[Merlin takes the hand with a laugh.] I'm Merlin. Er, previous comrade in arms--I surrendered about an hour ago. Playing in the snow's great, but having my boots soaked through isn't as much.

Here, you should take this and warm yourself up. [He pulls a medium-sized towel out of his satchel and breaks some stitching on it before handing it over. It'll feel hot to the touch, but not uncomfortably so, when Dumbledore takes it.]