Harry would have noted if an alarm went off or the cloak started glowing or buzzing or whatnot. That would be the way an ancient artifact would be revealed, right?
One of them in particular made Hermione’s heart sink; she recognized it as the Charm which had been listed alongside the description of the True Cloak of Invisibility, which would not reveal the Cloak, but would tell you whether it or certain other artifacts were nearby.
I assumed the caster of the spell silently becomes aware of the fact “there is an artifact nearby”. I guess it might be possible it sounds an alarm instead, but that would require that mokeskin pouches can beat artifact-detecting spells, which seems unlikely.
If, say, Rita Skeeter knew or guessed that we would come here, it is possible that she could be in this room wearing the true Cloak of Invisibility. Or she could be an Animagus with a tiny form, perhaps. There are tests to rule out such rare possibilities, but to perform all of them would be arduous.
Professor Quirrell grinned, then took out his wand and flicked it in the direction of the door. “Of course,” he said, “people who lead interesting lives take precautions more thorough than the dalliers. I have just sealed us in. Nothing will now pass in or out of this room—through the crack under the door, for example. And...”
Professor Quirrell then spoke no fewer than four different Charms, none of which Harry recognized.
“Even that does not really suffice,” said Professor Quirrell. “If we were doing anything of truly great import, it would be necessary to perform another twenty-three checks besides those. If, say, Rita Skeeter [...]
Which raises the question of what the last two Charms in the set of thirty are; but the clear implication is that the spell that would detect the presence of the Cloak of Invisibility is part of the “twenty-three checks” which he performs on other occasions in Harry’s presence.
That was actually called the Caterwauling Charm, though. There’s another detection spell in DH: Hominem Revelio. The only known effects of this spell are (i) the ‘swooping sensation’ experienced by a detected person and (ii) the lack of any alarm when nobody is detected. It’s likely, however, that there is no alarm even when persons are detected; when it’s used against Harry, Ron, and Hermoine by Death Eaters there is no alarm mentioned in the text.
Harry would have noted if an alarm went off or the cloak started glowing or buzzing or whatnot. That would be the way an ancient artifact would be revealed, right?
I assumed the caster of the spell silently becomes aware of the fact “there is an artifact nearby”. I guess it might be possible it sounds an alarm instead, but that would require that mokeskin pouches can beat artifact-detecting spells, which seems unlikely.
My bet, honestly, is that the Cloak of Invisibility laughs at artifact-detecting spells.
Which raises the question of what the last two Charms in the set of thirty are; but the clear implication is that the spell that would detect the presence of the Cloak of Invisibility is part of the “twenty-three checks” which he performs on other occasions in Harry’s presence.
I’m fairly certain that’s how detection spells work though. In Deathly Hallows there were blaring alarms when the gang apparated into Hogsmead.
That was actually called the Caterwauling Charm, though. There’s another detection spell in DH: Hominem Revelio. The only known effects of this spell are (i) the ‘swooping sensation’ experienced by a detected person and (ii) the lack of any alarm when nobody is detected. It’s likely, however, that there is no alarm even when persons are detected; when it’s used against Harry, Ron, and Hermoine by Death Eaters there is no alarm mentioned in the text.