Assertion: sperm whale's spermaceti oil | /r/HasProperty | great value
Facets:
value: in century - see
type: TEMPORAL
Source sentences:
text: I edited the section ("Owing to extensive whaling, sperm whale size has decreased dramatically, mostly because the largest males were killed first and most intensively, for they had more spermaceti (spermaceti oil was of great value in the 18th and 19th century - see below).