Time Telling through the Ages

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 (#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 (#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.

Neuchatel – A town in the Jura Mountains' watch manufacturing district of Switzerland. A Cantonal Observatory at Neuchatel helps establish the reputation for the accuracy of Swiss watches.

Non-Magnetic Watch – A watch in which the quick-moving parts – lever, pallets, balance spring, etc., are made of some other metal besides steel – as aluminum bronze, invar, etc.

Nuremberg – A German city where Peter Henlein made the first watch. It was one of the chief clock centers of the 16th and 17th centuries and with Augsburg and Ulm supplied the markets of Europe with the first small clocks.

Nuremberg Eggs – Watches made in Nuremberg in the shape of eggs. If not the first watches at least very early examples.

Obelisk – A square shaft with a pyramidal top. The ancient Egyptian obelisks are thought to have served as gnomons.

Ogive – A pointed arch – of the architectural type known as Gothic.

Oil Sink – The cavity around the pivot hole in watch and clock plates, designed to hold a small particle of oil in contact with the pivot.

Ormolu – Gilt or bronzed metallic ware, or a fine bronze which has the appearance of being gilded. Used for ornamenting the cases of fine old clocks.

Orologe – An obsolete form of horologe. See Horologe (#Horologe).

Orologiers – An obsolete form of horologers, a term not now in use but signifying men who constructed time-pieces.

Orrery – A planetarium; an instrument showing the relative motions, positions and masses of the sun and planets. It was so named from Lord Orrery, for whom the first modern planetarium was made in England.

Oscillation – The movement back and forward of a pendulum or the swing of a balance spring. The vibration.

Overbanking – Pushing of the ruby pin past the lever, caused by excessive vibration of the balance. In a cylinder escapement the turning back of the cylinder until an escape wheel tooth catches and holds it. In a chronometer escapement the second unlocking of the escape wheel from the same cause.

Overcoil – The outermost coil of a Breguet spring which is bent back across the coil toward the center.

Pacificus – Archdeacon of Verona, died about 850 A.D. It is claimed by some that he made a clock furnished with an escapement. (Bailly.) But this is not proved, and others believe it to have been merely a water-clock.

Pad – The pallet of the anchor escapement for clocks.

Pair Case – At one time watches were made with two or even three separate cases. The outer one of shagreen tortoise shell, or some other ornamental material was sometimes for the protection of the delicate enamel on the inner case. Sometimes as in the case of repeaters the inner case was pierced to emit the sound. Then the outer one served as dust protection to the works.

Palladium – A soft metal formerly used in alloy with copper and silver for the balance and balance spring of non-magnetizable watches. Too soft to be as serviceable as steel, it has been superseded by a platinum alloy.

Pallet – Has different meanings, even among watchmakers. Generally, the part through which the escape wheel gives impulse to the balance or pendulum.

Pallet Staff – The arbor on which the pallet is mounted, and on which it turns.

Pallet Stone – The jewel on the contact face of the pallet, where it is struck by the teeth of the escape wheel.

Parallax – The apparent angular displacement of a heavenly body due to a change of the observer's position.

Pedometer – An instrument which registers the number of paces walked – hence if properly adjusted to the length of step of the wearer it gives the distance traversed.

Pendant – The small neck and knob of metal connecting the bow of a watch case with the band of the case.

Pendulum – A body suspended by a rod or cord and free to swing to and fro; used in clocks to regulate the velocity with which the driving power moves the wheels and hence the hands. The isochronism of a pendulum vibrating in a cycloidal arc was first discovered by Galileo but he did not apply it to clocks. Most authorities credit Christian Huyghens with that adaptation to instruments for keeping time. The pendulum was first suspended by a silk cord and thus vibrated in a circular instead of cycloidal arc. "Huyghens' Checks" were an unsuccessful attempt to remedy this. Dr. Hooke succeeded in remedying it by suspending the pendulum by a flat ribbon of spring steel.