Carcel lamp

The clockmaker Guillaume Carcel devised a clockwork lamp that he patented in 1800 as the ‘lycnomena lamp’. His invention reduced the shadow cast by the reservoir, now beneath the lamp and not to one side. The oil is continuously raised to the lamp by a suction pump in the reservoir driven by a clockwork mechanism. This elegant and costly lamp was a familiar sight in bourgeois homes during the Restoration. Its inventor gave his name to a French unit for measuring light intensity produced by a standard lamp burning 42 grams of colza oil per hour. This version of his lamp is an expensive ceremonial model in which the clockwork mechanism was replaced by a fan at the top of the glass chimney.