Assertion: alder's bark | /r/MadeOf | tannic acid
Facets:
Source sentences:
text: The bark and twigs contain 16 to 20% tannic acid but their usefulness in tanning is limited by the strong accompanying color they produce.
text: The bark and twigs contain 16 to 20% tannic acid but their usefulness in tanning is limited by the strong accompanying colour they produce.