Joined: 23 Aug 2006
Ehren, the gear is underneath that.
No, technically it's not even a gear. The thing that looks like a gear is really the bottoms of those stands that connect to the spines of the books and bring it forward towards you from out of the slot. In other words, each gear "tooth" really has a book attached to the top of it, only to be seen if it is the book called from the Nexus.
If you look in the slot the books come out, you'll even see the "gear tooth" underneath lead up to a closed book back in the darkness. And when you use the Nexus they all start to move when searching, then it stops once it has the right book.