Carcel

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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 oil [1] (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.[2][3]

In modern terminology one carcel equals about 9.74 candelas.[1]

References[edit]

  1. ^ a b Rowlett, Russ. "Carcel entry". How Many? A Dictionary of Units of Measurement. University of North Carolina at Chapel Hill. 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". eknigu Science library. Retrieved 2009-05-13.