Hourglass

The main drawback of the solar hours was the fact that it was impossible to use at night and on cloudy days. This problem was eventually solved around 1500 to n. e, when the Egyptians invented the clepsydra, or water clock. The simplest form of such a clock consisted of a vessel with a small hole at the bottom. Filled in a vessel of water slowly flowed through a hole and the water level relative to the marked scale indicates the time that has passed.
The Sunny hours came the sand in which the sand is poured through the narrowing part of the glass vessel, showing after a certain period of time, often a half hour or an hour. Today the miniature hourglass is used in the home while cooking eggs.
To time also used a candle. Notches on wax showed how long hours from time of inflammation. Candles were widely used for timekeeping, but was not an exact instrument, because different wicks, wax varieties and thrust affect the burning rate.