Pocket watches have been used as a form of telling the time for centuries. They can traced back as far as the 1600's and are still in use today.
Pocket watches are designed to fit in a pocket and to prevent them falling out they are attached to fob chain which in turn is secured to a belt loop of waistcoat. Early pocket watches only had hour hands with the minute hand being introduced in the 17th century.
The spread of the railroad in the late 19th century led to an increase in the popularity of pocket watches. Pocket watches use a wind up mechanism though initially early model required a special key. With the advent of wristwatches from companies such as Breil watches, Seiko and Rolex pocket watches are now less popular but they are still being made.