He smiles at the insightful questions and continues on. "Depends on the kind of alchemy. In Amestris we use the energy from the shifting of the earth."
Ed thinks about it for a time, then suddenly snaps his fingers. "Father did it once. Not my father, I- it's complicated. Nevermind. But I'm not sure how he managed it. He stopped it cold." Rubbing his chin, Ed considers this silently.