Assertion: prototype's mass | /r/HasProperty | indistinguishable
Facets:
value: in 1883
type: TEMPORAL
Source sentences:
text: In 1883, the mass of the IPK was found to be indistinguishable from that of the Kilogramme des Archives made eighty-four years prior, and was formally ratified as the kilogram by the 1st CGPM in 1889.