Carcel

noun

1. A French unit of illuminating power, equal to the light emitted by a standard lamp with a flame 40 millimeters high and burning 42 grams of colza-oil an hour.
2. A light standard much used in France, being the light from a Carcel lamp of stated size and construction consuming 42 grams of colza oil per hour with a flame 40 millimeters in height. Its illuminating power is variously stated at from 8.9 to 9.6 British standard candles.
3. A former unit to measure the intensity of light, approximately 9.74 candelas