Overview

Early in history, humans sought methods to tell time. A concept rather than a physical entity, time eluded accurate measurement for many centuries. One of the first successful timekeeping devices was the water clock, which was perfected in China in the eighth century. It wasn't until nearly seven centuries later that mechanical clocks began to make their appearance. Mechanical clocks not only made timekeeping much more precise, which was important for scientific purposes, but also introduced it to the masses when centrally located clock towers equipped with bells loudly struck the hour.

Background

One solar day spans one rotation of the earth on its axis. This natural unit of time is still the basic unit of timekeeping. For a variety of reasons, however...