You jiangu’s Candle clock

You Jiangu’s candle clock consisted of six candles made from 72pennyweights of wax, each being 12 inches high, of uniform thickness, and divided into 12 sections each of one inch. Each candle burned away completely in four hours, making each marking 20 minutes. The candles were placed for protection inside cases made of a wooden frame with transparent horn panels in the sides. Similar methods of measuring time were used in medieval churches and earlier, famously byKing Alfred the Great of England, first by counting the number of candles of a specific size burnt, and later by use of a graduated candle.

Clock