Article · Wikipedia archive · Last revised Jun 16, 2026

Carcel

The carcel is a former French unit for measuring the intensity of light. The unit was defined in 1860 as the intensity of a Carcel lamp with standard burner and chimney dimensions, which burnt colza oil at a rate of 42 grams of colza oil per hour with a flame 40 millimeters in height.

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Jun 16, 2026
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The carcel is a former French unit for measuring the intensity of light. The unit was defined in 1860 as the intensity of a Carcel lamp with standard burner and chimney dimensions, which burnt colza oil1 (obtained from the seed of the plant Brassica campestris) at a rate of 42 grams of colza oil per hour with a flame 40 millimeters in height.23

In modern terminology, one carcel equals about 9.74 candelas.1

References

References

  1. Rowlett, Russ. "Carcel entry". How Many? A Dictionary of Units of Measurement. University of North Carolina at Chapel Hill. Archived from the original on 2013-08-16. Retrieved 2009-05-13.
  2. "Carcel definition". Webster's Revised Unabridged Dictionary, published 1913 by C. & G. Merriam Co. The Free Dictionary. 2009. Retrieved 2009-05-13.
  3. Johnston, S.F. (Feb 23, 2004). "History of light and color" (PDF). eKnigu Science library. Archived from the original on June 16, 2010. Retrieved 2009-05-13.