carcel

{{Short description|Former French unit for measuring the intensity of light}}

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

(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.{{cite web|url=http://www.thefreedictionary.com/Carcel|title=Carcel definition |year=2009|work=Webster's Revised Unabridged Dictionary, published 1913 by C. & G. Merriam Co.|publisher=The Free Dictionary|accessdate=2009-05-13}}{{cite web|url=http://www.eknigu.org/info/P_Physics/PPop_Popular-level/Johnston%20S.F.%20History%20of%20light%20and%20color%20(IOP,%202001)(292s).pdf|title=History of light and color|last=Johnston|first=S.F.|date=Feb 23, 2004|publisher=eknigu Science library|accessdate=2009-05-13|archive-url=https://web.archive.org/web/20100616190922/http://eknigu.org/info/P_Physics/PPop_Popular-level/Johnston%20S.F.%20History%20of%20light%20and%20color%20(IOP,%202001)(292s).pdf|archive-date=June 16, 2010|url-status=dead}}

In modern terminology one carcel equals about 9.74 candelas.{{cite web|url=http://www.unc.edu/~rowlett/units/dictC.html|title=Carcel entry|last=Rowlett|first=Russ |work=How Many? A Dictionary of Units of Measurement|publisher=University of North Carolina at Chapel Hill|accessdate=2009-05-13}}