<P> 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". </P> <P> 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 . </P> <P> 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 . </P> <P> 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 . </P>

When was the first watch or clock invented