"Library books are not to be taken outside the school ... Give it to me. Five points from Gryffindor."
-- Severus Snape (PS11)
Harry, Hermione and Ron are standing in the Hogwarts Courtyard on a cold November day, staying warm with a jar full of Bluebell Flames. Snape approaches and they notice he is limping. He tells Harry that library books are not allowed out-of-doors, and takes away Quidditch Through the Ages.
Timeline Notes
This chapter begins the first week of November. Harry's run-ins with Snape happen on Friday the 8th, and the Quidditch match is on Saturday the 9th. (There is a remote possibility that the events are taking place the next week Friday and Saturday, November 15 and 16, but it is not very likely.)
Commentary
Notes
Harry thought it was unfair that Snape took away his library book, and felt that the Potions Master "just made that rule up" (PS11). But why did Snape bother to limp on a bad leg out into a "freezing" courtyard just to give Harry a bad time about a book? Some readers feel that Snape was favoring the Slytherins once again, perhaps taking away the book to give to one of his own First Year players. Other readers believe Snape was being mean and just wanted Harry to fail at Quidditch the next day, so took away the best guidebook to the sport. And yet the next morning at breakfast, Snape goes out of his way to wish Harry luck, and tells him that after tangling with a Mountain Troll, Quidditch will be a piece of cake. So it's possible that seeing Harry reading a book in the cold Courtyard, Snape surmised that Harry was nervous, whether through Legilimency or intuition, and took away the book to keep the boy from obsessing about the Quidditch match.