Dating your watch
The application of the spiral balance spring (spiral 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 Christiaan Huygens.
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.
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.
A wristwatch is designed to be worn around the wrist, attached by a watch strap or other type of bracelet.
A pocket watch is designed for a person to carry in a pocket.
Some watches use radio clock technology to regularly correct the time.
Developments in the 2010s include smartwatches, which are elaborate computer-like electronic devices designed to be worn on a wrist.
Early models were essentially standard pocket-watches fitted to a leather strap but, by the early 20th century, manufacturers began producing purpose-built wristwatches.Time-related features such as timers, chronographs and alarm functions are common.Some modern designs incorporate calculators, GPS and Bluetooth technology or have heart-rate monitoring capabilities.Aaron Lufkin Dennison started a factory in 1851 in Massachusetts that used interchangeable parts, and by 1861 it was running a successful enterprise incorporated as the Waltham Watch Company.The concept of the wristwatch goes back to the production of the very earliest watches in the 16th century.
A watch is a timepiece intended to be carried or worn by a person.