"If you’re referring to the ones that Dumbledore’s army used, Draco had told me about it and I copied the idea, with slight changes though. You have to hold the galleon in one hand and think about the person or persons to whom you want to convey a message. After it feels warm in your hand, you’ll think about the message in your head and it appears on the other person’s coin." Hermione replied, taking a quick glance at her watch. Only half an hour till the train would leave; she didn’t have much time left to convince him.