Oil-lamp clock
From Wikipedia, the free encyclopedia
Oil-lamp clocks, also known as lamp clocks[1] or silent clocks are a type of clock consisting of a graduated glass reservoir to hold oil - typically whale oil,[2] which burned cleanly and evenly - supplying the fuel for a built-in lamp. As the level in the reservoir dropped, it provided a rough measure of the passage of time and the light source allowed the clock to be read at night time.[3] Oil lamps were used for time keeping as early as the 15th Century.[4]
