Note 1. 2. 6 — ACT I.
Reading edition
-9 christalls, ... characters. As in other fields, Jonson is well versed in magic lore. Lumps of crystal were one of the regular means of raising a demon. Bk. 15, Ch. 16 of Scot’s Discovery of Witchcraft, 1584, is entitled: ‘To make a spirit appear in a christall’, and Ch. 12 shows ‘How to enclose a spirit in a christall stone.’