单词 rock alum 释义 rock alum[rock n.1](See alum n. 1 and roche alum.)1671Phillips s.v. Allum, Called Roch or Rock Allum.1678R. Russell tr. Geber iv. iv. 246 Glassy or Rock Allom hath a two fold way of Preparation.a1756Mrs. Heywood New Present (1771) 263...