About: http://webisa.webdatacommons.org/353417330

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	Usually a liquid such as mercury, water, or some low vapour pressure liquid of the desired density is placed in a U-tube.
http://www.w3.org/ns/prov#wasQuotedFrom	iupac.org