MISTAKES
In Harry Potter and the Chamber of Secrets on page 323 Ginney says "Im going to be expelled! Ive looked forward to coming here ever since Bill came and now I'll have to leave amd-What will mom and Dad say?". But how could Ginney have wanted to go to Hogwarts ever since Bill came since clearly Bill went to school atleast 9 years before meaning Ginney could have been 2 years old or younger. We know this because we know Bill and Charlie have already graduated Hogwarts. Charlie who is the second oldest had to have graduated atleast 8 years ago because when Harry came to hogwarts he had already graduated from Hogwarts. So since Ginney is 11 now how could she have been smart enough when she was 2 to understand what Hogwarts was and even that she was a witch. She couldn't have possibley understoud all of this when she was so young. I mean she was a baby!
On Page 135 it says McGonagall found Colin. A couple paragraphs later it said Dumbledore found him.
Nearly Headless Nick gets petrified by the basilisk, right? Well, all the other students who are petrified receive Mandrake Juice to revive them, but ghosts can eat or drink, as it states in the first book and in an earlier chapter. So how does Nearly Headless Nick recover?
On Harry's Booklist in Chamber of Secrets it says "Year with a Yeti" and "Wanderings with Werewolves". Lockhart talks about "Year with THE Yeti" and "Weekend with a Werewolf".
When Harry is in the infirmary after getting his arm broken by the rogue bludger he wakes up to find Dobby the House Elf next to him. But eventually Dobby disappears when he hears people coming, leaving Harry holding on to thin air. But in the later books Hermione puts a lot of emphasis on the fact that you can't appartate or disapparate in Hogwarts. [In the fourth book, I think, someone says that house elves have thier own kind of magic. Maybe to dissapear like that is something that only a house elf can do.]
In chapter 10 in the US version of Chamber of Secrets, the picture shows Harry with his left arm boneless. However, in the actual chapter it clearly states that his right arm is broken.
The Fireworks favored by the Wasley twins are referred to in full as "Dr Filibuster's Fabulous, Wet-start, No-heat, Fireworks," when the twins are stocking up on them in Diagon Alley. However they are referred to as "Filibuster's Fabulous, No-Heat, Wet-Start, Fireworks" during the taxi ride to King's Cross.
Tom says Harry is a half/half. That's not true Harry had a witch and a wizard for a mom and dad which makes him a pureblood.
while Ron and Harry are trying to figure out how to get to Hogwarts Ron asks if Harry has any muggle money. Harry says no and that the Dursleys haven't given him pocket money for six years. But if you look back in book 1 during Christmas Harry recieves a fifty-pence piece.
Chapter 3, the Weasleys and Harry are eating breakfast after Ron and the twins rescued Harry from Privet Drive. When Fred says he's tired and is going back to bed, Mrs. Weasley says that he has to de-gnome the garden, and he complains. Then Mrs. Weasley says, "And you two." She says this while staring at Ron and Fred. Shouldn't she be staring at Ron and George?
When Harry, Ron and Hermione explore the scene of Mrs. Norris's attack they find scorch marks on the ground. There are no associations between basiliscks and fire made in any of the books, including Magical Creatures and Where to Find Them. Was there another magical creature there. One associated with fire? Perhaps a pheonix?
In Book 2, when Professor McGonagall takes Harry to see Dumbledore about the students getting petrified, she gets in by using "lemon drop" as the password. Later in Book 4, when Mr. Crouch turns up in the forest, Harry tries to gain entrance by using "Sherbet Lemon" as the password, because it said that this was the password two years ago. [Note: Sherbet Lemon is the equivalent of the Lemon Drop in the US books. There were more "changes" made in Book 1 than in following books.]