Assertion: pendulum clock | /r/CapableOf | serve as the time
Facets:
value: during the 1930s
type: TEMPORAL
Source sentences:
text: Some of the most accurate pendulum clocks: Riefler regulator clock , that served as the US time standard from 1909 to 1929, Shortt-Synchronome clock , the most accurate pendulum clock ever manufactured, which served as the time standard during the 1930s.