Watches evolved from portable spring driven clocks, which first appeared in 15th-century Europe. 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 craftsman who made “clock-watches” (taschenuhr), 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:
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.
The watch which developed in the 16th century was a mechanical device, powered by winding a mainspring which turned gears which moved the hands, and kept time with a rotating balance wheel. Most of the subsequent 500-year history of watches was devoted to refining the mechanical watch. The invention of the quartz watch in the 1960s, which ran on electricity and kept time with a vibrating quartz crystal, proved a radical departure for the industry. During the 1980s quartz watches took over the market from mechanical watches, an event referred to as the “quartz crisis”. Although mechanical watches still sell at the high end of the market, the vast majority of watches now have quartz movements.
One account of the origin of the word “watch” is that it came from the Old English word woecce which meant “watchman”, because it was used by town watchmen to keep track of their shifts. Another says that the term came from 17th century sailors, who used the new mechanisms to time the length of their shipboard watches (duty shifts).
Clock-watches
The earliest dated watch known, from 1530
The first timepieces to be worn, made in the 16th century in the German cities of Nuremberg and Augsburg, were transitional in size between clocks and watches.[8] 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 alarmmechanisms. 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.
Pocketwatches
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. To fit in pockets, their shape evolved into the typical pocketwatch 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 small pocket. 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 pocketwatches 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 mainspringintroduced 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 foliotmechanism 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
Drawing of one of his first balance springs, attached to a balance wheel, by Christiaan Huygens, inventor of the balance spring, published in his letter in the Journal des Sçavants of 25 February 1675
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 day 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.
Temperature compensation and chronometers
Diagram of Earnshaw’s standard chronometer detent escapement
The Enlightenment view of watches as scientific instruments brought rapid advances to their mechanisms. The development during this period of accurate marine chronometers 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
Thomas Mudge, inventor of the lever escapement
The lever escapement, invented by Thomas Mudge in 1759 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 center 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 1702 by Nicolas Fatio de Duillier in England, 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.
The British had predominated in watch manufacture for much of the 17th and 18th centuries, but maintained a system of production that was geared towards high quality products for the elite. Although there was an attempt to modernise clock manufacture with mass production techniques and the application of duplicating tools and machinery by the British Watch Company in 1843, it was in the United States that this system took off. Aaron Lufkin Dennison started a factory in 1851 in Massachusetts that used interchangeable parts, and by 1861 was running a successful enterprise incorporated as the Waltham Watch Company.
The railroads’ stringent requirements for accurate watches to safely schedule trains drove improvements in accuracy. The engineer Webb C. Ball, established around 1891 the first precision standards and a reliable timepiece inspection system for Railroad chronometers. Temperature compensated balance wheels began to be widely used in watches during this period, and jewel bearings became almost universal. Techniques for adjusting the balance spring for isochronism and positional errors discovered by Abraham-Louis Breguet, M. Phillips, and L. Lossier were adopted. The first international watch precision contest took place in 1876, during the International Centennial Exposition in Philadelphia (the winning four top watches, which outclassed all competitors, had been randomly selected out of the mass production line), on display was also the first fully automatic screw making machine. By 1900, with these advances, the accuracy of quality watches, properly adjusted, topped out at a few seconds per day.
The American clock industry, with scores of companies located in Connecticut’s Naugatuck Valley, was producing millions of clocks, earning the region the nickname, “Switzerland of America”. [18] The Waterbury Clock Company was one of the largest producers for both domestic sales and export, primarily to Europe. Today its successor, Timex Group USA, Inc. is the only remaining watch company in the region.
From about 1860, key winding was replaced by keyless winding, where the watch was wound by turning the crown. The pin pallet escapement, an inexpensive version of the lever escapement invented in 1876 by Georges Frederic Roskopf was used in cheap mass-produced watches, which allowed ordinary workers to own a watch for the first time; other cheap watches used a simplified version of the duplex escapement, developed by Daniel Buck in the 1870s.
During the 20th century, the mechanical design of the watch became standardized, and advances were made in materials, tolerances, and production methods. The bimetallic temperature compensated balance wheel was made obsolete by the discovery of low-thermal-coefficient alloys invar and elinvar. A balance wheel of invar with a spring of elinvar was almost unaffected by temperature changes, so it replaced the complicated temperature compensated balance. The discovery in 1903 of a process to produce artificial sapphire made jewelling cheap. Bridge construction superseded 3/4 plate construction.
Watches 