O U T R E A C H.

A candle clock is a thin candle with consistently spaced markings (usually with numbers), that when  burned, indicate the passage of periods of time. While no longer used  today, candle clocks provided an effective way to tell time indoors, at  night, or on a cloudy day. A candle clock could be easily transformed  into a timer by sticking a heavy nail into the candle at the mark  indicating the desired interval. When the wax surrounding the nail  melts, the nal clatters onto a plate below. It is unknown where and when candle clocks were first used. The earliest reference to their use occurs in a Chinese poem by You Jiangu (520 AD). Here, the graduated candle supplied a means of determining time at night. Similar candles were used in Japan until the early 10th century.