Where did your clock system come from?
The ancient civilizations of Egypt, Sumer, India, and China defined the hour as either one twelfth of the time between sunrise and sunset or one twenty-fourth of a full day. The clocks of the early Egyptians showed 24 hours, but after the 14th century many clocks were made to register only 12 hours, with two 12 hour periods making up one day. Over two thousand years ago the Babylonians found it convenient to use a sexagesimal (base-60) system to divide the time of an hour into smaller units for their astronomical calculations. The first fractional sexagesimal place is now call a minute, one-sixtieth of an hour, and a second is one-sixtieth of a minute. This system was gradually adopted throughout the civilized world. Instead of minutes, however, many people still refer to a part of an hour as 'a quarter of an hour', 'half past the hour', or 'just before the hour', etc.