Noah Webster
Zaffer
ZAFFER, noun The residuum of cobalt, after the sulphur, arsenic and other volatile matters have been expelled by calcination; so that it is a gray or dark gray oxyd of cobalt, mixed with a portion of silex.
ZAFFER, noun The residuum of cobalt, after the sulphur, arsenic and other volatile matters have been expelled by calcination; so that it is a gray or dark gray oxyd of cobalt, mixed with a portion of silex.