One of my favorite parts of Sorcerer’s Stone that didn’t make it into the movie is the potions room, where Harry and Hermione have to choose between seven potion bottles using only this poem to guide them:
Danger lies before you, while safety lies behind,
Two of us will help you, whichever you would find,
One among us seven will let you move ahead,
Another will transport the drinker back instead,
Two among our number hold only nettle wine,
Three of us are killers, waiting hidden in line.
Choose, unless you wish to stay here forevermore,
To help you in your choice, we give you these clues four:
First, however slyly the poison tries to hide,
You will always find some on nettle wine’s left side;
Second, different are those who stand at either end,
But if you would move onward, neither is your friend;
Third, as you see clearly, all are different size,
Neither dwarf nor giant holds death in their insides;
Fourth, the second left and the second on the right
Are twins once you taste them, though different at first sight.
Back before Pottermore got its makeover, you used to be able to try to figure it on there. That feature is gone now, but that doesn’t mean I can’t solve it on my blog.
Let’s do the most obvious clue first: “Neither dwarf nor giant holds death in their insides”, so the small blue bottle and the large black one can’t be poison.
“Different are those that stand at either end / But if you would move onward, neither is your friend” – we’ll come back to the fact that they’re different later, but for now, let’s put down that neither one will move you forward.
“the second left and second on the right / are twins once you taste them, though different at first sight” – this means neither one can be the potion to take the drinker backwards or forwards, since there is only one of each of those. Since we’ve already established that the largest bottle isn’t poison, that means it has to be wine.
Which means the second from the left is also wine, since they’re the same.
“however slyly the poison tries to hide / you will always find some on nettle wine’s left side” – this means the bottle on the far left and the one on the left of the largest bottle must both be poison.Now we come back to “different are those who stand at either end” – if the one on the far left is poison, that means the one on the far right can’t be, and since we already know which two are wine, that means it must be the one to take the drinker back.
This leaves the potion to take the drinker forward as the only thing the smallest bottle could be …
… which in turn leaves the middle bottle as the third poison.