Lux 2 : A unit of illumination equal to the direct illumination on a surface that is everywhere one meter from a uniform point source of one candle; a unit of illumination that is equal to one lumen per square meter. Also see footcandle
United States Department of Agriculture USDA, Glossary of Terms, Washington, DC, USA 2014. http://www.usda.gov/energy/matrix/FindTerms, (Oil - Amer) {780}