About: http://webisa.webdatacommons.org/4542213

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	My understanding is that the sphere is an attempt to take all the variation in the brightness of a light source and average it out so that a reading of the light intensity will correspond to the total lumen output.
http://www.w3.org/ns/prov#wasQuotedFrom	candlepowerforums.com