The Problem With Sundials
1280-1290 AD
1280 1280
06.55E50.50N
SCI

EUROPE
	For telling time, sundials are okay as long as you have the sun shining down upon you, but what do you do at night?
	That was the problem faced by the Benedictine monks, who had prayers at specific hours throughout the day and night.  It was this problem that led to the creation of the first mechanical clocks.
	The earliest time-keeping mechanisms were gnomon, which originated in China, Mesopotamia or Egypt.  A gnomon is essentially a pole stuck in the ground.  Unfortunately, it was not accurate from season to season.
	Then someone thought of placing the pole parallel to the earth's axis, thus creating the sundial.  This solved much of the accuracy problem, but it did nothing for telling time at night.
	There were other experiments, such as the water clock, which told time by dripping water at a constant rate.  But water clocks tended to freeze in the winter.
	The first mechanical clocks probably appeared around 1280 to 1290 AD in Europe, and were based on a revolutionary device called the "verge and foliot." This device slowed the turns of a toothed wheel by alternately catching and releasing each tooth, allowing it to advance just one tooth each time the wheel was released. Because the wheel turned at a constant, slow speed, all it needed was a dial to make an excellent clock.
	While some of the clocks got the monks out of bed, they quickly became more widespread, appearing in church towers and town hall towers throughout the continent.
	While life probably became less relaxed when clocks started keeping track of every moment, modern commerce and navigation would be impossible without them. Clocks enabled meetings and schedules to be established with precision and the chronometer (a special clock for navigators) enabled sailing ships to determine their longitude (east-west position) with much greater accurately.