About: http://webisa.webdatacommons.org/307482818

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	The 'ball' is an Integrating Sphere, used to measure the various characteristics of light sources, especially 'power output' - luminous intensity, etc.
http://www.w3.org/ns/prov#wasQuotedFrom	shorpy.com