Assertion: calendar's length | /r/HasProperty | determined near the end of the 19th century
Facets:
Source sentences:
text: The length of the second, which corresponds to the length of time required for 9,192,631,770 cycles of the Cesium atom at zero magnetic field, was determined near the end of the 19th century; this second is thus equivalent to the second defined by the fraction 1/31 556 925.97 47 of the year 1900.