How did R.A.B fill the basin with the same potion that Voldemort had originally used? Was he even smarter than Dumbledore, and realized even before entering the cave that it had a potion and researched or made that potion? Not very likely, is it? Was it such that the basin refilled itself? But that won't be any use once the horcrux was taken?

  • 1
    and after Dumbledore drank it too...
    – LilyM
    Apr 22, 2016 at 12:29

1 Answer 1


We've seen magical liquids which reconstitute themselves before. Way back in Harry Potter and the Sorcerer's Stone we see potion bottles which refill themselves (Quirrelmort must have drank the 'move forward through the black flames' potion just like Harry did).

It is almost certainly a difficult or time-consuming process, or one which is limited to certain potions. If it weren't, or if it were a spell which could be cast upon a container to recreate a potion, we would see evidence of this elsewhere. Barty Jr wouldn't have had to steal ingredients from Snape's lab if he could have enchanted the polyjuice or his flask to refill automagically. The luck potion wouldn't be so rare if it could be put into an eternal bottle. And don't get me started on the uses the Death Eaters would have for a constantly refilling poison potion.

Therefore, it was not R.A.B., but Voldemort who caused the basin to be refilled. Either the basin refills itself with the potion or the potion creates more of itself (to a point).

The reason Voldemort would desire this is simple: he had taken great pains to ensure that only one person could reach that island. The water was full of zombies, and the boat would carry only one person. One person, drinking the potion, would be incapacitated. Voldemort, who never considered that a second person (with a significantly less potent magical presence) could ride along in the boat. There was only ever to be a single person on the island, which was designed to be a prison or deathtrap for anyone who made it there.

Voldemort's plan was for him to easily retrieve whomever may have drank the potion and been incapacitated and interrogate them (no one was to know of the existence of the Horcruxes, after all). It would have been much easier for him to not have to manually refill the potion each time, or to have the potion refill itself so that a second person who managed to reach the island couldn't steal the Horcrux in the mean time.

  • I agree with the first part, quite right as I myself predicted that it could refill itself. but the point is it would be useless to refill itself if the person drank it all and suppose got the horcrux? maybe riddle was after all not as brilliant-minded...:D
    – roonham
    Nov 4, 2013 at 16:12
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    "Way back in Harry Potter and the Sorcerer's Stone we see potion bottles which refill themselves (Quirrelmort must have drank the 'move forward through the black flames' potion just like Harry did)." My recollection is that the bottle had already been drunk from by Quirrell and as a result practically empty, which is why Harry has to go alone rather than taking Hermione with him, rather than it just being completely full yet so small that there's only enough for one of them. Nov 4, 2013 at 16:48
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    @AnthonyGrist: Nope, it was full, but the bottle was the smallest and barely held enough for a mouthful. There's no mention of it having already been drank from. I just reread that part of the book last week.
    – Jeff
    Nov 4, 2013 at 18:09
  • @roonham: It wouldn't be useless to refill itself. The point of the potion was to incapacitate whomever drank it, so they couldn't steal the horcrux. Riddle was just overconfident in his other defenses ability to prevent more than one person from reaching the island.
    – Jeff
    Nov 4, 2013 at 18:11
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    +1. As a programmer, I'd give you another +1 (if I could) for using "automagically" in a context actually involving magic :-) Nov 15, 2013 at 18:31

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