Watches evolved from portable Spring Driven clocks, which first appeared in 15th century Europe. Watches were not widely worn in pockets until the 17th century. One account says that the word “watch” came from the Old English word woecce which meant “watchman”, because it was used by town watchmen to keep track of their shifts at work. 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).
Drawing of one of his first balance springs, attached to a Balance Wheel , by Christiaan huygens published in his letter in the Journal des Sçavants of 25 February 1675. The application of the Spring Balance Spring (Sprial Hairspring for watches ushered in a new era of accuracy for portable timekeepers, similar to that which the Pendulum had introduced for Clocks.
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 Christian Huygens This innovation 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. The first thing to be improved was the Escapement. The verge escapement was replaced in quality watches by the Cylinder Escapment, invented by Thomas Tompion in 1695 and further developed by George Graham in the 1720s. 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.
A major cause of error in balance wheel timepieces, caused by changes in Elasticily of the Balance Spring from temperature changes, was solved by the bimetallic Temperature Compensated Balance Wheel nvented in 1765 by Pierre Le Roy and improved by Thomas Earnshaw.The lever Escapement was the single most important technological breakthrough, and was invented by Thomas Mudge in 1759 and improved by Josiah Emery in 1785, although it only gradually came into use from about 1800 onwards, chiefly in Britain.
A watch drawn in Acts Eruditorum,1737
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 Sates that this system took off. Aron Lufkin Dennison started a factory in 1851 in Massachusets that used Interchangeable Parts,and by 1861 it was running a successful enterprise incorporated as the Waltham watch Company.