Stone of Galveston

Edmund talking to Percy about Princess Infanta...

Percy: You know, they do say that the Infanta's eyes are more beautiful than the famous Stone of Galveston.
Edmund: Mm! ... What?
Percy: The famous Stone of Galveston, My Lord.
Edmund: And what's that, exactly?
Percy: Well, it's a famous blue stone, and it comes ... from Galveston.
Edmund: I see. And what about it?
Percy: Well, My Lord, the Infanta's eyes are bluer than it, for a start.
Edmund: I see. And have you ever seen this stone?
Percy: (nods) No, not as such, My Lord, but I know a couple of people who have, and they say it's very very blue indeed.
Edmund: And have these people seen the Infanta's eyes?
Percy: No, I shouldn't think so, My Lord.
Edmund: And neither have you, presumably.
Percy: No, My Lord.
Edmund: So, what you're telling me, Percy, is that something you have never seen is slightly less blue than something else you have never seen.
Percy: (finally begins to grasp) Yes, My Lord.