Hermione Introduces Fake Galleons to Coordinate D.A. Meetings

PAGES: 398-399

To keep the timing of Dumbledore's Army meetings unpredictable and secret, Hermione devises a method using fake Galleons. Each coin carries the time and date of the next meeting, and they heat up when the time changes. The system is protected by a Protean Charm, which impresses the group, especially Terry Boot, as it's N.E.W.T. standard magic.