But chemical mordants such as alum are popular today. 但化学腐蚀剂如明矾今天已经十分普遍。
Mix8 grams of alum with7 grams of cream of tartar in a small amount of hot water. 将八克明矾和七克的酒石混合在少量的热水中。
alum
[ noun ]
a white crystalline double sulfate of aluminum: the ammonium double sulfate of aluminum
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a white crystalline double sulfate of aluminum: the potassium double sulfate of aluminum
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a person who has received a degree from a school (high school or college or university)
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a double sulphate of aluminum and potassium that is used as an astringent (among other things)
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Alum \Al"um\, n. [OE. alum, alom, OF. alum, F. alun, fr. L. alumen alum.] (Chem.) A double sulphate formed of aluminium and some other element (esp. an alkali metal) or of aluminium. It has twenty-four molecules of water of crystallization.
Note: Common alum is the double sulphate of aluminium and potassium. It is white, transparent, very astringent, and crystallizes easily in octahedrons. The term is extended so as to include other double sulphates similar to alum in formula.
Alum \Al"um\, v. t. To steep in, or otherwise impregnate with, a solution of alum; to treat with alum. --Ure. ※ ||