Missing spell page

[rugged]

Ok I hate asking for hints, but I am wanting to progress the game (remember the days of being stuck on a puzzle for months!!). I have the missing spell page but can't work out how to use it in the spell. Whenever I look at it, it just tells me what is on the back of the page. I tried adding it too the book but that doesn't work. I tried clicking it on the ball once I had made the rest of the cat spell but that doesn't seem to work either. A little hint would be good...

[Music Head]

You have to have the book open to that section. Then you can use the missing page on the book to add it back.