carcel

plural carcels

1. historicalA former unit to measure the intensity of light, approximately 9.74 candelas.

   In all systems of lighting, save electricity, the unit of light is the carcel.

   1896, Various, Scientific American Supplement, No. 1082, September 26, 1896

   2 more examples

   Desroziers in a series of experiments obtained as much as 250 carcel spherical luminous value per horse-power; this characteristic is one likely to be of great value in electric lighting by incandescence of high intensity.

   1885, Various, Scientific American Supplement, No. 488, May 9, 1885

   When experimenting in Paris with a No. 3 lamp in a vertical direction, it showed a consumption of 34.6 liters (1.2 cubic feet) per carcel obtained.

   1888, Various, Scientific American Supplement, No. 664, September 22,1888

1. A surname