The history of watches began in 16th-century Europe, where watches evolved from portable spring-driven clocks, which first appeared in the 15th century.
The watch was developed by inventors and engineers from the 16th century to the mid-20th century as a mechanical device, powered by winding a mainspring which turned gears and then moved the hands; it kept time with a rotating balance wheel. In the 1960s the invention of the quartz watch which ran on electricity and kept time with a vibrating quartz crystal, proved a radical departure for the watchmaking industry. During the 1980s quartz watches took over the market from mechanical watches, a process referred to as the "quartz crisis". Although mechanical watches still sell in the watch market, the vast majority of watches have quartz movements.
One account of the origin of the word "watch" suggests that it came from the Old English word woecce which meant "watchman", because town watchmen used watches to keep track of their shifts. Another theory surmises that the term came from 17th-century sailors, who used the new mechanisms to time the length of their shipboard watches (duty shifts).
The Oxford English Dictionary records the word watch in association with a timepiece from at least as early as 1542.
Clock-watch
The first timepieces to be worn, made in the 16th century beginning in the German cities of Nuremberg and Augsburg, were transitional in size between clocks and watches. Portable timepieces were made possible by the invention of the mainspring in the early 15th century. Nuremberg clockmaker Peter Henlein (or Henle or Hele) (1485-1542) is often credited as the inventor of the watch. He was one of the first German craftsmen who made "clock-watches", ornamental timepieces worn as pendants, which were the first timepieces to be worn on the body. His fame is based on a passage by Johann Cochläus in 1511,From Cosmographia Pomponii Melae, 1511 Peter Hele, still a young man, fashions works which even the most learned mathematicians admire. He shapes many-wheeled clocks out of small bits of iron, which run and chime the hours without weights for forty hours, whether carried at the breast or in a handbag However, other German clockmakers were creating miniature timepieces during this period, and there is no evidence Henlein was the first.
These 'clock-watches' were fastened to clothing or worn on a chain around the neck. They were heavy drum-shaped cylindrical brass boxes several inches in diameter, engraved and ornamented. They had only an hour hand. The face was not covered with glass, but usually had a hinged brass cover, often decoratively pierced with grillwork so the time could be read without opening. The movement was made of iron or steel and held together with tapered pins and wedges, until screws began to be used after 1550. Many of the movements included striking or alarm mechanisms. They usually had to be wound twice a day. The shape later evolved into a rounded form; these were later called Nuremberg eggs. Still later in the century there was a trend for unusually shaped watches, and clock-watches shaped like books, animals, fruit, stars, flowers, insects, crosses, and even skulls (Death's head watches) were made.
These early clock-watches were not worn to tell the time. The accuracy of their verge and foliot movements was so poor, with errors of perhaps several hours per day, that they were practically useless. They were made as jewelry and novelties for the nobility, valued for their fine ornamentation, unusual shape, or intriguing mechanism, and accurate timekeeping was of very minor importance.Milham 1945, p.141
Pocket watch Styles changed in the 17th century and men began to wear watches in pockets instead of as pendants (the woman's watch remained a pendant into the 20th century). This is said to have occurred in 1675 when Charles II of England introduced waistcoats. This was not just a matter of fashion or prejudice; watches of the time were notoriously prone to fouling from exposure to the elements, and could only reliably be kept safe from harm if carried securely in the pocket. To fit in pockets, their shape evolved into the typical pocket watch shape, rounded and flattened with no sharp edges. Glass was used to cover the face beginning around 1610. Watch fobs began to be used, the name originating from the German word fuppe, a pocket. Later in the 1800s Prince Albert, the consort to Queen Victoria, introduced the 'Albert chain' accessory, designed to secure the pocket watch to the man's outergarment by way of a clip. The watch was wound and also set by opening the back and fitting a key to a square arbor, and turning it.
The timekeeping mechanism in these early pocket watches was the same one used in clocks, invented in the 13th century; the verge escapement which drove a foliot, a dumbbell shaped bar with weights on the ends, to oscillate back and forth. However, the mainspring introduced a source of error not present in weight-powered clocks. The force provided by a spring is not constant, but decreases as the spring unwinds. The rate of all timekeeping mechanisms is affected by changes in their drive force, but the primitive verge and foliot mechanism was especially sensitive to these changes, so early watches slowed down during their running period as the mainspring ran down. This problem, called lack of isochronism, plagued mechanical watches throughout their history.
Efforts to improve the accuracy of watches prior to 1657 focused on evening out the steep torque curve of the mainspring. Two devices to do this had appeared in the first clock-watches: the stackfreed and the fusee. The stackfreed, a spring-loaded cam on the mainspring shaft, added a lot of friction and was abandoned after about a century. The fusee was a much more lasting idea. A curving conical pulley with a chain wrapped around it attached to the mainspring barrel, it changed the leverage as the spring unwound, equalizing the drive force. Fusees became standard in all watches, and were used until the early 19th century. The foliot was also gradually replaced with the balance wheel, which had a higher moment of inertia for its size, allowing better timekeeping.
Balance spring
A great leap forward in accuracy occurred in 1657 with the addition of the balance spring to the balance wheel, an invention disputed both at the time and ever since between Robert Hooke and Christiaan Huygens. Prior to this, the only force limiting the back and forth motion of the balance wheel under the force of the escapement was the wheel's inertia. This caused the wheel's period to be very sensitive to the force of the mainspring. The balance spring made the balance wheel a harmonic oscillator, with a natural 'beat' resistant to disturbances. This increased watches' accuracy enormously, reducing error from perhaps several hours per dayMilham 1945, p.226 to perhaps 10 minutes per day, resulting in the addition of the minute hand to the face from around 1680 in Britain and 1700 in France. The increased accuracy of the balance wheel focused attention on errors caused by other parts of the movement, igniting a two century wave of watchmaking innovation.
The first thing to be improved was the escapement. The verge escapement was replaced in quality watches by the cylinder escapement, invented by Thomas Tompion in 1695 and further developed by George Graham in 1715. In Britain a few quality watches went to the duplex escapement, invented by Jean Baptiste Dutertre in 1724. The advantage of these escapements was that they only gave the balance wheel a short push in the middle of its swing, leaving it 'detached' from the escapement to swing back and forth undisturbed during most of its cycle.
During the same period, improvements in manufacturing such as the tooth-cutting machine devised by Robert Hooke allowed some increase in the volume of watch production, although finishing and assembling was still done by hand until well into the 19th century.
Temperature compensation and chronometers
The Enlightenment view of watches as scientific instruments brought rapid advances to their mechanisms. The development during this period of accurate marine chronometers required in celestial navigation to determine longitude during sea voyages produced many technological advances that were later used in watches. It was found that a major cause of error in balance wheel timepieces was changes in elasticity of the balance spring with temperature changes. This problem was solved by the bimetallic temperature compensated balance wheel invented in 1765 by Pierre Le Roy and improved by Thomas Earnshaw. This type of balance wheel had two semicircular arms made of a bimetallic construction. If the temperature rose, the arms bent inward slightly, causing the balance wheel to rotate faster back and forth, compensating for the slowing due to the weaker balance spring. This system, which could reduce temperature induced error to a few seconds per day, gradually began to be used in watches over the next hundred years.
The going barrel invented in 1760 by Jean-Antoine Lépine provided a more constant drive force over the watch's running period, and its adoption in the 19th century made the fusee obsolete. Complicated pocket chronometers and astronomical watches with many hands and functions were made during this period.
Lever escapement
The lever escapement, invented by Thomas Mudge in 1754 and improved by Josiah Emery in 1785, gradually came into use from about 1800 onwards, chiefly in Britain; it was also adopted by Abraham-Louis Breguet, but Swiss watchmakers (who by now were the chief suppliers of watches to most of Europe) mostly adhered to the cylinder until the 1860s. By about 1900, however, the lever was used in almost every watch made. In this escapement the escape wheel pushed on a T-shaped 'lever', which was unlocked as the balance wheel swung through its centre position and gave the wheel a brief push before releasing it. The advantages of the lever was that it allowed the balance wheel to swing completely free during most of its cycle; due to 'locking' and 'draw' its action was very precise; and it was self-starting, so if the balance wheel was stopped by a jar it would start again.
Jewel bearings, introduced in England in 1702 by the Swiss mathematician Nicolas Fatio de Duillier, also came into use for quality watches during this period. Watches of this period are characterised by their thinness. New innovations, such as the cylinder and lever escapements, allowed watches to become much thinner than they had previously been. This caused a change in style. The thick pocketwatches based on the verge movement went out of fashion and were only worn by the poor, and were derisively referred to as "onions" and "turnips".
Mass production At Vacheron Constantin, Geneva, Georges-Auguste Leschot (1800–1884), pioneered the field of interchangeability in clockmaking by the invention of various machine tools. In 1830 he designed an anchor escapement, which his student, Antoine Léchaud, later mass-produced. He also invented a pantograph, allowing some degree of standardisation and interchangeability of parts on watches fitted with the same calibre.