# Muggles' Guide to Harry Potter/Books/Philosopher's Stone/Chapter 16

Chapter 16 of Harry Potter and the Philosopher's Stone: Through the Trapdoor← Chapter 15 | Chapter 17 →

## Synopsis

End of term exam time comes, with both written and practical tests. Future Harry would not be able to figure out how he was able to take exams while worrying that Voldemort was about to burst through the door and kill him. With the exams' end, Ron and Hermione are relaxed, though Harry is not; his scar is hurting more than ever, indicating danger is approaching.
Harry suddenly realizes that he must check something with Hagrid—he needs more detail about where Hagrid got the Dragon's egg—dragon eggs are not exactly something that one idly carries around, after all. Hagrid, when confronted, does not know what the man he won the egg from looked like—the man kept his hooded cloak on. Hagrid also told this stranger that Fluffy, the three-headed dog, would calm down if he was played a bit of music.
Harry, Ron, and Hermione, realizing that someone knows how to get past the three-headed dog, run to tell Professor Dumbledore. Professor McGonagall informs them that he has been called away to London. They try to trail Professor Snape, but fail. Harry resolves to go down the trap door as soon as the Gryffindor common room clears; Hermione and Ron immediately elect to go with him.
As they prepare to leave, Neville notices them and attempts to block their departure, refusing to allow Gryffindor to lose any more House points. Hermione regretfully puts him in a full body bind. Under the Invisibility Cloak, they leave the common room and make their way to the third-floor corridor where they find the door is already open. Using the flute that Hagrid gave him, Harry plays Fluffy to sleep, then they jump down the trap door, into a crop of Devil's Snare. Hermione, recognizing what it is, but needing to be prompted by Ron, neutralizes the plant. From there, they enter a chamber full of what appear to be birds flying, but are actually enchanted keys. They can only escape by catching the right key using broomsticks. Naturally, Harry manages this with Ron's and Hermione's assistance. The next trap is a gigantic and violent wizard chess set. Ron brilliantly navigates them across the board by winning the game, but he is injured. After checking his condition, Harry and Hermione then pass on through a chamber in which there is a Troll that is, luckily, already knocked out. They move on to the next challenge, a logic puzzle, which Hermione solves. However, only one can proceed further, and Harry sends Hermione back to help Ron and summon help. Harry enters the last chamber. Someone is there, but it is not Snape.

## Analysis

The Trio is starting to work together, and we see them deriving strength from their combined talents. Each plays a vital role in reaching the Philosopher's Stone, whereas, one alone, and even two, would have likely failed. Hermione's magical ability and intellect allowed the three to escape the Devil's Snare and she solved the logic puzzle; Harry's flying talent was required to catch the key; and Ron's strategic skills were needed on the Wizard's Chess board. Notably, however, they were not simply taking turns. Ron had to prompt Hermione into conjuring a light to evade the Devil's Snare, and Harry needed Ron's and Hermione's help on the brooms to corner the key.
It was mentioned earlier that certain staff and teachers provided the protection for the Stone. In order, that would be: Hagrid (Fluffy), Professor Sprout (Devil's Snare), Professor Flitwick (charmed keys), Professor McGonagall (wizard chess set), Professor Quirrell (as we will shortly find out, the troll), and Professor Snape (potions for the logic puzzle). While we have been told that Professor Dumbledore has also contributed, his magical protection is unseen yet.
Neville's opposing the Trio is the first occasion where we have seen him evince any bravery whatsoever. Until now, he has seemed ineffectual, magically weak, and at the mercy of the passing scene. It certainly seemed questionable that the Sorting Hat placed him in Gryffindor, a house known for bravery. But Gryffindor also represents nobility, as well as courage, and the Hat apparently detected both those traits within him that, here, we see for the first time when he opposes the others. His opposition is futile, to be sure, but he believes he is protecting his House from losing more points due to what he feels is the Trio's inappropriate actions. This chapter marks a milestone in Neville's maturation, and his bravery and noble nature are gradually becoming more overt. Whether or not his magical ability can also progress remains to be seen, however.
One small point deserves notice here: It is mentioned in passing that Harry has trouble sleeping because, "he kept being woken by his old nightmare." Only twice have dreams been mentioned previously in this book. The first, Harry's vision of a flying motorbike from the early chapters, is by no means a nightmare; Harry seems to recall it as being exciting. The other dream mentioned dates back to Harry's first night at Hogwarts, and it is mentioned there that he had forgotten the dream by the next morning. So it would seem we are unacquainted with Harry's old nightmare, and there is no immediate explanation for this discrepancy.

### Logic puzzle

The logic puzzle Hermione solves is interesting, in that we see the question, and the solution, but not the initial setup. The solution, as determined by Hermione, is that the smallest bottle will move you forward, and the one at the right end of the line will take you back. Clearly, from the arrangement of the bottles and the associated clues, it is possible for Hermione to determine which potion is which. Is it possible, from the clues and Hermione's solution, to work backwards and determine what the arrangement must have been? In fact, it does not, as the third clue is based on the bottles' sizes, which we are not told; however, it does refine it to one of two possible setups, both of which are uniquely solvable from the clues provided.
There are seven differently-shaped bottles on the table in front of them, and the puzzle text is:
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 this 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 onwards, 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.
Is this enough to determine the initial arrangement of bottles? Let us say that B is the potion that allows you to go back, F is the potion that allows you to move forward, W is wine, and P is poison.
| From the Poem, we know that there are 3 P's, 2 W's, 1 B, and 1 F. Let us start blank. | _ _ _ _ _ _ _ |
| We know from Hermione's solution that B is the farthest to the right. | _ _ _ _ _ _ B |
| From the 2nd clue, we learn that neither end can be F, so the furthest to the left must be B, W, or P. It cannot be W, since there is always Poison to Wine's left, from clue 1, and there is no spot to the left of the leftmost. As we know where B is already, we also know that it cannot be B. Therefore, it must be P. | P _ _ _ _ _ B |
| Clue number 1 tells us that each of the two bottles of wine has poison to its left. If wine is not the second bottle, then we have the following choices for the remaining two P and the two W: P P W P W _ BP P W _ P W BP _ P W P W B Clue 4 rules out all of these choices, because in none of them does the sixth bottle match the second. Additionally, it rules out the possibility that the second bottle is the Forwards potion, as there is only one bottle of F and so if it is in position 2, it will not match what is in position 6. So the second bottle must be wine. | P W _ _ _ _ B |
| Now, we know that "second left and second on the right" are the same from clue number 4, so the second from the right must also be wine. | P W _ _ _ W B |
| And now, apply clue number 1 again — poison to the left of the wine. | P W _ _ P W B |
| At this point it becomes indeterminate as we can't see the sizes of the bottles to allow clue 3 to help us. The two solutions are equally likely, but whichever of the two is the "dwarf", the smallest of the lot, will be the Forward bottle, that being the only one not yet determined. | P W F P P W B P W P F P W B |
Given this arrangement, we note that clue 3, "neither dwarf nor giant holds death," means that the giant must be one of the two wine bottles, as from Hermione's solution we know that the Back potion is a smaller bottle, and the Forward potion is the smallest.
So, starting from the arrangement above, Hermione sees that the "giant" in clue 3 is either 2 or 6, meaning the largest bottle must be wine, back, or forward potion. Clue 4 tells her that 2 and 6 are both not poison, therefore they must both be wine, as there is only one of forward potion or back potion; and clue 1 tells her that 1 and 5 must both be poison.
As both wine bottles have been identified, and clue 2 says that 7 must be different from 1 but cannot be Forward, and we know that 1 is Poison, the only option available is that 7 is Back.
With three of the four non-poison bottles identified, and none of them the "dwarf" mentioned in clue 3, it is easy to determine that the smallest bottle must be Forward, and the one remaining unidentified bottle, neither dwarf nor giant, must be poison.
The analysis above assumes it is somehow possible to tell from which side the line of potion bottles is to be viewed, since the definition of "left" and "right" depend on it. From the written description of the room "... just a table with seven differently shaped bottles standing on it in a line," it is entirely possible the table was in the middle of the room and could be viewed from either side. However, Hermione "walked up and down the line of bottles" rather than around the table while contemplating the puzzle, which would suggest the bottles are only accessible from one side, as they would be if the table were pushed up against a wall. It is possible that Hermione simply assumed that the bottles were to be referred to only from the side of the room where she and Harry entered, and was staying always on that side of the table to ease her own thinking. It would, of course, be possible to affix the poem to the table so that the order of bottles is fixed relative to the poem; however, we are told that the riddle is on a scroll that Hermione can carry around. We have to assume some form of standard reference as to where the leftmost and rightmost bottles are, as the puzzle must be solvable. However, the fact remains that Hermione was lucky that the wizard who had already passed through had not made some trivial rearrangement of the bottles that would have invalidated the entire puzzle, and Harry was lucky that the same wizard had left any of the "go forward" potion for him.

## Questions

Study questions are meant to be left for each student to answer; please don't answer them here.

### Review

* Discuss how Harry, Ron, and Hermione, independently and as a group, overcame the magical barriers protecting the Philosopher's Stone.
* Why does Neville try to stop the Trio from leaving the common room? What does Hermione do?
* Why did Harry want to know where Hagrid got the Dragon's egg?

### Further Study

* If someone had previously passed through the room, why then were all the potions in the logic puzzle still present? Would that person not have had to drink the "onwards" potion at least? And if it was some form of magically refilling bottle, why would only Harry be able to proceed?
* Why was the Troll already knocked out, and who would be able to accomplish such a feat?

## Greater Picture

This chapter is almost pure action; there is very little here that is carried forward to further books. However, the following points should be mentioned.
Until now, Neville's courage has been deeply buried as he has quietly endured a family tragedy that few know about. Neville's increasing strength, bravery, and magical ability will, by the seventh book, result in him becoming a leader in an underground resistance to a Dark organization.
Hermione here shows some concern for Ron; it is impossible to judge, at this early stage, if this is the starting point for their eventual relationship that develops in books six and seven, but one could speculate that a seed has been sown.
One additional point should be raised concerning "Harry's old nightmare," which is mentioned though never explained. Harry will be subject to recurring nightmares in later books, notably visions of the duel in the cemetery after Cedric's death, and later under the malign influence of Voldemort. However, we have not yet been told of any recurring nightmares, so the mention of such in this chapter may be an error, or may simply be premature. We have heard of a dream concerning a green flash and pain in his forehead; we will later learn that this is a direct reference to the night Harry's parents died and Voldemort tried to kill Harry. But we have not heard that this was either a nightmare or recurring.

### Connections

* Ron, upset with Hermione's inertia when faced by the Devil's Snare, yells at Hermione, "Are you a witch, or what?" In Harry Potter and the Deathly Hallows, Hermione, upset with Ron's inertia when faced by the Whomping Willow, yells, "Are you a wizard, or what?" While this was certainly a conscious choice by the author, one must wonder whether it was meant to be a conscious choice by Hermione. It is also perhaps noteworthy that in response to this, Ron uses Wingardium Leviosa, the first charm he ever learned.