The mechanical clock was probably invented in medieval Europe. Clever arrangements of gears and wheels were devised that turned by weights attached to them. As the weights were pulled downward by the force of gravity, the wheels were forced to turn in a slow, regular manner. A pointer, properly attached to the wheels, marked the hours.

 

These clocks became common in churches and monasteries and could be relied upon to tell when to toll the bells for regular prayers or church attendance. (The very word "clock" is from the French cloche, meaning "bell.")

 

Eventually, mechanical clocks were designed to strike the hour and even to chime the quarter-hour. However, they had only an hour hand and were not enclosed. Even the best such clocks would gain or lose up to half an hour a day.