch Case

Company of Elgin, Illinois.

_1874_

The Adams & Perry Watch Manufacturing Company of Lancaster,

Pennsylvania, was organized; it failed in 1876 without producing any

watches; the property was purchased by a syndicate in 1877 which

organized under the name of The Lancaster Pennsylvania Watch Company;

in 1878 it was reorganized under the name of The Lancaster Pennsylvania

Watch Company, Limited; in 1878 it was again reorganized under the name

of The Lancaster Watch Company. In 1884 control of the company passed

to Abram Bitzner, who, with Oppenheimer Bros. & Vieth, selling agents

of New York City, began to operate the company and assumed the name of

"Keystone Watch Company" as a trade mark; they failed in 1890 and in

1892 the property was purchased by The Hamilton Watch Company.

The Freeport Watch Manufacturing Company of Freeport, Illinois, was

organized, but before producing any watches the company's factory

burned and the business was discontinued in 1875.

_1874_

The Cornell Watch Company of San Francisco, California, was organized

and took over the business of the Cornell Watch Company of Chicago; in

1875 the company was reorganized under the name of The California Watch

Company and in 1877 the business was sold to the Independent Watch

Company of Fredonia, New York.

_1875_

Fitchburg Watch Company of Fitchburg, Massachusetts, was organized, but

discontinued, for lack of funds, a few years later without producing

any watches.

_1877_

The Hampden Watch Company, now of Canton, Ohio, was organized at

Springfield, Massachusetts and took over the business of the New

York Watch Company; later, the Company's business and property were

purchased by the interests in control of the Deuber Watch Case

Manufacturing Company of Canton, Ohio.

The Independent Watch Company of Fredonia, New York, was organized and

purchased the business and property of the California Watch Company

of San Francisco; in 1885 the business was sold to the Peoria Watch

Company of Peoria, Illinois.

_1879_

The Auburndale Watch Company, of Auburndale, Massachusetts, was

organized and purchased the machinery of the United States Watch

Company of Marion, New Jersey. In 1883 the company made a voluntary

assignment.

_1880_

The Waterbury Watch Company of Waterbury, Connecticut, was

incorporated; in 1898 the name of the company was changed to the New

England Watch Company; in 1912 the company failed, and in 1914 the

property was sold to and is now operated as one of the factories of

Robt. H. Ingersoll & Bro. of New York City.

The E. Ingraham Company of Bristol, Connecticut, founded by E. Ingraham

in 1835 for the manufacture of clocks, was incorporated; in 1912 the

company purchased the business of The Bannatyne Watch Company of

Waterbury, Connecticut.

The Western Watch Company of Chicago was organized but failed the same

year without producing any watches, the machinery being sold to The

Illinois Watch Company.

_1882_

The Columbus Watch Company was organized at Columbus, Ohio; it was the

outgrowth of a private enterprise started in 1876 by D. Gruen and W. J.

Savage, who imported watch movements from Switzerland and sold them in

American-made cases. In 1903 the business of the company was purchased

by The South Bend Watch Company of South Bend, Indiana.

The J. P. Stevens Watch Company of Atlanta, Georgia, was organized and

failed in 1887.

_1883_

The New Haven Watch Company of New Haven, Connecticut, was organized;

in 1886 the company moved to Chambersburg, New Jersey, then a suburb

of Trenton; in the same year the name of the company was changed to

The Trenton Watch Company; in 1907 the company failed and in 1908 the

business and property were acquired by Robt. H. Ingersoll & Bro. of New

York City. The factory at Trenton has since been operated as one of the

plants of the Ingersolls.

The Manhattan Watch Company of New York City was organized but did not

long continue.

The Cheshire Watch Company of Cheshire, Connecticut, was organized and

continued in operation for about ten years.

The Aurora Watch Company of Aurora, Illinois, was incorporated but did

not begin operations until 1885; failed in 1886; machinery sold in 1892

to The Hamilton Watch Company of Lancaster, Pennsylvania.

_1884_

The Seth Thomas Clock Company of Thomastown, Connecticut, founded by

Seth Thomas in 1813 and incorporated in 1853, began the manufacturing

of watches in 1884, but discontinued their manufacture in 1914. Seth

E. Thomas, Jr., great-grandson of the founder, is now president of the

company.

The United States Watch Company of Waltham, Massachusetts, was

organized as an outgrowth of The Waltham Watch Tool Company. Later it

failed and its plant was purchased by The Keystone Watch Case Company,

which operates the factory under the name of The Howard Watch Company.

_1885_

The New York Standard Watch Company of Jersey City, New Jersey, was

organized; in 1902 it was purchased by The Keystone Watch Case Company,

which continues to operate it under the original name.

The Peoria Watch Company of Peoria, Illinois, was organized and took

over the business of The Independent Watch Company of Fredonia, New

York, but did not long survive.

_1887_

The Wichita Watch Company of Wichita, Kansas, was organized, but

continued in operation only a few years.

_1888_

The Western Clock Manufacturing Company was incorporated with factory

at Peru, Illinois, and general offices at La Salle, Illinois; began

manufacturing watches in 1895; in 1895 the name of the company was

changed to Western Clock Company; manufacturers of "Big Ben" alarm

clock and low-priced nickel watches.

_1890_

D. Gruen Sons & Co., of Cincinnati, originally incorporated under laws

of West Virginia; in 1898 re-incorporated under laws of Ohio. Prior to

original incorporation the business was operated as a partnership under

the name of D. Gruen & Sons. Present company also operates under the

trade name of Gruen Watch Case Co. The company manufactures its watch

movements in Switzerland, assembling and casing them in the United

States.

_1892_

The Hamilton Watch Company of Lancaster, Pennsylvania, was organized;

made only movements until 1909, but since then, both cases and

movements.

_1893_

Robt. H. Ingersoll & Bro., of New York City, first introduced the

original Ingersoll watch to the public at the World's Columbian

Exposition; in 1892 the Ingersolls had contracted with the Waterbury

Clock Company of Waterbury, Connecticut for the manufacture of the

low-priced watch, which was first sold for $1.50 and later for

$1.00; in 1908 the Ingersolls purchased the factory and business of

the Trenton Watch Company of Trenton, New Jersey, and began watch

manufacturing on their own account; in 1914 they purchased the plant of

The New England Watch Company, formerly The Waterbury Watch Company of

Waterbury, Connecticut.

_1894_

The Webb C. Ball Company of Cleveland, Ohio, founded in 1879 and

incorporated in 1891, began the manufacture of watches.

_1899_

The Keystone Watch Case Company of Philadelphia, Pennsylvania,

was organized. It controls The Howard Watch Company of Waltham,

Massachusetts, The New York Standard Watch Company of Jersey City, New

Jersey, The Crescent Watch Case Company, Inc., of Newark, New Jersey,

and The Philadelphia Watch Case Company of Riverside, New Jersey.

_1902_

The South Bend Watch Company of South Bend, Indiana, was incorporated

in New Jersey under the name of The American National Watch Company,

but immediately thereafter changed to its present name; in 1903 it

purchased the business of The Columbus Watch Company of Columbus, Ohio;

in 1913 it was re-incorporated under Indiana laws.

_1904_

The Ansonia Clock Company of Brooklyn, New York, incorporated in 1873,

began the manufacture of low-priced nickel watches; its principal

business, however, is that of clock manufacture.

_1911_

The Leonard Watch Company of Boston, Massachusetts, was incorporated

for the purpose of selling and distributing watches.

APPENDIX D

_Well-Known Watch Collections_

(From list compiled by Major Paul M. Chamberlain, of Chicago in 1915.)

ABBOTT—George E. H. Abbott, Groton, Massachusetts.

ADDINGTON—S. Addington, Esq., purchaser at Bernal sale.

ASHMOLEAN—Ashmolean Museum, Oxford, England.

AUGSBURG—Maxmillian Museum, Augsburg, Germany.

BAKER—Edwin P. Baker, referred to by Britten.

BAXTER—James Phinney Baxter, Portland, Maine.

BLOIS—Musee de la ville, Blois, France.

BOSTON—Museum of Fine Arts, Boston, Massachusetts.

BOURNE—T. W. Bourne, referred to by Britten.

BRITISH—British Museum, London, England.

BULLEY—Edward H. Bulley, referred to by Britten.

BURKHARDT—M. Albert Burkhardt, Basle, Switzerland.

CHAMBERLAIN—Paul M. Chamberlain, Chicago, Illinois.

CHESAM—Lord Chesam, referred to by Britten.

CLUNY—Musee de Cluny, Paris, France.

CLARKE—A. E. Clarke, London, England.

COCKEY—Edward C. Cockey, New York City.

COINTRE—La Famille Cointre, of Poitiers, France.

COPENHAGEN—Horological Museum, Copenhagen, Denmark.

COOK—E. E. Cook, Walton-on-Thames, England.

CZAR—Imperial collection, Hermitage Gallery, Petrograd, Russia

(1915).

CUMBERLAND—Duke of Cumberland, England.

DEBRUGE—Debruge collection, catalogue published in 1849,

referred to by M. E. Deville in Les Horlogers Blesois.

DENNISON—Franklin Dennison collection, Birmingham, England.

DEVOTION—The Edward Devotion House, Brookline, Massachusetts.

DICKSON—R. Eden Dickson, London, England.

DITISHEIM—Henri Ditisheim, Chaux-de-Fonds, Switzerland.

DRESDEN—Green Vaulted Chambers, Dresden, Germany.

DUPLESSIS—Family of Duplessis of Blois, referred to in Les

Horlogers Blesois.

DOVER—Dover Museum, Dover, England.

DUNWOODY—Dr. W. J. Dunwoody, mentioned by Britten.

ESTREICHER—Dr. Tad. Estreicher, Fribourg, Switzerland.

ESCHENBACH—Baroness Marie von Ebner-Eschenbach, Vienna,

Austria-Hungary.

FAWKES—J. H. Fawkes of Farnlet Hall, England.

FELLOWS—Collection of Sir Charles Fellows, of Westbourn, Isle

of Wight, bequeathed by widow to British Museum.

FITZWILLIAM—Fitzwilliam Museum, Cambridge, England.

FLEISHER—Collection of Moyer Fleisher, exhibited in the

Pennsylvania Museum, Memorial Hall, Philadelphia,

Pennsylvania.

FOULC—M. Foulc, Paris, France.

FRANCK—B. Bernard Franck, Paris, France.

FREEMAN—Charles Freeman, referred to by Britten.

FROIDEVAUX—M. Froidevaux, Blois, France.

GARNIER—M. Paul Garnier, Paris, France.

GELIS—M. Edouard Gelis, Paris, France.

GEYER—H. F. Geyer, mentioned by Britten.

GEORGI—M. Georgi, Paris, France.

GLYN—George Carr Glyn, referred to by Britten.

GOTHA—Museum of Gotha, Germany.

GREENE—T. Whitcomb Greene, referred to by Britten.

GUILDHALL—Guildhall Museum, London, England.

HARTSHORNE—Albert Hartshorne, referred to by Britten.

HEARN—George Hearn collection, presented by widow to

Metropolitan Museum of Art, New York City.

HECKSCHER—Martin Heckscher collection in Vienna,

Austria-Hungary.

HEINZ—Collection of Henry J. Heinz, exhibited in the Carnegie

Museum, Pittsburg.

HODGKINS—Collection of J. E. Hodgkins, London, England.

HUMPHREYS—Miss M. Humphreys, mentioned in Britten.

JENKINS—Collection of Jefferson D. Jenkins, Decatur, Illinois.

KING—C. King, Newport, Monmouthshire, England.

KENSINGTON—South Kensington Museum, London, England.

KIRNER—B. A. Kirner, Chicago, Illinois.

LAMBERT—Messrs. Lambert, referred to by Britten.

LAZERUS—Collection of Moses Lazerus, Philadelphia, bequeathed

to Pennsylvania Museum, Philadelphia, Pennsylvania.

LAMBILEY—Compte de Lambiley, France.

LAURANCE—E. A. Laurance, mentioned by Britten.

LEBENHEIM—Mentioned in Morgan catalogue.

LECOINTRE—Family of Lecointre, Poitiers, France.

LEICESTER—Leicester Museum, Leicester, England.

LEROUX—M. E. Leroux, Paris, France.

LILJIGREN—L. O. Liljigren, Chicago, Illinois.

LONDESBORO—Lord Londesboro, London, England.

LOUVRE—Musee de Louvre, Paris, France.

MARFELS—Collection of Carl Marfels, Berlin, Germany.

MASSEY—Edwards Massey, London, England.

MELDRUM—Robert Meldrum, referred to by Britten.

METROPOLITAN—Metropolitan Museum of Art, New York City.

MIRABAUD—M. G. Mirabaud, Paris, France.

MOORE—Bloomfield Moore collection in Pennsylvania Museum,

Philadelphia.

MORGAN—J. Pierpont Morgan collection at Metropolitan Museum of

Art, New York City.

O. MORGAN—Octavius Morgan collection in British Museum.

MORAY—Lord Moray, London, England.

MOSS—Rev. J. J. Moss, purchaser at Bernal sale, London,

England, 1855.

MUNICH—National Bavarian Museum at Munich, Germany.

NELTHROPP—Collection presented by Rev. H. L. Nelthropp to the

Worshipful Company of Clockmakers of the City of London

and exhibited at Guild Hall Museum.

NEWINGTON—Newington Free Library, Newington, England.

OLIVIER—M. Olivier, Paris, France.

PARR—Edward Parr, London, England.

PARTRIDGE—R. W. Partridge, London, England.

PONSONBY—Hon. Gerald Ponsonby, referred to by Britten.

PROCTOR—Frederick Towne Proctor, Utica, New York.

PROCTOR, T. R.—Thomas Redfield Proctor, Utica, New York.

PURNELL—J. B. Purnell, purchaser at Bernal sale in 1855.

RANKEN—William Ranken, London, England.

REEVES—R. F. Reeves, St. Louis, Missouri.

RENOUARD—Family of Renouard, Belois, France.

ROBERTS—Evan Roberts, London, England.

ROBERTSON—J. Drummond Robertson, London, England.

ROBLOT—Ch. Roblot, Paris—Passy, France.

ROTHCHILD—Baroness Alphonse de Rothchild collection.

ROSENHEIM—Max Rosenheim, referred to by Britten.

ROUX—Edward Roux, mentioned by Britten.

SALTING—Collection now in the South Kensington Museum.

SAUSSURE—M. Th. de Saussure, mentioned by Britten.

SAUVE—M. Sauve, Belois, France.

SCHLICHTING—Baron von Schlichting, Petrograd, Russia, (1915).

SHAPLAND—Charles Shapland, London, England.

SHAW—Morgan Shaw, London, England.

SIDEBOTTOM—Collection of Mrs. H. Sidebottom, in South

Kensington Museum.

SIVAN—M. Charles Sivan, Paris, France.

SMYTHIES—Major R. H. Raymond Smythies, London, England.

SOANE—Soane Museum, London, England.

STAMFORD—Stamford Institution, England.

STROEHLIN—Stroehlin collection, referred to in J. P. Morgan

catalogue.

SUDELL—Edward Sudell, mentioned by Britten.

SUTTON—Rev. A. F. Sutton, England.

THOMPSON—Mrs. G. F. Thompson, Ottawa, Canada.

TORPHICON—Lord Torphicon, referred to by Britten.

TURRETTINI—Turrettini collection referred to by Dr. Williamson

in Morgan catalogue.

VAUTIER—M. L. Vautier, Belois, France.

VENDOME—Calvaire de Vendome, France.

VIENNA—Imperial Treasury, Vienna, Austria-Hungary.

WALLACE—Lord Wallace collection, bequeathed by his widow to

the British Museum.

WEHRLE—Eugene Wehrle, Brussels, Belgium.

WHEELER, H. L.—Horace L. Wheeler, Boston, Massachusetts.

WHEELER—Collection of Willard H. Wheeler, Brooklyn, N. Y.,

exhibited in the Brooklyn Museum, New York City.

APPENDIX E

_Encyclopedic Dictionary_

ABRASION—Wearing away by rubbing or friction.

ADAMS, J. C.—A promoter instrumental in organizing the Elgin,

Illinois, Cornell, and Peoria Watch Companies, and the Adams & Perry

Manufacturing Company. He invented and patented the "Adams System"

of time records in use on most of the railroads in the West. He last

appeared in prominent connection with the watch and clock business as

the organizer of the Swiss horological exhibit at the World's Columbian

Exposition.

ADDENDA—Tips of the teeth of a wheel beyond the pitch circle. Sometimes

of circular outline; sometimes ogive—that is, of a shape patterned

after the pointed arch. The addendum is also known as the "face" of the

tooth.

ADJUSTMENT—The manipulation of the balance with its spring and staff to

secure the most accurate time-keeping possible. Three adjustments are

usually made, viz.: for isochronism, temperature and position. Much of

the difference in value and cost of watches depends on this operation.

ADJUSTMENT TO ISOCHRONISM—Strictly speaking this would cover all

adjustment; but it is technically understood to mean an adjustment of

the balance spring so that the time of vibration through the long and

short arcs of the balance is the same.

ADJUSTMENT TO POSITIONS—The manipulation of the balance and its spring

so that a watch keeps time in different positions. Good watches are

usually adjusted to five positions. They are pendant up; III up; IX up;

dial up; and dial down.

ADJUSTMENT TO TEMPERATURE OR COMPENSATION—The adjustment of the balance

and spring so that the time-keeping qualities are affected as little as

possible by changes in temperature. See _Compensation_.

AHAZ—King of Judea, 742-727 B. C. See _Dial of Ahaz_.

ALARM—Sometimes spelled "alarum." A mechanism attached to a clock

whereby at any desired time a bell is struck rapidly by a hammer.

ALUMINUM-BRONZE—An alloy of aluminum and pure copper, usually in the

proportion of 10 parts of the former and 90 of the latter. It is

considerably lighter than brass and highly resistant to wear.

ANAXIMANDER—Greek astronomer to whom the Greeks ascribed the invention

of the sun-dial in the sixth century B. C.

ARBOR—The axle or axis on which a wheel of a watch or clock turns. Also

applied to a spindle used by watchmakers.

ARC—Any section of the circumference of a circle.

ARCHIMEDES—A famous Greek philosopher and scientist sometimes credited

with the invention of the clock. About 200 B. C. he made a machine with

wheel work and a maintaining power but having no regulator it was no

better as a time teller than a planetarium turned by a handle. It may

have furnished the suggestion for later time-keeping machines.

ARNOLD, JOHN—Born 1736. An English watchmaker of note. He invented the

helical form of the balance spring and a form of chronometer escapement

much like Earnshaw's. Died 1799. Arnold's devices have been most useful

and permanent.

ASSEMBLING—The putting together of the finished parts of a watch. In a

three-quarter plate watch this is done on the lower plate. In a full

plate movement it is easier and more satisfactory to assemble on the

top plate.

ASTROLABE—1. An instrument of various forms formerly used especially

in navigation to measure the altitudes of planets and stars. 2. A

projection of a sphere upon any of its great circles.

ASTRONOMICAL TIME—Means solar time, as computed from observing the

passage of the sun across the meridian from noon of one day to noon

of the following day. It is counted continuously up to 24—not in two

12-hour divisions.

ASTRONOMY—The science which treats of the motions, real and apparent,

of the heavenly bodies. Upon this science, through its determination

of the length of the year, is founded the science of horology—or

time-keeping.

AUTOMATA—FOR STRIKING—Very common on old clocks and very

complicated, such as: Indian King hunting with elephants, Adam and Eve,

Christ's flagellation, and many others. See _Clocks, Interesting Old_.

AUTOMATIC MACHINERY—The second great contribution of America

to watchmaking after the establishment of the principle of

interchangeability of parts, and making possible the effective

execution of that principle.

AUXILIARY—A device attached to a compensation balance to reduce what is

known as the "middle temperature error." Some are constructed to act

in high temperatures only—as Molyneux's; and some in low temperatures

only—as Poole's.

BALANCE—The vibrating wheel in a watch or chronometer which with the

aid of the balance spring (hair-spring) regulates the rate of travel

of the hands. The balance is kept in vibration by means of the escape

wheel. See _Compensation Balance_.

BALANCE ARC—In detached escapements, that part of the vibration of

the balance in which it is connected with the train. The remainder is

called the drop.

BALANCE-CLOCK—A form of clock built before the pendulum came into use.

The regulating medium was a balance on the top of the clock made with a

verge escapement. See _Foliot_.

[Illustration: BALANCE COCK]

BALANCE COCK—The standard which supports the top pivot of the balance.

In old watches often elaborately pierced and engraved.

BALANCE SPRING—In America usually called the "hair-spring." A long

slender spring that governs the time of vibration of the balance. One

end of the balance spring is fastened to a collet fitted friction-tight

on the balance staff, the other to a stud attached to the balance cock

or to the watch plate. The most ordinary form is the volute, or flat

spiral. The other form used is an overcoil. See _Bréquet Spring_. The

principle of the isochronism of a balance spring was discovered by

Hooke, and first applied to a watch by Tompion. The name hair-spring

comes from the fact that the first ones are said to have been made from

hog bristles.

BALANCE SPRING BUCKLE OR "GUARD"—A small stud with a projecting tongue

attached to the index arm and bridging the curb pins so as to prevent

their engaging two of the balance spring coils. Used chiefly in Swiss

watches.

BALANCE STAFF—The axis of the balance. The part of a watch most likely

to be injured by a fall.

BALANCE WHEEL—A term often incorrectly applied to the balance itself,

but properly it is the escape wheel of the verge escapement.

BAND—Of a Watchcase—The "middle" of the case to which the dome, bottom

and bezel are fastened; the last sometimes screwed, sometimes snapped.

BANK—Banking-pin.

BANKING—In a lever watch the striking of the outside of the lever

by the impulse pin due to excessive vibration of the balance. In a

cylinder or verge movement the striking of the pin in the balance

against the fixed banking-pin.

BANKING-PIN—A pin for restricting the motion of the balance in verge

and cylinder watches.

BANKING-PINS—1. In a lever watch, two pins which limit the motion of

the lever. 2. In a pocket chronometer, two upright pins in the balance

arm which limit the motion of the balance spring. 3. In any watch,

the curb pins which confine the balance spring are sometimes called

banking-pins.

BARLOW, EDWARD (BOOTH)—A clergyman of the Church of England, born

in 1636. He devoted a great deal of time to horological pursuits.

He invented the rack repeating striking works for clocks, applied

by Tompion in 1676. He invented also a repeating works for watches

on the same plan. And he invented the cylinder escapement which he

patented with Tompion and Houghton. When he applied for a patent on his

repeating watch he was successfully contested by Quare, who was backed

by the Clockmakers' Company. He died in 1716.

BAR MOVEMENT—A watch movement in which bars take the place of the

top plate and carry the upper pivots. Sometimes termed a "skeleton"

movement. Not generally adopted because its many separate bearing parts

promote inaccuracies where large quantities are to be produced.

BARREL—A circular box which confines the mainspring of a watch or clock.

BARREL ARBOR—The axis of the barrel around which the mainspring is

coiled.

BARREL HOLLOW—A sink cut either into the top plate or the pillar plate

of a watch to allow the barrel freedom.

BARREL HOOK—A bent pin in the barrel to which the mainspring is

attached.

BARREL RATCHET—A wheel on the barrel arbor which is prevented by a dog

from turning backward while the mainspring is being wound and which

becomes the base against whose resistance the train is driven.

BARTLETT, P. S.—One of the early watchmakers of America. Connected

with the Waltham factory at first and later with the Elgin Company. It

is said that he first proposed the formation of the company at Elgin.

His name became familiar as a household word throughout the country

from being inscribed upon a full-plate model which attained widespread

success.

BEAT—The strike or blow of the escape wheel upon the pallet or locking

device.

BEAT PINS—The pins at the ends of the pallets in a gravity escapement

which give impulse to the pendulum.

BECKETT, SIR EDMUND—See _Denison, Edmund Beckett_.

BEROSUS—A Chaldean historian who lived at the time of Alexander the

Great, about 200 B. C., and was a priest of Belus at Babylon. Said

to have been the inventor of the hollow sun-dial. He was the great

astronomer of his age.

BERTHOUD, FERDINAND, 1727-1807— An eminent French watchmaker and

writer on horological subjects. Among his books are: "Essai sur

l'Horlogerie," "Traite des Horloges Marines," and "Histoire de la

mesure du Temps." He was a Swiss by birth, but lived most of his life

in Paris.

BEZEL—The ring of a watch or clock case which carries the glass or

crystal in an internal groove.

BIG BEN—The great bell which strikes the hours on the clock at

Westminster.

BIZZLE—A corruption of Bezel. See _Bezel_.

BLOW HOLES—Places where the brass and steel of a compensation balance

are not perfectly united, when they are put together with silver or

solder.

BOB—The metal mass forming the body of a pendulum.

BOETHIUS, ANCIUS MANLIUS SEVERINUS, A. D. 480-524—A Roman philosopher

and statesman to whom is sometimes attributed the invention of the

clock. He did make a sun-dial and a water clock which latter may have

contained a germ of the idea later developed into our modern clock.

BOSS—A cylindrical prominence or stud. The minute hand is carried on

the boss of the center wheel.

BOTTOM—Of a Watchcase—The cover outside the dome of the case. Commonly

called the "back."

BOUCHON—The hard brass tubing of which pivot holes in watch and clock

plates are made; known commonly as "bushing wire." The short sections

cut off for a pivot being called the "bushing."

BOW—The ring of a watch case to which the guard or chain is attached;

also known as "pendant bow."

[Illustration: BOW AND BUTTON]

BOX CHRONOMETER—A marine chronometer.

BOXING-IN—Fitting the watch movement in its case; applied chiefly to

the encasing of stem-winding movements.

BRÉQUET, ABRAHAM LOUIS—A celebrated Swiss mechanician and watchmaker

born at Neufchatel in 1747. He made several improvements in watches,

the most notable being the Bréquet hairspring still in use in the best

watches. He died in 1823.

[Illustration: BRÉQUET SPRING]

BRÉQUET SPRING—A form of balance spring which is a volute with its

outer end bent up above the plane of the body of the spring and carried

in a long curve towards the center near which it is fixed. Like all

other springs in which the outer coil returns towards the center, it

offers opportunities of obtaining isochronism by varying the character

of the curves described by the outer coil and thus altering its

resistance. So-called from its inventor, Abraham Louis Bréquet (q.

v.). Its advantage over the flat spring is that the overcoil allows

expansion and contraction in all directions, thereby avoiding a good

deal of side friction on the pivots as well as insuring more nearly

perfect isochronism in changes of temperature.

BRIDGE—A standard fastened to the plate, in which a pivot works.

BRIDGE MODEL—The term given to watch movements in which plates or

bridges carrying the upper pivots of the train rest firmly on the lower

or dial plate and are held rigid by steady pins on lower side of the

plate; the bridge being secured direct to the dial plate by screws

termed plate or bridge screws. This is the most common construction

of present-day manufacture and is utilized in three-quarter plate or

separate and combination bridges covering one or more pivots of train

wheels. Its alternate is "pillar model."

BUCK, D. A. A.—A watch repairer in Worcester, Mass., who designed a

model for the Waterbury watch. His first model was not successful, but

in 1877 he completed one which, a little later, the Waterbury Company,

with Buck as master watchmaker, started to make. He remained with the

company until 1884.

BUSH—A perforated piece of metal let into a plate to receive the wear

of pivots.

BUTTING—The engaging of the tips of the teeth of two wheels acting in

gear. The proper point of contact being in the line of the shoulders of

the teeth, butting is remedied by setting the wheels farther apart.

BUTTON—The milled knob used for winding and setting a keyless watch.

CALCULAGRAPH—Trade name for a device for automatically computing and

recording elapsed time in connection with factory jobs and other work

where it is necessary to show the amount of labor used.

CALENDAR—A system of dividing the year into months and days. The

principal calendars known to history are: the Julian calendar; the

Gregorian calendar; the Hebrew calendar; the Mohammedan calendar;

and the Republican calendar. None of them has been quite accurate in

dividing up the solar year, and frequent arbitrary corrections are

necessary to secure a practical approximation. See descriptive article

under each title.

_Julian_—Established by Julius Caesar, 46 B.C., to remedy existing

defects in the Roman calendar then in use. The Julian year was based on

the assumption that the solar year is 365¼ days—which was 11 minutes

and 14 seconds too long. The scheme adopted was to make the regular

calendar year 365 days, and to add one day every fourth year. The

Julian calendar is still in use by Russia and Greece, where the dates

now differ from those of most other countries by 13 days.

_Gregorian_—Established October 15, 1582, by Pope Gregory XIII, in

correction of the obvious errors of the Julian calendar. It is the

calendar now in use by nearly all civilized nations. The mean length of

the Gregorian year is 365 days, 5 hours, 49 minutes and 12 seconds—26

seconds longer than the actual solar year. Correction is made by adding

a 29th day for February every fourth year, excepting when the date of

said fourth year is divisible by 100. If, however, the date is also

divisible by 400, the extra day is added.

_Republican_—The calendar of the French Revolution (1793) declared to

begin at midnight on the meridian of the Paris Observatory preceding

the true autumnal equinox, September 22, 1792. There were 12 months of

30 days each and 5 or 6 "extra days" (as might be necessary) at the end

of the year to bring the new year nearest to the then position of the

equinox. Abolished January 1, 1806.

_Hebrew_—Composed of 12 lunar months, a thirteenth month being added

from time to time to secure correspondence of the months with

the passing seasons. The months are arbitrarily arranged to have

alternately 29 days and 30 days. The length of the calendar year varies

from 353 days to 385 days.

_Mohammedan_—Based on a lunar year of 354 days divided into 12 lunar

months which are alternately 29 and 30 days in length. During each

period of 30 years a total of 11 days are added one at a time at the

end of a year. The lack of co-ordination with the solar year results in

a total separation of the seasonal year and the calendar year. In use

in Turkey and some other Mohammedan countries.

[Illustration: CALENDAR CLOCK]

CALENDAR CLOCK, OR WATCH—A clock or watch which indicates days and

months as well as hours.

CALIPER—The scheme of arrangement of a watch train, or the disposition

of the parts of a watch.

[Illustration: CAM]

CAM—A rotating piece either non-circular or eccentric, used to

convert rotary into linear reciprocating motion, oftener irregular in

direction, rate, or time.

CANNON PINION—The pinion to which the minute hand is attached. It is

tubular in form (whence its name), the main arbor passing through it

friction-tight.

CANTON BERNE—The Swiss district which does the largest export business

in silver and base metal watches in Switzerland. The cantonal

government has done everything possible to promote the industry, among

other things: 1. Established information offices in the principal

watch-making centers. 2. Established a permanent exhibition of

articles used in the industry. 3. Established schools and associations

and protective territories. 4. Prepared statistics and means for

negotiating commercial relations.

CAP—The part of the case that covers the movement.

CAPPED JEWEL—A jewel having a protective end-stone.

CARILLON—Chimes frequently used in the earlier clocks for striking the

hours. Still used in some clocks.

CARON, PETER AUGUSTUS—A famous Paris watchmaker, afterward called

Beaumarchais, who made the first keyless watch of which we have any

account.

CASE—The metal box in which the movement of a watch is inclosed.

CASE-SPRINGS—The springs which cause the outer bottom of a watch case

to fly open when the lock spring is released.

CENTER OF GYRATION—That point in which the whole mass of a rotating

body might be concentrated without altering its moment of inertia.

CENTER OF OSCILLATION—That point in a pendulum at which, if the whole

mass of the pendulum were collected, the time of oscillation would be

the same.

CENTER SECONDS OR SWEEP SECONDS—A long seconds hand moved from the

center of a watch dial, as are the minute and hour hands.

CENTER STAFF—The arbor attached to the center wheel which carries the

minute hand.

CENTER WHEEL—The wheel in ordinary clocks and watches placed in the

center of the frame on whose arbor the minute hand is carried. It is

intermediate between the barrel and the third wheel.

CHAMFER—To cut away to a bevel the right angle formed by two adjacent

faces as of a jewel or stone. It is also occasionally used to signify

channeling or grooving.

[Illustration: CHAMFER]

CHASING—A form of ornament for metals which is made by punching or

pressing from behind to present the pattern in relief instead of by

cutting away the material.

CHOPS—In a pendulum clock the blocks, usually of brass, between which

the top of the pendulum suspension spring is clipped to prevent its

twisting as it swings.

CHRONOGRAPH—In general, a recording clock or watch. Specifically, a

watch with a center-seconds hand which may be stopped, started or

returned to zero at will by pressing a button. Used for timing races,

or measuring other short spaces of time with great exactness.

CHRONOMETER—Any very accurate time-keeper. Usually understood to mean a

time-keeper fitted with a spring detent escapement. They usually have a

fusee and a cylindrical balance spring.

CHRONOMETER, MARINE—Probably the most exact form of time-keeper,

especially for use on shipboard. The driving power is a mainspring

acting by a chain on a fusee, and governed by what is known as the

Chronometer or Detent Escapement, with, as a rule, the cylindrical

balance spring. The movement is mounted on gimbals in an air and

water-tight brass case, maintaining the dial constantly in a horizontal

position.

CHRONOSCOPE—A clock or watch in which the time is shown by figures

presented at openings in the dial.

CHURCH, DUANE H.—Credited with having contributed more to the automatic

features of watch machinery than any other man. He was born in Madison

County, N. Y., in 1849. At 16 he was apprenticed to a watchmaker of St.

Paul, Minn., and after working at the trade for 17 years, he became

in 1882 the master watchmaker for the Waltham Watch Company. Besides

his invaluable contributions to automatic machinery, he improved the

general design of watch movements and invented a form of pendant

setting which enables stem-winding movements to be set in cases not

especially adapted to them. He died in 1905.

CIRCULAR ERROR—The difference in time arising from the swinging of a

pendulum in a circular arc instead of its true theoretical path which

is a cycloidal arc. This caused much trouble in the early clocks.

Huyghens attempted to correct it (see _Huyghens' Checks_) but found

that his device caused greater error. With the heavier pendulum and

shorter arcs of vibration this error becomes negligible. The suspension

of the pendulum by a flat flexible spring instead of a cord, attributed

to Dr. Hooke, served to make the path practically cycloidal.

CLEOPATRA'S NEEDLE—An Egyptian obelisk at whose base a dial was marked.

Now in London. Another similar obelisk from Egypt is in Central Park,

New York City.

CLEPSAMMIA—The sand-glass, more familiarly known as the hour-glass. See

_Hour-glass_; _Sand-glass_.

[Illustration: CLEPSYDRA]

CLEPSYDRA—A device for the measurement of time by the flow of running

water. Its simplest form is a vessel filled with water which trickles

or drops slowly from a small aperture into another vessel. One or the

other of the vessels is graduated and the height of the water in that

one at any given time indicates the hour. Sometimes a figure floating

on the water points to the hours. Later, falling, or running, water

was made to turn wheels or to move a drum, as in "Vailly's clock."

Clepsydras were made and improved up to the 17th century. The earliest

known example—one in China—is credited with having existed in 4000

B. C. The name indicates the stealing away of water and is derived

from two Greek words meaning "water" and "to steal." A common form of

clepsydra in India was a copper bowl with a small hole in the bottom

floating on water. When the bowl filled and sank the attendant emptied

it, struck the hour upon it and floated it again on the surface of the

water. Like the sun-dial, the clepsydra was invented so long ago that

there is no authentic record of its origin. Its evident advantages

are exactly those which the sun-dial lacked. It is quite independent

of day or night or other external conditions; it is conveniently made

portable; and by regulating the size of the aperture through which

the water flows, it can be made to work slow or fast so as, within

considerable limits, to measure accurately and legibly long or short

intervals of time.

The disadvantages of the clepsydra were, first, that the hole in the

container tended to become worn away so as to let the water out too

fast; and second, that the water ran faster from a full vessel than

from one nearly empty, because of the greater pressure. This latter

was in classic times corrected by a clepsydra consisting of two

vessels. The second and larger of these was placed below, the water

running _into_ it, out of the first. A float within this larger vessel

rose regularly as it filled, and carried a pointer which marked the

time. The first vessel from which the water ran into the second, was

provided with an overflow, and kept constantly full up to this level;

so that the flow of water into the larger vessel remained constant.

[Illustration]

Once well established and understood in principle, the clepsydra

became widely known over the ancient world, and underwent a variety

of improvements and modifications in form. These latter chiefly dealt

with making it more legible. Means were devised, for instance, to

make it ring a bell when the water reached a certain height. And

thus the alarm principle was very early brought into use. Later on,

after the development of mechanical devices like the pulley and the

toothed wheel or gear, the pointer was by these means constructed to

move faster or slower than the rate at which the water rose, or to

revolve upon a circular dial on which the hours were marked. And thus

we owe to the clepsydra the origin of the modern clockface as well as

of the alarm. Later still, by a more complex ingenuity, devices were

arranged to strike the hours or to move mechanical figures, in fact,

to perform all the functions of a clockwork which was both driven and

regulated by hydraulic power. The single hour hand, however, remained

in place of our two or three hands moving at different speeds, as in

the modern clock or watch. The clockwork also remained primitive in

construction compared with our own. Clepsydrae were always expensive,

because accurate mechanical work was never cheapened until modern time.

Rather they were made marvels of patient ingenuity and lavish ornament.

Cunning oriental craftsmen spent their skill upon elaborate mechanism

and costly decorations. The clepsydra thus became first what other

time-pieces later became—a triumph of the jeweler's craft—a gift for

kings. And the Greeks, who beautified everything that they touched,

made it at once more accurate and more artistic.

The clepsydra may thus fairly claim to have been the first _mechanical_

device for measuring time, as contrasted with the sun-dial which was

really an astronomical instrument; and thus the direct ancestor of

the mechanical clocks of later days. Some authorities, indeed, on the

strength of certain very ancient allusions to its use in China and

elsewhere, claim for it an antiquity prior to the sun-dial itself.

There seems, however, to be no reason for supposing that the discovery

of a mechanical law like the regular flow of water antedated so

obvious a discovery as the motion of a shadow upon the ground. The

explanation is probably that the invention of the clepsydra did precede

the scientific perfecting of the sun-dial by the inclinations of the

gnomon; which may have taken place about the time of the correction of

the Babylonian calendar in 747 B. C. Not long after this date we meet

with frequent references to the placing of a clepsydra in the public

square of some old city, or to its use in astronomical calculations.

To this, of course, its property of running by night was peculiarly

adapted.

Although the chief defects of the clepsydra were minimized by the use

of the two vessels and by making the aperture through which the water

ran of gold or some other substance which would wear away very slowly,

yet there remained certain minor imperfections. The water could not be

kept entirely from evaporating; it had to be emptied out at intervals

and the reservoir refilled; its accuracy was affected by the expansion

of the parts under change of temperature, or it might even freeze.

These faults were obviated in the sand-glass or hour-glass which for

short intervals of time was also more convenient.

The clepsydra remained in use until clocks became superior to it in

accuracy. See _Clocks, Interesting Old_; _Charlemagne_; _Vailly_.

CLERKENWELL—A district on the north side of the city of London within

the metropolitan borough of Finsbury. It is distinguished as one of the

great centers of the watchmaking and jewelers' industries in England

and long established there. The Northampton Polytechnic Institute,

Northampton Square, has a department devoted to instruction in all

branches of the trade.

CLICK—The click, pawl, or dog, is a necessary accessory of a ratchet

wheel. It is a finger, one end of which fits into the teeth of the

ratchet, while the other is pivoted on its tangent. The ratchet is thus

prevented from turning backward.

CLOCK—Specifically, a time-piece not made to be carried about but to

stand upon a shelf or table, hang upon a wall or as built into a tower.

Formerly the term signified particularly a time-piece which struck

the hours. The word has its origin in the word for _bell_ in Latin,

_gloccio_; Teutonic, _glocke_; French, _cloche_; and Saxon, _clugga_.

At one time the term was used to denote timekeepers driven by weights

as distinguished from those driven by springs.

CLOCK-WATCH—A watch which strikes the hours in succession, as

distinguished from repeaters. Popular in the eighteenth century.

[Illustration: CLOCK-BANJO]

CLOCK, BANJO--A wall clock, so called from its shape, designed by Simon

Willard, of Massachusetts and very popular in its time.

[Illustration: CLOCK, BIRD-CAGE]

CLOCK, BIRD-CAGE—An old form of English clock whose manufacture has

been discontinued—it is the oldest form of English clock still doing

service. Its main feature is the endless chain drive. These clocks run

thirty hours.

CLOCK, BRACKET—A form of clock very popular in England during the reign

of Charles II, made to stand on a bracket or table and intended to be

seen from all sides. These clocks had either a handle on top or one on

each side. They were very beautifully finished.

CLOCK, CANDLE—Wax or tallow candle, usually twelve inches long and

marked with circular lines one inch apart. The candle would burn one

inch every twenty minutes or three inches an hour. Invention credited

to King Alfred the Great.

CLOCK, GRANDFATHER'S OR LONG-CASE—A tall clock with an anchor

escapement popular thru-out the later 18th and early 19th centuries in

England and America. Its excellent timekeeping qualities are due to the

very long and heavy pendulum which allows a small arc of vibration. Not

often made at present.

[Illustration]

CLOCK, HOOD—A style of clock originating and very popular in Holland

during the late 17th century. Made of various woods, carved and

ornamented and named from the hood or dome on top.

CLOCK, LAMP—A long glass tube upright on a metal stand similar in shape

to the old Roman lamps. Figures were painted on the tube to indicate

the hours—"12" in the middle section, with "11" above and "1" below

the "12." The lamp was filled with oil up to the hour at which it was

lighted—then as the oil burned away the time was indicated. This form

of clock was used at night in Dutch and German rural homes until a

comparatively recent date.

[Illustration]

CLOCK, LANTERN—Same as Bird-Cage Clock.

CLOCK, LARGEST IN WORLD—The Colgate clock in Jersey City is claimed to

be twice as large as the next largest clock in the world. Its dial can

be read for four miles and weighs six tons. Its minute hand is twenty

feet long and the tip of it travels more than half a mile per day.

[Illustration]

CLOCK MYSTERIES—Glass Dial—A perfectly transparent dial behind which no

movement was visible. The hands were caused to revolve by watch works

and semi-circular weights in the counterpoise of the hands.

CLOCK, OLDEST IN AMERICA—A clock owned by the Philadelphia Public

Library—over two centuries old. It was made in London and is said to

have been owned by Oliver Cromwell.

CLOCK, SHEEP'S-HEAD—A clock similar to the bird-cage or lantern clock

in which the dial face projects an inch or two beyond the frame.

CLOCK, SKELETON—A clock whose works are covered with glass as a

protection from dust, but are without a case, the works being exposed

to view. There are eight skeleton clocks in the Charles Mifflin Hammond

collection at the Essex Institute in Salem, Massachusetts.

CLOCK, TURRET—A large clock in which the dials are distinct from the

movement. Because of the exposure of the hands to the wind and snow,

of the clock to dust and dirt, and of the oil to freezing temperature,

turret clocks to keep time must be fitted with some device to obtain a

constant force on the pendulum. The first used was the remontoire but

since the invention of the gravity escapement for the Westminster clock

by Sir Edmund Beckett this has been used instead.

[Illustration]

CLOCK, "WAG ON THE WALL"—A wall clock typical of the North of Holland

in which weights and pendulum hung below the clock case, entirely

unenclosed.

CLOCK AND WATCH MAKERS, ENGLISH, EARLY—For extensive lists, dates,

places, and notes, see: Old Clocks and Watches & Their Makers, by

Frederick J. Britten; Worshipful Company of Clockmakers, London,

Published by E. J. Francis and Co., London, 1875; Old Clock Book, by

Mrs. N. H. Moore.

FRENCH, EARLY—See: Old Clocks and Watches and Their Makers, by F. J.

Britten.

SCOTTISH, EARLY—For extensive list with dates, places and notes, see:

Old Scottish Clock Makers, by John Smith.

CLOCK MAKERS, AMERICAN, EARLY—For lists, dates, places, and notes, see:

Old Clock Book, by Mrs. N. H. Moore; American Clockmaking—Its Early

History, by Henry Terry.

CLOCK MYSTERIES; TORTOISE IN WATER—Nicholas Grollier during the first

part of the eighteenth century made many mysterious timekeepers. One

was a metal dish filled with water in which floated the figure of a

tortoise always keeping his nose to the correct time.

BALL OF VENICE—This was a sphere—its upper and lower parts gold, and

about the middle a silver band bearing the numerals. As the band

revolved a Cupid's wing pointed to the hour. Its action was simple.

The cord which suspended it was wound about a cylinder. The weight of

the ball constituted the driving power. It had a verge escapement. The

maker is not known.

DOUBLE GLOBE—Constructed of two clear glass globes, the smaller one for

the minutes above the larger hour globe. The mechanism for the latter

was in the base, and for the minute globe, in the cap of the hour

globe. Made by Henri Cunge.

[Illustration]

CLOCKS, INTERESTING OLD: _Anne Boleyn's_—A clock said to have been

presented to Anne Boleyn by Henry VIII on their wedding morning. It is

about four inches square and ten inches high, of silver gilt "richly

chased, engraved, and ornamented." The weights are of lead covered with

copper, gilt and engraved. On one are Henry's and Anne's initials, and

true lovers' knots. On the other simply H. A. At the top of each weight

is "Dieu et mon droit," at the bottom "The most happye." On the top

of the clock is the figure of a lion holding the arms of England, the

same being engraved on the sides. The clock is now silent. There is no

record as to its maker.

_Canterbury_—This was the third of the large clocks in England. It was

constructed in 1292.

_Charlemagne's_—In 807 the King of Persia sent Charlemagne a bronze

water clock inlaid with gold. The dial consisted of twelve small doors

representing the hours. Each door opened at the hour it represented

and the correct number of balls fell out upon a brass bell. At twelve

o'clock twelve horsemen appeared and shut the doors.

_Coblentz_—At Coblentz in a tower on the Kaufhaus is a brazen head

which gnashes its teeth as the hours strike. For a Coblentzer to say

"How is the man in the Kaufhaus" means "How goes it with Coblentz and

the good people there?"

[Illustration]

_de Vick's_—In 1364 Henry de Vick set up a clock in the tower of the

palace for Charles V. It was regulated by a balance. The teeth of the

crown wheel acted upon two small levers called pallets which projected

from and formed part of an upright spindle or staff on which was fixed

the balance. The clock was regulated by shifting the weights placed at

each end of the balance. On the bell of this clock the signal for the

massacre of St. Bartholomew's was struck.

_Dondi's at Pavia_—Built in 1344, by James Dondi, similar to

Wallingford's clock.

_Exeter_—A clock built in Exeter Cathedral sometime in the 14th

century. One erected there in 1480 has the sun—a fleur-de-lis which

points out the hours as it revolves around a globe representing the

earth. A black and white ball represents the moon's phases by turning

on its axis.

_Frederick II_—The Saladin of Egypt presented Frederick II of Germany

with a clock in the year 1232. It resembled internally, a celestial

globe, in which figures of the sun, moon, and other planets moved

impelled by weights and wheels. There were also the twelve signs of the

Zodiac which moved with the firmament.

[Illustration]

_Hans von Jena's_—An old clock in Saxony at the top of which is a very

ugly head. As the clock strikes a pilgrim offers an apple on a stick

to the open mouth and then withdraws it. At the same time an angel

opposite the pilgrim raises her eyes from her book. The legend goes

that Hans von Jena, for a crime, was condemned to undergo such torture

for three centuries.

_Jefferson's_—An old weight clock in which the weights are carried over

a pulley and made to indicate the day of the week by their position.

This is in the hallway at Monticello.

_Lists and Descriptions of_—See Curiosities of Clocks and Watches, E.

J. Wood. Old Clocks and Watches and their Makers, F. J. Britten. Old

Clock Book, N. H. Moore.

[Illustration]

_Vase Clocks of Marie Antoinette_—The movement was inclosed in a marble

pedestal. About the beautifully tinted porcelain urn was a double band,

on which were marked the numerals and which revolved every twelve

hours. A serpent with head erect pointed to the hour.

[Illustration]

_Mary, Queen of Scots_—Skull Watch or Clock. A small clock in the

form of a skull said to have been given by Mary, Queen of Scots, to

Mary Seaton, one of her maids of honor. The skull is of silver gilt

and is engraved with figures of Death, Time, Adam and Eve, and the

Crucifixion. The lower part of the skull is pierced to emit the sound

when it strikes, being cut in the form of emblems of the Crucifixion.

The works occupy the brain's position in the skull fitting into a

silver bell which fills the entire hollow of the skull. The hours are

struck on this bell by a small hammer on a separate train.

POPE SIXTUS'—Built by Habrecht of Strasburg in 1589. It greatly

resembles the Strasburg clock which Habrecht also built. It was in

the possession of the Popes for more than two centuries and later

became the property of William I, King of the Netherlands. In 1850 it

was exhibited in England after which it became the property of Mr. O.

Morgan. It performs all the feats of the Strasburg clock.

_Rouen_—In the Rue de la Grosse Horloge in Rouen a clock made by Jehan

de Fealius in 1389 is built in a tower which surmounts an arched

gateway. Its dial is about six feet square. It shows the hours, days of

the week, and phases of the moon. It still keeps excellent time and is

the chief clock of the city.

[Illustration]

_St. Dunstan's_—Erected in 1671 above the gateway of the old St.

Dunstan's Church. The clock had two dials, back to back upheld by a

quaint bracket. In a little open belfry above were the gaily painted

figures of Gog and Magog which struck the quarters on bells suspended

near them. In 1830 the clock was sold to the Marquis of Hertford who

set it up at his home in Regent Park.

_St. Paul's_—A clock existed prior to 1298 in the tower of St. Paul's

Cathedral which struck the hours by means of mechanical figures called

Paul's Jacks. Later a fine dial was added.

_Strasburg_—Rebuilt twice after the first one which was begun about

1352. This first clock consisted of a calendar which showed the

principal movable feasts. It showed also the movements of the sun and

moon. On the upper part was a statue of the Virgin before which at noon

the figures of the three Magi bowed. At the same time a cock automaton

opened its beak, flapped its wings and crowed. 2. The second Strasburg

clock was erected about 1570. This was a very elaborate mechanism,

showing besides the time, a calendar for a century, the movements of

the sun and moon, eclipses of the same and other things. The striking

was done by an elaborate automatic arrangement. (See Old Clocks and

Watches & Their Makers—F. J. Britten.) 3. In 1842 the clock was again

thoroughly reconstructed. This, too, is a very elaborate system of

motions showing the movements of sun, moon, and planets, also sidereal

time, a calendar, etc. The hours and quarters are struck by automatic

figures.

_Ulm_—In the eastern end of the old Rathaus at Ulm is installed an

astronomical clock which dates from the beginning of the 16th century.

It was thoroughly repaired in 1549 by the builder of the Strasburg

clock—Isak Habrecht. Shows in addition to the hours, the diurnal and

annual revolutions of the earth and the movements and phases of the

moon. The clock is an artistic achievement as well as a mechanical

wonder.

_Vally's_—A scientific water clock. It consisted of a tin cylinder

divided into several small cells and suspended by a thread fixed to

its axis, in a frame on which the hour distances fixed by trial were

marked. It was so made that the water passed slowly from one cell to

the next and as it did so it changed the center of gravity of the

cylinder and set it in motion so as to indicate the time on the frame.

Made about 1690.

_Wallingford's_—Built in 1326 in St. Alban's Monastery. It showed

besides the hours, the apparent motion of the sun, the ebb and flow

of tides, changes of moon, etc. It continued to run until the time of

Henry VIII. Held by some to have been a mere planetarium.

_Wells Cathedral_—Clock built by Peter Lightfoot, A. D. 1340 at

Glastonbury and removed to Wells Cathedral during the Reformation,

after the dissolution of the Glastonbury monastery. In 1835 it was

again removed to the South Kensington museum. At that time the worn-out

works were replaced by a new train, but the dial and knights were

retained. The dial is divided into twenty-four hours and shows the

motion of the sun and moon. On its summit are eight armed knights

tilting at one another, lance at rest by a double rotary motion.

_Westminster_—A clock said to have been erected at Westminster with the

proceeds of a fine imposed upon one of the Chief Justices about 1288.

About 1365 Edward III had a stone clock tower erected at Westminster.

This tower contained a clock which struck the hours on a great bell.

It also contained other bells. This tower was razed by the Roundhead

mob about 1650. Later a dial with the motto "Discite justiam monite"

was placed on the site. The bell "Great Tom" was given to St. Paul's

about the beginning of the 18th Century. The present Westminster clock

is made after plans by E. B. Denison (Sir Edmund Beckett) and made by

E. J. Dent. The bell is called "Big Ben." It is claimed to be the best

timekeeper of its kind in the world. It was for use in this clock that

Denison invented his gravity escapement.

_Wimborne_—A very old clock at Wimborne in Dorsetshire, much like the

Wells Cathedral clock. By some authorities believed also to have been

planned by Peter Lightfoot.

CLOCK-SETTERS—During the early history of turret clocks, for each one

was employed a caretaker called the "setter." That such an official was

needed indicates that they were more or less undependable.

COCK—A horizontal bracket. See: _Balance Cock_; _Escape Cock_;

_Pendulum Cock_; _Potance_.

COLLET—A collar or flange on a cylindrical piece of metal. Any part of

such cylinder of greater diameter than the rest. Sometimes of the same

piece of metal; sometimes fitted friction tight upon it.

COMPENSATION—The provision made in a clock or watch to counteract the

expansion and contraction due to variations of temperature. In the

clock it is applied to the pendulum; in the watch to the balance.

[Illustration]

COMPENSATION BALANCE—A balance corrected for errors caused by

variations in temperature. The type in most general use was invented

by Thomas Earnshaw in the second half of the 18th century. The double

rim of this balance is constructed of brass and steel soldered together

in the form of a cut ring, the brass on the outside. When heat,

elongating the balance ring, causes it to vibrate more slowly, the

brass, expanding more than the steel, bends the free ends of the cut

rim toward the center, thus decreasing the diameter of the balance and

quickening the vibration. On the other hand, when cold, contracting the

ring tends to quicken the vibration of the balance, the contraction of

the brass rim draws the free end outward, making the diameter larger

and the vibration slower in consequence. The compensation balance is

also made with brass as the inner metal and aluminum outside.

COMPENSATION CURB—A laminated bar of brass and steel or aluminum and

brass fixed at one end, the free end carrying the curb pins that

regulate the length of the balance spring. Common in old watches but

not now in use.

COMPENSATION PENDULUM—A pendulum so constructed that the distance

between the point of suspension and the center of oscillation remains

constant in all temperatures. See: _Pendulum, Gridiron and Pendulum,

Mercurial Compensation_.

[Illustration]

CONTRATE WHEEL—A wheel whose cogs are parallel to its axis and whose

axis is at right angles to the axis of the wheel into which it gears. A

crown wheel.

CORROSION—The eating or wearing away of metals by slow degrees through

chemical action.

COUNTERSINK—To enlarge the outer end of a hole for the reception of the

head of a screw, bolt, etc. The term is also applied to the tool with

which the countersink is formed.

COVENTRY—A municipal, county, and parliamentary borough of

Warwickshire, England. One of the important watchmaking centers of

Great Britain.

CROWN WHEEL—A wheel whose teeth project at right angles to the plane of

the wheel. A contrate wheel. The escape wheel of the verge escapement

is an illustration.

CRUTCH—A light rod in a clock descending from the pallet arbor and

ending in a fork which embraces the pendulum rod. It transmits the

motion of the pallet to the pendulum.

CTESIBUS—A famous Greek mechanician who lived in Alexandria about 130

B. C. Although his was not the first clepsydra as is claimed by some it

was an ingenious and interesting one. Believed to have first applied

toothed wheels to clepsydrae about 140 B. C.

CURB PINS—See _Banking Pins_.

CUSIN, CHARLES—A watchmaker from Autun, Burgundy, who laid the

foundation for the Swiss watch industry in Geneva in 1587. It grew

very slowly at first—in 1687 having only one hundred watchmakers with

three hundred assistants. In 1760 there were at Geneva eight hundred

watchmakers with 5,000 to 6,000 assistants.

CUSTER, JACOB D.—(1809-1879.) A Pennsylvania clockmaker in 1831; he was

one of the early makers of watches in America in 1840. However, his

work was not important commercially, for he produced only about a dozen

watches. A very ingenious man, who, it is said, made everything from a

steam engine to his own shoes. He made hundreds of the clock movements

which at that period were used to revolve the lanterns in lighthouses.

CYCLE OF THE SUN—A period of twenty-eight years, after which the days

of the week again fall on the same days of the month as during the

first year of the former cycle. It has no relation to the sun's course

but was invented for the purpose of finding out the days of the month

on which the Sundays fall during each year of the cycle. Cycles of the

sun date from nine years before the Christian era.

CYCLOID—A curve generated by a given point in the circumference of a

circle which is rolled along a straight line always in the same place.

Example: The curve traced by any point in the rim of a wheel which

travels in a straight line along a level road.

CYLINDER ESCAPEMENT—See: _Escapement, Cylinder_.

CYLINDER PLUGS—Plugs fitted into the ends of the cylinder of a cylinder

escapement. Their outer extremities are formed into the pivots on which

the cylinder rotates.

DAMASKEEN—To decorate a metal by inlaying other metals or jewels, or by

etching designs upon its surface. To be distinguished from snailing,

with which it is often confounded.

[Illustration]

DAY—The time of one complete revolution of the earth on its axis.

The actual length of this day is continually changing owing to the

eccentricity of the earth's orbit and the angle of the ecliptic. The

mean solar day is 24 hours. The sidereal day is 23 hours, 56 minutes,

4.099 seconds.

DAY, NAUTICAL—The nautical day begins when the sun is on the meridian

and eight bells are struck. The day is divided into "afternoon watch"

or four hours, two "dog watches" of two hours each, then "middle

watch," "night watch," "morning watch" and "forenoon watch," each of

four hours, completing the day.

DENISON, EDMUND BECKETT—Sir Edmund Beckett—Lord Grimthorpe. Born 1816.

A lawyer by profession, and the inventor of the gravity escapement for

turret clocks; also an authoritative writer on horological subjects.

He designed and planned the Westminster clock said to be the best

timekeeper of its kind in the world. Died 1905.

DENNISON, AARON L.—Born in Freeport, Me., in 1812. Died Birmingham,

England, January 9, 1898. At eighteen he was apprenticed to a

watchmaker. Later in working at the trade, he was impressed with the

inaccuracies which existed in the best handmade watches. This, with

a visit to the Springfield Armory, gave him his idea of machine-made

watches with interchangeable parts. He interested Edward Howard in

the project, and having found the needed capital they started in the

business and laid the foundation of what is now the Waltham Watch

Company. Dennison has been called the "father of American Watchmaking"

tho there seems ground for the claim that he shares that honor with

Edward Howard.

DEPTHING—The technical name for the proper adjusting or spacing of the

gearing in a watch.

DETENT—The device which halts, and releases, at the proper instant the

escapement of a clock or chronometer. See: _Escapement_.

DE VICK, DE WYCK, OR DE WIECK, HENRY—A German clockmaker who, in

1364, made the first turret clock of which reliable information and

description remains. The clock was made for Charles V. See: _Clocks,

Interesting Old—De Vick's_.

DIAL—Commonly called the face of the watch—made of gold or silver or

other metal or of enamel, with the required figures—in the United

States one to twelve upon it in a contrasting color. See also,

_Sun-dial_.

DIAL FEET—Short wires soldered to the back of the dial of a watch or

clock which hold it in place by fitting into holes in the pillar plate.

DIAL OF AHAZ—A sun-dial belonging to Ahaz, King of Judea 742-727 B.

C., mention of which occurs twice in the Scriptures—II Kings, XX:

9-11, and Isaiah XXXVIII: 8. It is believed that one of his Babylonian

astrologers constructed it for him.

DIAL PLATE—See _Lower Plate_.

DIAL, SUN—See _Sun-dial_.

DIAL WHEELS—The wheels constituting the motion work of a watch.

DIURNAL—In an astronomical sense, pertaining to a period covering a

mean solar day. See: _Solar Time_.

DOG SCREW—A screw with an eccentric head used to attach a watch

movement to a dome case.

DOG-WATCH—A nautical term for two daily two-hour periods of watching

aboard ship. The first begins at 4 P. M., the other at 6 P. M.

DOLMEN—A sacred instrument used for astronomical purposes at certain

critical periods of the year; formed of four stones at the cardinal

points and a leaning stone crossing diagonally and forming with the

east stone a sacred "creep-way." The solar hours were indicated by the

shadow of the leaning stone touching various prominent points or edges.

One at Camp, England, is prehistoric.

DOME—The inner case of a watch which snaps on the band of a case.

DOME-CASE—A case in which the inner case or dome snaps to the band of

the case.

DONDI, GIACOMO—Born at Padua, Italy, in 1298. In 1344 he set up at

Padua a famous clock which became a model for later clocks and which

earned for him the surname, "Orologio."

DOUBLE BOTTOM CASE—A watch case in which the inner cover or bottom is

made solid with the middle. The vogue in English cases for a long time;

now almost obsolete.

DOUBLE-SUNK DIAL—A dial in which there are two sinks; one for the hour

hand, and a deeper one for the seconds hand.

DRAW—1. The force which holds the lever against its bank, due chiefly

to the angle of the locking face of the pallet stone. 2. The angle of

the locking faces of pallets in the lever escapement.

DRIVER—Of two wheels working together, the one which imparts the power.

The driven wheel is termed the follower.

DRIVING WHEEL—In a clock the wheel on the main arbor which drives the

whole train.

DROP—That part of the motion of the escape wheel when it is not in

contact with the pallet.

DRUM—The cylinder, or barrel, on the main arbor in a clock on which the

driving cord winds, raising the weight, when the clock is being wound.

DUMMY WATCH—(Fausse Montre.) About 1770 it became the fashion to wear

two watches. But because two real watches were too expensive for most

people, the custom grew up for having one sham watch—usually worn on

the right side. These were called "dummy watches" or "fausse montres."

EARNSHAW, THOMAS—1749-1829. An eminent English watchmaker who invented

the spring detent escapement and the compensation balance, both

essentially the same as are now used in chronometers. He first soldered

brass and steel together for the balance instead of riveting them.

EAST, EDWARD—Watchmaker to Charles I and an eminent horologist.

He was one of the ten original assistants named in the charter of

the Clockmakers' Company and at once took a leading part in their

proceedings. He was elected master in 1664 and 1682. He was the only

treasurer ever appointed by that company. He died probably about 1693.

East's watches were often presented as prizes by Charles in tennis

tournaments.

EDWARD VI—King of England from 1546 to 1553. Said to have been the

first Englishman to wear a watch.

ELECTRIC CLOCK—A clock in which the pallets moved electrically from a

distant mechanism drive the escape wheel and the hands.

ECLIPTIC—That plane passing through the center of the sun in which lies

the orbit of the earth. Also used to designate the apparent path of the

sun in the heavens.

ELGIN—A city in Illinois, U. S. A., in which is located the Elgin

National Watch Company—one of the largest factories in the United

States.

END-SHAKE—Freedom of pivots to move endways. Necessary in a watch or

clock because there is no force to spare and a tight pivot would stop

the movement.

END-STONE—A small disc of jewel against which the end of a pivot sets.

See _Capped Jewel_.

END-STOP—In a watch the same as end-stone.

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.

[Illustration]

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.

[Illustration]

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.

[Illustration]

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.

[Illustration]

[Illustration]

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.

[Illustration]

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.

[Illustration]

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_.

[Illustration]

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_.

[Illustration]

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.

[Illustration]

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.

[Illustration]

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.

[Illustration]