[Well, perhaps someone might be able to tell him to avoid touching the orb, or tell him something about it-- but unfortunately, Matt can do neither as he can't exactly tell what it is near the fountain. Something is there, sure, there's the faint sound of air moving around it, but he can't tell what that something is... only that it's a cause for puzzlement for Porthos.
Of course, he says none of this -- instead, there's the steady tapping of his cane against the pavement as he walks closer, deliberately walking so that if he continues, he'll run straight into whatever thing there is floating in the air... unless Porthos tells him not to do it, of course. (He's counting on it-- hard to talk to someone when you're not really supposed to know they're even there.)]