"Well, there you have it!" he said, tottering back onto the platform. "That was a Disarming Charm - as you see, I've lost my wand - ah, thank you, Miss Brown - yes, an excellent idea to show them that, Professor Snape, but if you don't mind my saying so, it was very obvious what you were about to do. If I had wanted to stop you it would have been only too easy - however, I felt it would be instructive to let them see..."